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1.  The Causes and Circumstances of Drinking Water Incidents Impact Consumer Behaviour: Comparison of a Routine versus a Natural Disaster Incident 
When public health is endangered, the general public can only protect themselves if timely messages are received and understood. Previous research has shown that the cause of threats to public health can affect risk perception and behaviours. This study compares compliance to public health advice and consumer behaviour during two “Boil Water” notices issued in the UK due to a routine incident versus a natural disaster incident. A postal questionnaire was sent to 1000 randomly selected households issued a routine “Boil Water” notice. Findings were then compared to a previous study that explored drinking water behaviour during a “Boil Water” notice issued after serious floods. Consumers affected by the routine incident showed a significant preference for official water company information, whereas consumers affected by the natural disaster preferred local information sources. Confusion over which notice was in place was found for both incidents. Non-compliance was significantly higher for the natural disaster (48.3%) than the routine incident (35.4%). For the routine incident, compliance with advice on drinking as well as preparing/cooking food and brushing teeth was positively associated with receiving advice from the local radio, while the opposite was true for those receiving advice from the water company/leaflet through the post; we suggest this may largely be due to confusion over needing boiled tap water for brushing teeth. No associations were found for demographic factors. We conclude that information dissemination plans should be tailored to the circumstances under which the advice is issued. Water companies should seek to educate the general public about water notices and which actions are safe and unsafe during which notice, as well as construct and disseminate clearer advice on brushing teeth and preparing/cooking food.
PMCID: PMC4245651  PMID: 25411725
public health communication; compliance; routine incident; human error; natural disaster; drinking water
2.  Effect of Household-Based Drinking Water Chlorination on Diarrhoea among Children under Five in Orissa, India: A Double-Blind Randomised Placebo-Controlled Trial 
PLoS Medicine  2013;10(8):e1001497.
Sophie Boisson and colleagues conducted a double-blind, randomized placebo-controlled trial in Orissa, a state in southeast India, to evaluate the effect of household water treatment in preventing diarrheal illnesses in children aged under five years of age.
Please see later in the article for the Editors' Summary
Boiling, disinfecting, and filtering water within the home can improve the microbiological quality of drinking water among the hundreds of millions of people who rely on unsafe water supplies. However, the impact of these interventions on diarrhoea is unclear. Most studies using open trial designs have reported a protective effect on diarrhoea while blinded studies of household water treatment in low-income settings have found no such effect. However, none of those studies were powered to detect an impact among children under five and participants were followed-up over short periods of time. The aim of this study was to measure the effect of in-home water disinfection on diarrhoea among children under five.
Methods and Findings
We conducted a double-blind randomised controlled trial between November 2010 and December 2011. The study included 2,163 households and 2,986 children under five in rural and urban communities of Orissa, India. The intervention consisted of an intensive promotion campaign and free distribution of sodium dichloroisocyanurate (NaDCC) tablets during bi-monthly households visits. An independent evaluation team visited households monthly for one year to collect health data and water samples. The primary outcome was the longitudinal prevalence of diarrhoea (3-day point prevalence) among children aged under five. Weight-for-age was also measured at each visit to assess its potential as a proxy marker for diarrhoea. Adherence was monitored each month through caregiver's reports and the presence of residual free chlorine in the child's drinking water at the time of visit. On 20% of the total household visits, children's drinking water was assayed for thermotolerant coliforms (TTC), an indicator of faecal contamination. The primary analysis was on an intention-to-treat basis. Binomial regression with a log link function and robust standard errors was used to compare prevalence of diarrhoea between arms. We used generalised estimating equations to account for clustering at the household level. The impact of the intervention on weight-for-age z scores (WAZ) was analysed using random effect linear regression.
Over the follow-up period, 84,391 child-days of observations were recorded, representing 88% of total possible child-days of observation. The longitudinal prevalence of diarrhoea among intervention children was 1.69% compared to 1.74% among controls. After adjusting for clustering within household, the prevalence ratio of the intervention to control was 0.95 (95% CI 0.79–1.13). The mean WAZ was similar among children of the intervention and control groups (−1.586 versus −1.589, respectively). Among intervention households, 51% reported their child's drinking water to be treated with the tablets at the time of visit, though only 32% of water samples tested positive for residual chlorine. Faecal contamination of drinking water was lower among intervention households than controls (geometric mean TTC count of 50 [95% CI 44–57] per 100 ml compared to 122 [95% CI 107–139] per 100 ml among controls [p<0.001] [n = 4,546]).
Our study was designed to overcome the shortcomings of previous double-blinded trials of household water treatment in low-income settings. The sample size was larger, the follow-up period longer, both urban and rural populations were included, and adherence and water quality were monitored extensively over time. These results provide no evidence that the intervention was protective against diarrhoea. Low compliance and modest reduction in water contamination may have contributed to the lack of effect. However, our findings are consistent with other blinded studies of similar interventions and raise additional questions about the actual health impact of household water treatment under these conditions.
Trial Registration NCT01202383
Please see later in the article for the Editors' Summary
Editors' Summary
Millennium Development Goal 7 calls for halving the proportion of the global population without sustainable access to safe drinking water between 1990 and 2015. Although this target was met in 2010, according to latest figures, 768 million people world-wide still rely on unimproved drinking water sources. Access to clean drinking water is integral to good health and a key strategy in reducing diarrhoeal illness: Currently, 1.3 million children aged less than five years die of diarrhoeal illnesses every year with a sixth of such deaths occurring in one country—India. Although India has recently made substantial progress in improving water supplies throughout the country, currently almost 90% of the rural population does not have a water connection to their house and drinking water supplies throughout the country are extensively contaminated with human waste. A strategy internationally referred to as Household Water Treatment and Safe Storage (HWTS), which involves people boiling, chlorinating, and filtering water at home, has been recommended by the World Health Organization and UNICEF to improve water quality at the point of delivery.
Why Was This Study Done?
The WHO and UNICEF strategy to promote HWTS is based on previous studies from low-income settings that found that such interventions could reduce diarrhoeal illnesses by between 30%–40%. However, these studies had several limitations including reporting bias, short follow up periods, and small sample sizes; and importantly, in blinded studies (in which both the study participants and researchers are unaware of which participants are receiving the intervention or the control) have found no evidence that HWTS is protective against diarrhoeal illnesses. So the researchers conducted a blinded study (a double-blind, randomized placebo-controlled trial) in Orissa, a state in southeast India, to address those shortcomings and evaluate the effect of household water treatment in preventing diarrhoeal illnesses in children under five years of age.
What Did the Researchers Do and Find?
The researchers conducted their study in 11 informal settlements (where the inhabitants do not benefit from public water or sewers) in the state's capital city and also in 20 rural villages. 2,163 households were randomized to receive the intervention—the promotion and free distribution of sodium dichloroisocyanurate (chlorine) disinfection tablets with instruction on how to use them—or placebo tablets that were similar in appearance and had the same effervescent base as the chlorine tablets. Trained field workers visited households every month for 12 months (between December 2010 and December 2011) to record whether any child had experienced diarrhoea in the previous three days (as reported by the primary care giver). The researchers tested compliance with the intervention by asking participants if they had treated the water and also by testing for chlorine in the water.
Using these methods, the researchers found that over the 12-month follow-up period, the longitudinal prevalence of diarrhoea among children in the intervention group was 1.69% compared to 1.74% in the control group, a non-significant finding (a finding that could have happened by chance). There was also no difference in diarrhoea prevalence among other household members in the two groups and no difference in weight for age z scores (a measurement of growth) between children in the two groups. The researchers also found that although just over half (51%) of households in the intervention group reported treating their water, on testing, only 32% of water samples tested positive for chlorine. Finally, the researchers found that water quality (as measured by thermotolerant coliforms, TTCs) was better in the intervention group than the control group.
What Do These Findings Mean?
These findings suggest that treating water with chlorine tablets has no effect in reducing the prevalence of diarrhoea in both children aged under five years and in other household members in Orissa, India. However, poor compliance was a major issue with only a third of households in the intervention group confirmed as treating their water with chlorine tablets. Furthermore, these findings are limited in that the prevalence of diarrhoea was lower than expected, which may have also reduced the power of detecting a potential effect of the intervention. Nevertheless, this study raises questions about the health impact of household water treatment and highlights the key challenge of poor compliance with public health interventions.
Additional Information
Please access these websites via the online version of this summary at
The website of the World Health Organization has a section dedicated to household water treatment and safe storage, including a network to promote the use of HWTS and a toolkit to measure HWTS
The Water Institute hosts the communications portal for the International Network on Household Water Treatment and Safe Storage
PMCID: PMC3747993  PMID: 23976883
3.  An epidemiological study after a water contamination incident near Worcester, England in April 1994. 
STUDY OBJECTIVES: To investigate whether exposure to tap water contaminated in a major river pollution incident with 2 ethyl 5,5 dimethyl 1,3 dioxane (EDD) and 2 ethyl 4 methyl 1,3 dioxolane (EMD) was associated with an increase of self reported symptoms. To assess the extent of association between noticing the water had an unusual taste or odour and self reported symptoms. DESIGN: Retrospective cohort study. SETTING: A city and two nearby towns in a semi-rural area of England, UK. PARTICIPANTS: A total of 3861 people who replied to a postal questionnaire asking about symptoms and water consumption sent to a sample of 1000 households in each of three areas--one area supplied with contaminated water (study group) and two control areas that were unaffected (control groups). MAIN RESULTS: The household response rates were 65% for the study group and 56% and 57% for the two control groups. Self reporting of 10 individual symptoms was significantly increased in the study group compared with controls. Within the study group, reporting of one or more symptoms was significantly higher in subjects who consumed contaminated water but not among subjects who used it to wash or cook. Subjects who drank contaminated water showed a dose-response relationship for self reporting of one or more symptoms and for seven individual symptoms. Within the study group, however, only 62% (867 of 1398 subjects) noticed that the water had an unusual taste or odour. Among subjects who did not notice that the water had an unusual taste or odour, no association was found between drinking contaminated water and reporting one or more symptoms, or between drinking contaminated water and reporting of individual symptoms, although a dose-response relationship was shown between the amount of water consumed and self reporting of nausea. Among subjects who noticed the water had an unusual taste or odour, both an association and a dose-response relationship were found between consumption of contaminated water and the self reporting of six symptoms--diarrhoea, nausea, headache, stomach pains, skin irritation, and itchy eyes. CONCLUSIONS: Higher rates of symptom reporting were associated with the water contamination incident. Reported symptoms seemed, however, to be associated with the ability to detect an unusual taste or odour in the water. Because concentrations of the contaminants would be expected to be evenly distributed in the tap water in the affected area, irrespective of taste or odour, and because of the known toxicity of the parent compounds of EMD and EDD, it is concluded that the increase in self reported symptoms in the study group respondents was associated with noticing the unpleasant taste or odour of the tap water and not with the chemical contamination. It is concluded that the observed increase in reporting of nausea with increasing water consumption was due to public anxiety caused by the incident but did not pose a serious risk to the public's health. The increase in self reported symptoms in the area affected by the contamination was an important reminder of the wider health implications of "health scares".
PMCID: PMC1060198  PMID: 8762348
4.  Land slide disaster in eastern Uganda: rapid assessment of water, sanitation and hygiene situation in Bulucheke camp, Bududa district 
Environmental Health  2011;10:38.
On 1st March 2010, a major landslide occurred on Mt. Elgon in Eastern Uganda. This was triggered by heavy rains that lasted over three months. The landslide buried three villages in Bududa district, killing over 400 and displacing an estimate of 5,000 people. A comprehensive assessment of water, sanitation and hygiene was urgently needed to inform interventions by the Ministries of Health, and Relief, Disaster Preparedness and Refugees, Uganda.
This was a cross-sectional study where both qualitative and quantitative data were collected two weeks after the disaster. Quantitative interviews involved 397 heads of households and qualitative methods comprised of 27 Key Informant interviews, four focus group discussions and observations. The survey quantified water safety (collection, treatment, storage) and hygiene practices. This was supplemented and triangulated with qualitative data that focused on community perceptions and beliefs regarding water and sanitation needs and practices. Quantitative data was entered in Epi-Info Version 3.2.2 software and then exported to SPSS Version 12 for analysis. Summary statistics and proportions were generated and bi-variable analysis performed for selected variables. Associations were assessed using odds ratios at 95% confidence intervals. Qualitative data was analyzed using content analysis.
Qualitative results showed that there were strong traditional beliefs governing water use and human excreta disposal. The use of river Manafwa water for household consumption was observed to potentially lead to disease outbreaks. Water from this river was reported tastier and the community culturally saw no need to boil drinking water. Latrines were few (23 for 5000 people), shallow, dirty (70% reported flies, 60% fecal littering), not separated by sex and had limited privacy and no light at night. This affected their use. Males were 3 times more likely to wash hands with soap after latrine use than females (OR = 3.584, 95%CI: 1.658-7.748). Of the 90% respondents who indicated that they always washed hands after latrine use, 76% said they used water and soap. Observations showed that water and soap were inconsistently available at the hand washing facilities. This situation influenced people's sanitation and hygiene behaviours. Nearly half (48%) indicated that at least a member of their household had fallen sick at least once since arrival at the camp.
There was inadequate access to safe water in the camp. Pit-latrines were inadequate, poorly maintained and not user-friendly for most people. Responsible authorities should design means of increasing and sustaining access to safe water, increase sanitation facilities and continuously educate the public on the need to observe good hygiene practices.
PMCID: PMC3118126  PMID: 21569594
5.  Analysis of Twitter Users’ Sharing of Official New York Storm Response Messages 
Medicine 2.0  2014;3(1):e1.
Twitter is a social network where users read, send, and share snippets of text (“tweets”). Tweets can be disseminated through multiple means; on desktop computers, laptops, and mobile devices, over ethernet, Wi-Fi or cellular networks. This redundancy positions Twitter as a useful tool for disseminating information to the public during emergencies or disasters. Previous research on dissemination of information using Twitter has mostly investigated the characteristics of tweets that are most effective in raising consumer awareness about a new product or event. In particular, they describe characteristics that increase the chance the messages will be shared ("retweeted") by users. In comparison, little has been published on how information from municipal or state government agencies spreads on Twitter during emergency situations. Retweeting these messages is a way to enhance public awareness of potentially important instructions from public officials in a disaster.
The aim of this study is to (1) describe the tweets of select New York State and New York City agencies by public officials surrounding two notable recent winter storms that required a large-scale emergency response, and (2) identify the characteristics of the tweets of public officials that were most disseminated (retweeted).
For one week surrounding Superstorm Sandy (October 2012) and the winter blizzard Nemo (February 2013), we collected (1) tweets from the official accounts for six New York governmental agencies, and (2) all tweets containing the hashtags #sandy (or #nemo) and #nyc. From these data we calculated how many times a tweet was retweeted, controlling for differences in baseline activity in each account. We observed how many hashtags and links each tweet contained. We also calculated the lexical diversity of each tweet, a measure of the range of vocabulary used.
During the Sandy storm, 3242 shared (retweeted) messages from public officials were collected. The lexical diversity of official tweets was similar (2.25-2.49) and well below the average for non-official tweets mentioning #sandy and #nyc (3.82). Most official tweets were with substantial retweets including a link for further reading. Of the 448 tweets analyzed from six official city and state Twitter accounts from the Nemo blizzard, 271 were related to the storm, and 174 had actionable information for the public. Actionable storm messages were retweeted approximately 24x per message, compared to 31x per message for general storm information.
During two weather emergencies, New York public officials were able to convey storm-related information that was shared widely beyond existing follower bases, potentially improving situational awareness and disaster response. Official Sandy tweets, characterized by a lower lexical diversity score than other city- and Sandy-related tweets, were likely easier to understand, and often linked to further information and resources. Actionable information in the Nemo blizzard, such as specific instructions and cancellation notices, was not shared as often as more general warnings and “fun facts,” suggesting agencies mix important instructions with more general news and trivia, as a way of reaching the broadest audience during a disaster.
PMCID: PMC4084767  PMID: 25075245
social media; disaster response; emergencies; public health; emergency management
6.  Public perceptions of drinking water: a postal survey of residents with private water supplies 
BMC Public Health  2006;6:94.
In Canada, the legal responsibility for the condition of private water supplies, including private wells and cisterns, rests with their owners. However, there are reports that Canadians test these water supplies intermittently and that treatment of such water is uncommon. An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An understanding of the perceptions and needs of Canadians served by private water supplies is essential, as it would enable public health professionals to better target public education and drinking water policy. The purpose of this study was to investigate the public perceptions of private water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public education and outreach strategies within the population.
A cross-sectional postal survey of 246 residences with private water supplies was conducted in May 2004. Questions pertained to the perceptions of water quality and alternative water sources, water testing behaviours and the self-identified need for further information.
Private wells, cisterns or both, were the source of household water for 71%, 16% and 13% of respondents, respectively. Although respondents rated their water quality highly, 80% also had concerns with its safety. The most common concerns pertained to bacterial and chemical contamination of their water supply and its potential negative effect on health. Approximately 56% and 61% of respondents used in-home treatment devices and bottled water within their homes, respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared to regular tap water. Testing of private water supplies was performed infrequently: 8% of respondents tested at a frequency that meets current provincial guidelines. Two-thirds of respondents wanted more information on various topics related to private water supplies. Flyers and newspapers were the two media reported most likely to be used.
Although respondents rated their water quality highly, the majority had concerns regarding the water from their private supply, and the use of bottled water and water treatment devices was extensive. The results of this study suggest important lines of inquiry and provide support and input for public education programs, particularly those related to private water testing, in this population.
PMCID: PMC1458329  PMID: 16608511
7.  Reducing the Impact of the Next Influenza Pandemic Using Household-Based Public Health Interventions 
PLoS Medicine  2006;3(9):e361.
The outbreak of highly pathogenic H5N1 influenza in domestic poultry and wild birds has caused global concern over the possible evolution of a novel human strain [1]. If such a strain emerges, and is not controlled at source [2,3], a pandemic is likely to result. Health policy in most countries will then be focused on reducing morbidity and mortality.
Methods and Findings
We estimate the expected reduction in primary attack rates for different household-based interventions using a mathematical model of influenza transmission within and between households. We show that, for lower transmissibility strains [2,4], the combination of household-based quarantine, isolation of cases outside the household, and targeted prophylactic use of anti-virals will be highly effective and likely feasible across a range of plausible transmission scenarios. For example, for a basic reproductive number (the average number of people infected by a typically infectious individual in an otherwise susceptible population) of 1.8, assuming only 50% compliance, this combination could reduce the infection (symptomatic) attack rate from 74% (49%) to 40% (27%), requiring peak quarantine and isolation levels of 6.2% and 0.8% of the population, respectively, and an overall anti-viral stockpile of 3.9 doses per member of the population. Although contact tracing may be additionally effective, the resources required make it impractical in most scenarios.
National influenza pandemic preparedness plans currently focus on reducing the impact associated with a constant attack rate, rather than on reducing transmission. Our findings suggest that the additional benefits and resource requirements of household-based interventions in reducing average levels of transmission should also be considered, even when expected levels of compliance are only moderate.
Voluntary household-based quarantine and external isolation are likely to be effective in limiting the morbidity and mortality of an influenza pandemic, even if such a pandemic cannot be entirely prevented, and even if compliance with these interventions is moderate.
Editors' Summary
Naturally occurring variation in the influenza virus can lead both to localized annual epidemics and to less frequent global pandemics of catastrophic proportions. The most destructive of the three influenza pandemics of the 20th century, the so-called Spanish flu of 1918–1919, is estimated to have caused 20 million deaths. As evidenced by ongoing tracking efforts and news media coverage of H5N1 avian influenza, contemporary approaches to monitoring and communications can be expected to alert health officials and the general public of the emergence of new, potentially pandemic strains before they spread globally.
Why Was This Study Done?
In order to act most effectively on advance notice of an approaching influenza pandemic, public health workers need to know which available interventions are likely to be most effective. This study was done to estimate the effectiveness of specific preventive measures that communities might implement to reduce the impact of pandemic flu. In particular, the study evaluates methods to reduce person-to-person transmission of influenza, in the likely scenario that complete control cannot be achieved by mass vaccination and anti-viral treatment alone.
What Did the Researchers Do and Find?
The researchers developed a mathematical model—essentially a computer simulation—to simulate the course of pandemic influenza in a hypothetical population at risk for infection at home, through external peer networks such as schools and workplaces, and through general community transmission. Parameters such as the distribution of household sizes, the rate at which individuals develop symptoms from nonpandemic viruses, and the risk of infection within households were derived from demographic and epidemiologic data from Hong Kong, as well as empirical studies of influenza transmission. A model based on these parameters was then used to calculate the effects of interventions including voluntary household quarantine, voluntary individual isolation in a facility outside the home, and contact tracing (that is, asking infectious individuals to identify people whom they may have infected and then warning those people) on the spread of pandemic influenza through the population. The model also took into account the anti-viral treatment of exposed, asymptomatic household members and of individuals in isolation, and assumed that all intervention strategies were put into place before the arrival of individuals infected with the pandemic virus.
  Using this model, the authors predicted that even if only half of the population were to comply with public health interventions, the proportion infected during the first year of an influenza pandemic could be substantially reduced by a combination of household-based quarantine, isolation of actively infected individuals in a location outside the household, and targeted prophylactic treatment of exposed individuals with anti-viral drugs. Based on an influenza-associated mortality rate of 0.5% (as has been estimated for New York City in the 1918–1919 pandemic), the magnitude of the predicted benefit of these interventions is a reduction from 49% to 27% in the proportion of the population who become ill in the first year of the pandemic, which would correspond to 16,000 fewer deaths in a city the size of Hong Kong (6.8 million people). In the model, anti-viral treatment appeared to be about as effective as isolation when each was used in combination with household quarantine, but would require stockpiling 3.9 doses of anti-viral for each member of the population. Contact tracing was predicted to provide a modest additional benefit over quarantine and isolation, but also to increase considerably the proportion of the population in quarantine.
What Do These Findings Mean?
This study predicts that voluntary household-based quarantine and external isolation can be effective in limiting the morbidity and mortality of an influenza pandemic, even if such a pandemic cannot be entirely prevented, and even if compliance with these interventions is far from uniform. These simulations can therefore inform preparedness plans in the absence of data from actual intervention trials, which would be impossible outside (and impractical within) the context of an actual pandemic. Like all mathematical models, however, the one presented in this study relies on a number of assumptions regarding the characteristics and circumstances of the situation that it is intended to represent. For example, the authors found that the efficacy of policies to reduce the rate of infection vary according to the ease with which a given virus spreads from person to person. Because this parameter (known as the basic reproductive ratio, R0) cannot be reliably predicted for a new viral strain based on past epidemics, the authors note that in an actual influenza pandemic rapid determinations of R0 in areas already involved would be necessary to finalize public health responses in threatened areas. Further, the implementation of the interventions that appear beneficial in this model would require devoting attention and resources to practical considerations, such as how to staff isolation centers and provide food and water to those in household quarantine. However accurate the scientific data and predictive models may be, their effectiveness can only be realized through well-coordinated local, as well as international, efforts.
Additional Information.
Please access these Web sites via the online version of this summary at
• World Health Organization influenza pandemic preparedness page
• US Department of Health and Human Services avian and pandemic flu information site
• Pandemic influenza page from the Public Health Agency of Canada
• Emergency planning page on pandemic flu from the England Department of Health
• Wikipedia entry on pandemic influenza with links to individual country resources (note: Wikipedia is a free Internet encyclopedia that anyone can edit)
PMCID: PMC1526768  PMID: 16881729
8.  Solar Drinking Water Disinfection (SODIS) to Reduce Childhood Diarrhoea in Rural Bolivia: A Cluster-Randomized, Controlled Trial 
PLoS Medicine  2009;6(8):e1000125.
Daniel Maeusezahl and colleagues conducted a cluster-randomized controlled trial in rural Bolivia of solar drinking water disinfection, and find only moderate compliance with the intervention and no evidence of reduction in diarrhea among children.
Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification method that has been disseminated globally. Laboratory studies suggest that SODIS is highly efficacious in inactivating waterborne pathogens. Previous field studies provided limited evidence for its effectiveness in reducing diarrhoea.
Methods and Findings
We conducted a cluster-randomized controlled trial in 22 rural communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5 y. A local nongovernmental organisation conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 y. Within the intervention arm 225 households (376 children) were trained to expose water-filled polyethyleneteraphtalate bottles to sunlight. Eleven communities (200 households, 349 children) served as a control. We recorded 166,971 person-days of observation during the trial representing 79.9% and 78.9% of the total possible person-days of child observation in intervention and control arms, respectively. Mean compliance with SODIS was 32.1%. The reported incidence rate of gastrointestinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year at risk in the control arm. The relative rate of diarrhoea adjusted for intracluster correlation was 0.81 (95% confidence interval 0.59–1.12). The median length of diarrhoea was 3 d in both groups.
Despite an extensive SODIS promotion campaign we found only moderate compliance with the intervention and no strong evidence for a substantive reduction in diarrhoea among children. These results suggest that there is a need for better evidence of how the well-established laboratory efficacy of this home-based water treatment method translates into field effectiveness under various cultural settings and intervention intensities. Further global promotion of SODIS for general use should be undertaken with care until such evidence is available.
Trial Registration NCT00731497
Please see later in the article for Editors' Summary
Editors' Summary
Thirsty? Well, turn on the tap and have a drink of refreshing, clean, safe water. Unfortunately, more than one billion people around the world don't have this option. Instead of the endless supply of safe drinking water that people living in affluent, developed countries take for granted, more than a third of people living in developing countries only have contaminated water from rivers, lakes, or wells to drink. Because of limited access to safe drinking water, poor sanitation, and poor personal hygiene, 1.8 million people (mainly children under 5 years old) die every year from diarrheal diseases. This death toll could be greatly reduced by lowering the numbers of disease-causing microbes in household drinking water. One promising simple, low-cost, point-of-use water purification method is solar drinking water disinfection (SODIS). In SODIS, recycled transparent plastic drinks bottles containing contaminated water are exposed to full sunlight for 6 hours. During this exposure, ultraviolet radiation from the sun, together with an increase in temperature, inactivates the disease-causing organisms in the water.
Why Was This Study Done?
SODIS has been promoted as an effective method to purify household water since 1999, and about 2 million people now use the approach ( However, although SODIS works well under laboratory conditions, very few studies have investigated its ability to reduce the number of cases of diarrhea occurring in a population over a specific time period (the incidence of diarrhea) in the real world. Before any more resources are used to promote SODIS—its effective implementation requires intensive and on-going education—it is important to be sure that SODIS really does reduce the burden of diarrhea in communities in the developing world. In this study, therefore, the researchers undertake a cluster-randomized controlled trial (a study in which groups of people are randomly assigned to receive an intervention or to act as controls) in 22 rural communities in Bolivia to evaluate the ability of SODIS to reduce diarrhea in children under 5 years old.
What Did the Researchers Do and Find?
For their trial, the researchers enrolled 22 rural Bolivian communities that included at least 30 children under 5 years old and that relied on drinking water resources that were contaminated with disease-causing organisms. They randomly assigned 11 communities (225 households, 376 children) to receive the intervention—a standardized, interactive SODIS promotion campaign conducted by Project Concern International (a nongovernmental organization)—and 11 communities (200 households, 349 children) to act as controls. Households in the intervention arm were trained to expose water-filled plastic bottles for at least 6 hours to sunlight using demonstrations, role play, and videos. Mothers in both arms of the trial completed a daily child health diary for a year. Almost 80% of the households self-reported using SODIS at the beginning and end of the study. However, community-based field workers estimated that only 32.1% of households on average used SODIS. Data collected in the child health diaries, which were completed on more than three-quarters of days in both arms of the trial, indicated that the children in the intervention arm had 3.6 episodes of diarrhea per year whereas the children in the control arm had 4.3 episodes of diarrhea per year. The difference in episode numbers was not statistically significant, however. That is, the small difference in the incidence of diarrhea between the arms of the trial may have occurred by chance and may not be related to the intervention.
What Do These Findings Mean?
These findings indicate that, despite an intensive campaign to promote SODIS, less than a third of households in the trial routinely treated their water in the recommended manner. Moreover, these findings fail to provide strong evidence of a marked reduction of the incidence of diarrhea among children following implementation of SODIS although some aspects of the study design may have resulted in the efficacy of SODIS being underestimated. Thus, until additional studies of the effectiveness of SODIS in various real world settings have been completed, it may be unwise to extend the global promotion of SODIS for general use any further.
Additional Information
Please access these Web sites via the online version of this summary at
The PLoS Medicine editors wrote an editorial arguing that water should be a human right
The World Health Organization provides information about household water treatment and safe storage and about the importance of water, sanitation, and hygiene for health (in several languages)
The SODIS Reference Center provides detailed information about solar water disinfection (in several languages)
The SODIS Foundation in Bolivia provides practical information for the roll-out of solar water disinfection in Latin America (in Spanish and English)
Project Concern International provides information about its campaign to promote SODIS in Bolivia (in Spanish)
The Water Supply and Sanitation Collaborative Council (WSSCC) is a global multi-stakeholder partnership organization with a goal of advocating to achieve sustainable water supply and sanitation for all people
PMCID: PMC2719054  PMID: 19688036
9.  Telling Consumers, Gardeners, and Farmers about the Possible Risk of Rat Lungworm in the Local Food Supply in Hawa‘i 
The rat lungworm, Angiostrongylus cantonensis, uses various species of rats as its definitive hosts and a wide range of slug and snail species as its intermediate hosts.1,2 When ingested by humans, this nematode is a major cause of eosinophilic meningitis.3 However, the risk of consuming the rat lungworm, is extremely low, especially when compared with other food-borne disease agents such as E. coli and Salmonella, or illegal pesticide residues. That said, ingesting a potentially harmful microscopic worm is an unpleasant thought, especially when consumers have seen the potential impact on television, which in serious cases can lead to coma and death, or to long-term neurological malfunction.
On July 8, 2009, the Discovery Channel (a US television channel) ran a 15 minute story on rat lungworm, calling it “one of the most feared parasites on the planet.”4,5 The program covered the story of American tourists who had accidently eaten the parasite in a salad while on vacation in Jamaica in early 2000. While the victims eventually recovered, the story was seen by a large number of viewers. In late 2008 in Hawa‘i, two unrelated individuals had eaten insufficiently washed local produce and had developed the serious eosinophilic meningitis that results from ingesting harmful quantities of the parasite.6 Finally, a November 2011 story in Australia covered the death of an infant who had apparently consumed the rat lungworm parasites while in the family garden.7 The parents of the child were angry with public officials because they did not do more to notify the public of the potential risk in Sydney neighborhoods.
Alerting the public to the presence of a very rare non-communicable yet potentially serious disease is a double-edge sword, especially if it causes them to worry about potential risk associated with their fresh produce. Statistically speaking, consumers in Hawa‘i are much more likely, for example, to get hit by a car while walking across a street than to be infected by the rat lungworm. At the same time, there is a significant push to eat more fresh green vegetables, start school gardens, and bring the vegetables grown into the classroom and/or cafeteria, and for residents and visitors to buy more locally-grown produce. Reducing the use of pesticides that might kill rats and slugs and snails, seems also to be a priority for many. Large media campaigns to inform all consumers (residents and visitors) about a relatively small risk in the local food supply could have a significant economic impact on local produce growers. Health officials continue to struggle with this delicate situation, though the families of those who have been harmed by rat lungworm generally believe that all consumers should be informed of the potential risk as they have seen at first hand the devastating impact of the parasite on a family member.
While public policy should be left to policy makers and implementers, general advice for consumers and food growers can be shared via a range of media. Regarding consumers, first, all vegetables should be inspected for signs of snail or slug damage and discarded if there is any damage. If the plant is intact, for leafy vegetables, such as lettuce, Swiss chard, and celery, all leaves should be pulled apart and all surfaces inspected. This is important because slugs and snails, especially very small juvenile ones, can be found living deep among the leaves and stalks of the plant. Simply rinsing off the outer leaves of produce and then chopping the entire plant, for example for a fresh salad, might just lead to dicing up a live slug or snail, which may (or may not) be infected with rat lungworm. Once the plant has been disassembled and thoroughly inspected, all surfaces should be rinsed and rubbed with drinkable, running, cool water. This is the most effective way to reduce risk, but it is not an absolute guarantee. If a water sanitizing or produce “cleaning” product is used, it may or may not reduce the risk of a slug, snail, or the nematodes themselves being on the food that has been prepared and is about to be served.
As rat lungworms originate in the lungs of rats and undergo part of their development in snails and slugs before being re-ingested by rats in order to complete their development,3 the best way to control or eliminate the risk of infection is to control it at the source by killing the rats and controlling the snails and slugs in the production and processing areas. Unlike pesticides used against other crop and garden pests, which can be spread over an entire field or plant, pesticides for killing rats and slugs and snails are more targeted and come in bait forms. They are therefore generally less effective, and the baits can be highly susceptible to disintegrating in heavy rain. Thus, a methodical program to keep a farm or garden free of rats and slugs and snails needs to be in place.
PMCID: PMC3689482
Angiostrongyliasis; Education; Eosinophilic meningitis; Farmers; Gardeners; General public; Hawaii; Prevention; Rat lungworm
10.  Teenage drinking, alcohol availability and pricing: a cross-sectional study of risk and protective factors for alcohol-related harms in school children 
BMC Public Health  2009;9:380.
There is a lack of empirical analyses examining how alcohol consumption patterns in children relate to harms. Such intelligence is required to inform parents, children and policy relating to the provision and use of alcohol during childhood. Here, we examine drinking habits and associated harms in 15-16 year olds and explore how this can inform public health advice on child drinking.
An opportunistic survey of 15-16 year olds (n = 9,833) in North West England was undertaken to determine alcohol consumption patterns, drink types consumed, drinking locations, methods of access and harms encountered. Cost per unit of alcohol was estimated based on a second survey of 29 retail outlets. Associations between demographics, drinking behaviours, alcohol pricing and negative outcomes (public drinking, forgetting things after drinking, violence when drunk and alcohol-related regretted sex) were examined.
Proportions of drinkers having experienced violence when drunk (28.8%), alcohol-related regretted sex (12.5%) and forgetting things (45.3%), or reporting drinking in public places (35.8%), increased with drinking frequency, binge frequency and units consumed per week. At similar levels of consumption, experiencing any negative alcohol-related outcome was lower in those whose parents provided alcohol. Drunken violence was disproportionately associated with being male and greater deprivation while regretted sex and forgetting things after drinking were associated with being female. Independent of drinking behaviours, consuming cheaper alcohol was related to experiencing violence when drunk, forgetting things after drinking and drinking in public places.
There is no safe level of alcohol consumption for 15-16 year olds. However, while abstinence removes risk of harms from personal alcohol consumption, its promotion may also push children into accessing drink outside family environments and contribute to higher risks of harm. Strategies to reduce alcohol-related harms in children should ensure bingeing is avoided entirely, address the excessively low cost of many alcohol products, and tackle the ease with which it can be accessed, especially outside of supervised environments.
PMCID: PMC2770487  PMID: 19818118
11.  Perceptional and Socio-Demographic Factors Associated with Household Drinking Water Management Strategies in Rural Puerto Rico 
PLoS ONE  2014;9(2):e88059.
Identifying which factors influence household water management can help policy makers target interventions to improve drinking water quality for communities that may not receive adequate water quality at the tap. We assessed which perceptional and socio-demographic factors are associated with household drinking water management strategies in rural Puerto Rico. Specifically, we examined which factors were associated with household decisions to boil or filter tap water before drinking, or to obtain drinking water from multiple sources. We find that households differ in their management strategies depending on the institution that distributes water (i.e. government PRASA vs community-managed non-PRASA), perceptions of institutional efficacy, and perceptions of water quality. Specifically, households in PRASA communities are more likely to boil and filter their tap water due to perceptions of low water quality. Households in non-PRASA communities are more likely to procure water from multiple sources due to perceptions of institutional inefficacy. Based on informal discussions with community members, we suggest that water quality may be improved if PRASA systems improve the taste and odor of tap water, possibly by allowing for dechlorination prior to distribution, and if non-PRASA systems reduce the turbidity of water at the tap, possibly by increasing the degree of chlorination and filtering prior to distribution. Future studies should examine objective water quality standards to identify whether current management strategies are effective at improving water quality prior to consumption.
PMCID: PMC3938413  PMID: 24586302
12.  Human Health and the Biological Effects of Tritium in Drinking Water: Prudent Policy Through Science – Addressing the ODWAC New Recommendation 
Dose-Response  2011;9(1):6-31.
Tritium is a radioactive form of hydrogen and is a by-product of energy production in Canadian Deuterium Uranium (CANDU) reactors. The release of this radioisotope into the environment is carefully managed at CANDU facilities in order to minimize radiation exposure to the public. However, under some circumstances, small accidental releases to the environment can occur. The radiation doses to humans and non-human biota from these releases are low and orders of magnitude less than doses received from naturally occurring radioisotopes or from manmade activities, such as medical imaging and air travel. There is however a renewed interest in the biological consequences of low dose tritium exposures and a new limit for tritium levels in Ontario drinking water has been proposed. The Ontario Drinking Water Advisory Council (ODWAC) issued a formal report in May 2009 in response to a request by the Minister of the Environment, concluding that the Ontario Drinking Water Quality Standard for tritium should be revised from the current 7,000 Bq/L level to a new, lower 20 Bq/L level. In response to this recommendation, an international scientific symposium was held at McMaster University to address the issues surrounding this change in direction and the validity of a new policy. Scientists, regulators, government officials, and industrial stakeholders were present to discuss the potential health risks associated with low level radiation exposure from tritium. The regulatory, economic, and social implications of the new proposed limit were also considered.
The new recommendation assumed a linear-no-threshold model to calculate carcinogenic risk associated with tritium exposure, and considered tritium as a non-threshold chemical carcinogen. Both of these assumptions are highly controversial given that recent research suggests that low dose exposures have thresholds below which there are no observable detrimental effects. Furthermore, mutagenic and carcinogenic risk calculated from tritium exposure at 20 Bq/L would be orders of magnitude less than that from exposure to natural background sources of radiation. The new proposed standard would set the radiation dose limit for drinking water to 0.0003 mSv/year, which is equivalent to approximately three times the dose from naturally occurring tritium in drinking water. This new standard is incongruent with national and international standards for safe levels of radiation exposure, currently set at 1 mSv/year for the general public. Scientific research from leading authorities on the carcinogenic health effects of tritium exposure supports the notion that the current standard of 7,000 Bq/L (annual dose of 0.1 mSv) is a safe standard for human health.
Policy-making for the purpose of regulating tritium levels in drinking water is a dynamic multi-stage process that is influenced by more than science alone. Ethics, economics, and public perception also play important roles in policy development; however, these factors sometimes undermine the scientific evidence that should form the basis of informed decision making. Consequently, implementing a new standard without a scientific basis may lead the public to perceive that risks from tritium have been historically underestimated. It was concluded that the new recommendation is not supported by any new scientific insight regarding negative consequences of low dose effects, and may be contrary to new data on the potential benefits of low dose effects. Given the lack of cost versus benefit analysis, this type of dramatic policy change could have detrimental effects to society from an ethical, economical, and public perception perspective.
PMCID: PMC3057633  PMID: 21431084
Tritium; Health Risk; Carcinogen; Low Dose Radiation; Standard
13.  Public perception of drinking water from private water supplies: focus group analyses 
BMC Public Health  2005;5:129.
Over four million Canadians receive their drinking water from private water supplies, and numerous studies report that these supplies often exceed the minimal acceptable standards for contamination. Canadians in rural areas test their water intermittently, if at all, and treatment of water from private supplies is not common. Understanding the perceptions of drinking water among residents served by private systems will enable public health professionals to better target education and outreach activities, and to address the needs and concerns of residents in their jurisdictions. The purpose of this study was to explore the drinking water perceptions and self-described behaviours and needs of participants served by private water systems in the City of Hamilton, Ontario (Canada).
In September 2003, three focus group discussions were conducted; two with men and women aged 36–65 years, and one with men and women 20–35 years of age.
Overall, participants had positive perceptions of their private water supplies, particularly in the older age group. Concerns included bacterial and chemical contamination from agricultural sources. Testing of water from private supplies was minimal and was done less frequently than recommended by the provincial government. Barriers to water testing included the inconvenience of the testing process, acceptable test results in the past, resident complacency and lack of knowledge. The younger participants greatly emphasized their need for more information on private water supplies. Participants from all groups wanted more information on water testing, and various media for information dissemination were discussed.
While most participants were confident in the safety of their private water supply, the factual basis for these opinions is uncertain. Improved dissemination of information pertaining to private water supplies in this population is needed. Observed differences in the concerns expressed by users of different water systems and age groups may suggest the need for targeted public education strategies. These focus groups provided significant insight into the public perception of private water supplies and the need for public health outreach activities; however, to obtain a more representative understanding of the perceptions in this population, it is important that a larger scale investigation be performed.
PMCID: PMC1325020  PMID: 16336678
14.  Disinfection methods in general practice and health authority clinics: a telephone survey 
Concern about the epidemic of the acquired immune deficiency syndrome led to discussions in one health district about the dangers of cross-infection from instruments in general practice and health authority clinics. In order to establish what current disinfection practices were in use a telephone survey was adopted as a quick and easy method of data collection. Information was collected on who was responsible for disinfection as well as details of how each instrument was disinfected. Results from 69 general practices and 21 health authority clinice in one health district are reported.
Some form of sterilizer was used in 63 general practices. These included water boilers (49%), dry heat sterilizers (41%), autoclaves (5%) and pressure cookers (5%). Sixty one practices were using metal vaginal specula and of these 29 were disinfecting by boiling, three were using pressure cookers, 18 dry heat, seven chemical methods, three autoclaves and one the central sterile department of the local hospital. Of those who were boiling after simple washing, three practices boiled for five to 10 minutes and reused instruments during the same clinic. Of the 29 using simple boiling 20 (69%) were boiling for less than 20 minutes.
The study highlights the fact that no formal advice has been given on disinfection practice by the DHSS, the health authorities or the family practitioner committees. The need to set up local guidelines and develop practical steps for their introduction are discussed.
PMCID: PMC1711714  PMID: 3271009
15.  Geographical Inequalities in Use of Improved Drinking Water Supply and Sanitation across Sub-Saharan Africa: Mapping and Spatial Analysis of Cross-sectional Survey Data 
PLoS Medicine  2014;11(4):e1001626.
Using cross-sectional survey data, Rachel Pullan and colleagues map geographical inequalities in use of improved drinking water supply and sanitation across sub-Saharan Africa.
Please see later in the article for the Editors' Summary
Understanding geographic inequalities in coverage of drinking-water supply and sanitation (WSS) will help track progress towards universal coverage of water and sanitation by identifying marginalized populations, thus helping to control a large number of infectious diseases. This paper uses household survey data to develop comprehensive maps of WSS coverage at high spatial resolution for sub-Saharan Africa (SSA). Analysis is extended to investigate geographic heterogeneity and relative geographic inequality within countries.
Methods and Findings
Cluster-level data on household reported use of improved drinking-water supply, sanitation, and open defecation were abstracted from 138 national surveys undertaken from 1991–2012 in 41 countries. Spatially explicit logistic regression models were developed and fitted within a Bayesian framework, and used to predict coverage at the second administrative level (admin2, e.g., district) across SSA for 2012. Results reveal substantial geographical inequalities in predicted use of water and sanitation that exceed urban-rural disparities. The average range in coverage seen between admin2 within countries was 55% for improved drinking water, 54% for use of improved sanitation, and 59% for dependence upon open defecation. There was also some evidence that countries with higher levels of inequality relative to coverage in use of an improved drinking-water source also experienced higher levels of inequality in use of improved sanitation (rural populations r = 0.47, p = 0.002; urban populations r = 0.39, p = 0.01). Results are limited by the quantity of WSS data available, which varies considerably by country, and by the reliability and utility of available indicators.
This study identifies important geographic inequalities in use of WSS previously hidden within national statistics, confirming the necessity for targeted policies and metrics that reach the most marginalized populations. The presented maps and analysis approach can provide a mechanism for monitoring future reductions in inequality within countries, reflecting priorities of the post-2015 development agenda.
Please see later in the article for the Editors' Summary
Editors' Summary
Access to a safe drinking-water supply (a water source that is protected from contamination) and to adequate sanitation facilities (toilets, improved latrines, and other facilities that prevent people coming into contact with human urine and feces) is essential for good health. Unimproved drinking-water sources and sanitation are responsible for 85% of deaths from diarrhea and 1% of the global burden of disease. They also increase the transmission of parasitic worms and other neglected tropical diseases. In 2000, world leaders set a target of reducing the proportion of the global population without access to safe drinking water and basic sanitation to half of the 1990 level by 2015 as part of Millennium Development Goal (MDG) 7 (“Ensure environmental sustainability”; the MDGs are designed to improve the social, economic, and health conditions in the world's poorest countries). Between 1990 and 2010, more than 2 billion people gained access to improved drinking-water sources and 1.8 billion gained access to improved sanitation. In 2011, 89% of the world's population had access to an improved drinking-water supply, 1% above the MDG target, and 64% had access to improved sanitation (the MDG target is 75%).
Why Was This Study Done?
Despite these encouraging figures, the WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation (JMP) estimates that, globally, 768 million people relied on unimproved drinking-water sources, 2.5 billion people did not use an improved sanitation facility, and more than 1 billion people (15% of the global population) were defecating in the open in 2011. The JMP estimates for 2011 also reveal national and sub-national inequalities in drinking-water supply and sanitation coverage but a better understanding of geographic inequalities is needed to track progress towards universal coverage of access to improved water and sanitation and to identify the populations that need the most help to achieve this goal. Here, the researchers use cross-sectional household survey data and modern statistical approaches to produce a comprehensive map of the coverage of improved drinking-water supply and improved sanitation at high spatial resolution for sub-Saharan Africa and to investigate geographic inequalities in coverage. Cross-sectional household surveys collect health and other information from households at a single time-point, including data on use of safe water and improved sanitation.
What Did the Researchers Do and Find?
The researchers extracted data on reported household use of an improved drinking-water supply (for example, a piped water supply), improved sanitation facilities (for example, a flushing toilet), and open defecation from 138 national household surveys undertaken between 1991 and 2012 in 41 countries in sub-Saharan Africa. They developed statistical models to fit these data and used the models to estimate coverage at the district (second administrative) level across sub-Saharan Africa for 2012. For ten countries, the estimated coverage of access to improved drinking water at the district level within individual countries ranged from less than 25% to more than 75%. Within-country ranges of a similar magnitude were estimated for coverage of access to improved sanitation (21 countries) and for open defecation (16 countries). Notably, rural households in the districts with the lowest coverage of access to improved water supply and sanitation within a country were 1.5–8 times less likely to access improved drinking water, 2–18 times less likely to access improved sanitation, and 2–80 times more likely to defecate in the open than rural households in districts with the best coverage. Finally, countries with high levels of inequality in improved drinking-water source coverage also experienced high levels of inequality in improved sanitation coverage.
What Do These Findings Mean?
These findings identify important geographic inequalities in the coverage of access to improved water sources and sanitation that were previously hidden within national statistics. The accuracy of these findings depends on the accuracy of the data on water supplies and sanitation provided by household surveys, on the researchers' definitions for improved water supplies and sanitation, and on their statistical methods. Nevertheless, these findings confirm that, to achieve universal coverage of access to improved drinking-water sources and sanitation, strategies that target the areas with the lowest coverage are essential. Moreover, the maps and the analytical approach presented here provide the means for monitoring future reductions in inequalities in the coverage of access to improved water sources and sanitation and thus reflect a major priority of the post-2015 development agenda.
Additional Information
Please access these websites via the online version of this summary at
A PLOS Medicine Collection on water and sanitation is available
The World Health Organization (WHO) provides information on water, sanitation, and health (in several languages)
The WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation is the official United Nations mechanism tasked with monitoring progress toward MDG7, Target 7B; the JMP 2013 update report is available online (also available in French and Spanish through the JMP website)
The sub-national predictions resulting from this study and the final sub-national maps are available as a resource for researchers and planners
PMCID: PMC3979660  PMID: 24714528
16.  Combined Impact of Health Behaviours and Mortality in Men and Women: The EPIC-Norfolk Prospective Population Study 
PLoS Medicine  2008;5(1):e12.
There is overwhelming evidence that behavioural factors influence health, but their combined impact on the general population is less well documented. We aimed to quantify the potential combined impact of four health behaviours on mortality in men and women living in the general community.
Methods and Findings
We examined the prospective relationship between lifestyle and mortality in a prospective population study of 20,244 men and women aged 45–79 y with no known cardiovascular disease or cancer at baseline survey in 1993–1997, living in the general community in the United Kingdom, and followed up to 2006. Participants scored one point for each health behaviour: current non-smoking, not physically inactive, moderate alcohol intake (1–14 units a week) and plasma vitamin C >50 mmol/l indicating fruit and vegetable intake of at least five servings a day, for a total score ranging from zero to four. After an average 11 y follow-up, the age-, sex-, body mass–, and social class–adjusted relative risks (95% confidence intervals) for all-cause mortality(1,987 deaths) for men and women who had three, two, one, and zero compared to four health behaviours were respectively, 1.39 (1.21–1.60), 1.95 (1.70–-2.25), 2.52 (2.13–3.00), and 4.04 (2.95–5.54) p < 0.001 trend. The relationships were consistent in subgroups stratified by sex, age, body mass index, and social class, and after excluding deaths within 2 y. The trends were strongest for cardiovascular causes. The mortality risk for those with four compared to zero health behaviours was equivalent to being 14 y younger in chronological age.
Four health behaviours combined predict a 4-fold difference in total mortality in men and women, with an estimated impact equivalent to 14 y in chronological age.
From a large prospective population study, Kay-Tee Khaw and colleagues estimate the combined impact of four behaviors--not smoking, not being physically inactive, moderate alcohol intake, and at least five vegetable servings a day--amounts to 14 additional years of life.
Editors' Summary
Every day, or so it seems, new research shows that some aspect of lifestyle—physical activity, diet, alcohol consumption, and so on—affects health and longevity. For the person in the street, all this information is confusing. What is a healthy diet, for example? Although there are some common themes such as the benefit of eating plenty of fruit and vegetables, the details often differ between studies. And exactly how much physical activity is needed to improve health? Is a gentle daily walk sufficient or simply a stepping stone to doing enough exercise to make a real difference? The situation with alcohol consumption is equally confusing. Small amounts of alcohol apparently improve health but large amounts are harmful. As a result, it can be hard for public-health officials to find effective ways to encourage the behavioral changes that the scientific evidence suggests might influence the health of populations.
Why Was This Study Done?
There is another factor that is hindering official attempts to provide healthy lifestyle advice to the public. Although there is overwhelming evidence that individual behavioral factors influence health, there is very little information about their combined impact. If the combination of several small differences in lifestyle could be shown to have a marked effect on the health of populations, it might be easier to persuade people to make behavioral changes to improve their health, particularly if those changes were simple and relatively easy to achieve. In this study, which forms part of the European Prospective Investigation into Cancer and Nutrition (EPIC), the researchers have examined the relationship between lifestyle and the risk of dying using a health behavior score based on four simply defined behaviors—smoking, physical activity, alcohol drinking, and fruit and vegetable intake.
What Did the Researchers Do and Find?
Between 1993 and 1997, about 20,000 men and women aged 45–79 living in Norfolk UK, none of whom had cancer or cardiovascular disease (heart or circulation problems), completed a health and lifestyle questionnaire, had a health examination, and had their blood vitamin C level measured as part of the EPIC-Norfolk study. A health behavior score of between 0 and 4 was calculated for each participant by giving one point for each of the following healthy behaviors: current non-smoking, not physically inactive (physical inactivity was defined as having a sedentary job and doing no recreational exercise), moderate alcohol intake (1–14 units a week; a unit of alcohol is half a pint of beer, a glass of wine, or a shot of spirit), and a blood vitamin C level consistent with a fruit and vegetable intake of at least five servings a day. Deaths among the participants were then recorded until 2006. After allowing for other factors that might have affected their likelihood of dying (for example, age), people with a health behavior score of 0 were four times as likely to have died (in particular, from cardiovascular disease) than those with a score of 4. People with a score of 2 were twice as likely to have died.
What Do These Findings Mean?
These findings indicate that the combination of four simply defined health behaviors predicts a 4-fold difference in the risk of dying over an average period of 11 years for middle-aged and older people. They also show that the risk of death (particularly from cardiovascular disease) decreases as the number of positive health behaviors increase. Finally, they can be used to calculate that a person with a health score of 0 has the same risk of dying as a person with a health score of 4 who is 14 years older. These findings need to be confirmed in other populations and extended to an analysis of how these combined health behaviors affect the quality of life as well as the risk of death. Nevertheless, they strongly suggest that modest and achievable lifestyle changes could have a marked effect on the health of populations. Armed with this information, public-health officials should now be in a better position to encourage behavior changes likely to improve the health of middle-aged and older people.
Additional Information.
Please access these Web sites via the online version of this summary at
The MedlinePlus encyclopedia contains a page on healthy living (in English and Spanish)
The MedlinePlus page on seniors' health contains links to many sites dealing with healthy lifestyles and longevity (in English and Spanish)
The European Prospective Investigation into Cancer and Nutrition (EPIC) study is investigating the relationship between nutrition and lifestyle and the development of cancer and other chronic diseases; information about the EPIC-Norfolk study is also available
The US Centers for Disease Control and Prevention provides information on healthy aging for older adults, including information on health-related behaviors (in English and Spanish)
The UK charity Age Concerns provides a fact sheet about staying healthy in later life
The London Health Observatory, which provides information for policy makers and practitioners about improving health and health care, has a section on how lifestyle and behavior affect health
PMCID: PMC2174962  PMID: 18184033
17.  Risk Factors Associated with the Choice to Drink Bottled Water and Tap Water in Rural Saskatchewan 
A cross-sectional study investigated risk factors associated with choices to drink bottled water and tap water in rural Saskatchewan. Of 7,500 anonymous postal questionnaires mailed out, 2,065 responses were analyzed using generalized linear mixed models. Those who reported a water advisory (p < 0.001) or living in the area for ≤10 years (p = 0.01) were more likely to choose bottled water. Those who reported tap water was not safe to drink were more likely to choose bottled water, an effect greater for those who had no aesthetic complaints (p ≤ 0.001), while those with aesthetic complaints were more likely to choose bottled water if they believed the water was safe (p < 0.001). Respondents who treated their water and did not use a community supply were more likely to choose bottled water (p < 0.001), while those who did not treat their water were more likely to choose bottled water regardless of whether a community supply was used (p < 0.001). A similar pattern of risk factors was associated with a decreased likelihood of consuming tap water daily; however, the use of a community water supply was not significant. Understanding the factors involved in drinking water choices could inform public health education efforts regarding water management in rural areas.
PMCID: PMC3945558  PMID: 24487453
drinking water; bottled water; tap water; water treatment; water quality; risk perception; aesthetic characteristics
18.  Establishing a Federal and State Data Exchange Pilot for Public Health Situational Awareness 
U.S. Department of Health and Human Services (HHS) Office of the Assistant Secretary for Preparedness and Response (ASPR) partnered with the Florida Department of Health (FDOH), Bureau of Epidemiology, to implement a new process for the unidirectional exchange of electronic medical record (EMR) data when ASPR clinical assets are operational in the state following a disaster or other response event. The purpose of the current work was to automate the exchange of data from the ASPR electronic medical record system EMR-S into the FDOH Electronic Surveillance System for the Early Notification of Community-based Epidemics (ESSENCE-FL) system during the 2012 Republican National Convention (RNC).
ASPR deploys clinical assets, including an EMR system, to the ground per state requests during planned and no-notice events. The analysis of patient data collected by deployed federal personnel is an integral part of ASPR and FDOH’s surveillance efforts. However, this surveillance can be hampered by the logistical issues of field work in a post-disaster environment leading to delayed analysis and interpretation of these data to inform decision makers at the federal, state, and local levels. FDOH operates ESSENCE-FL, a multi-tiered, automated, and secure web-based application for analysis and visualization of clinical data. The system is accessible statewide by FDOH staff as well as by hospitals that participate in the system. To improve surveillance ASPR and FDOH engaged in a pilot project whereby EMR data from ASPR would be sent to FDOH in near real-time during the 2012 hurricane season and the 2012 RNC. This project is in direct support of Healthcare Preparedness Capability 6, Information Sharing, and Public Health Preparedness Capability 13, Public Health Surveillance and Epidemiological Investigation.
In 2011, FDOH approached ASPR about securely transmitting raw EMR data that could be ingested by ESSENCE-FL during ASPR deployments in the state. Upon conclusion of an agreement for a date exchange pilot, data elements of interest from the ASPR EMR were identified. Due to the modular design ESSENCE-FL Microsoft SQL databases were easily adapted by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) to add a new module to handle receipt of ASPR EMR data including code to process the files, remove duplicates and create associations with existing reference information, such as system-defined geographic regions and age groups. Scripts were developed to run on the ASPR server to create and send updated files via secure file transfer protocol (SFTP) every 15 minutes to ESSENCE-FL. Prior ASPR event deployment data was scrubbed and sent to ESSENCE-FL as a test dataset to ensure appropriate receipt and ingestion of the new data source.
EMR data was transmitted through a central server at ASPR to ESSENCE-FL every 15 minutes during each day of the 2012 RNC (August 26–31). In ESSENCE-FL, configuration allowed the data to be queried, analyzed, and visualized similar to existing ESSENCE-FL data sources. In all, data from 11 patient encounters were successfully exchanged between the partners. The data were used by ASPR and FDOH to simultaneously monitor in near real-time onsite medical response activities during the convention.
Timely access to patient data can enhance situational awareness and disease surveillance efforts and provide decision makers with key information in an expedient manner during disaster response and mass gatherings such as the RNC. However, data are siloed within organizations. The collaboration between FDOH, ASPR and JHU/APL made EMR data sharing and analysis more expeditious and efficient and increased timely access to these data by local, state, and federal epidemiologists. The integration of these data into the ESSENCE-FL system created one location where users could go to access data and create epidemiologic reports for a given region in Florida, including the RNC. To achieve these successes with partners in the future, it will be necessary to develop partnerships well in advance of intended data exchange. Future recommendations include robust pre-event testing of the data exchange process and planning for a greater amount of lead-time between enacting the official agreement and beginning data exchange.
PMCID: PMC3692893
Syndromic surveillance; Public health informatics; Data exchange; Federal and state collaboration
19.  Municipal water quantities and health in Nunavut households: an exploratory case study in Coral Harbour, Nunavut, Canada 
International Journal of Circumpolar Health  2014;73:10.3402/ijch.v73.23843.
Access to adequate quantities of water has a protective effect on human health and well-being. Despite this, public health research and interventions are frequently focused solely on water quality, and international standards for domestic water supply minimums are often overlooked or unspecified. This trend is evident in Inuit and other Arctic communities even though numerous transmissible diseases and bacterium infections associated with inadequate domestic water quantities are prevalent.
Our objective was to explore the pathways by which the trucked water distribution systems being used in remote northern communities are impacting health at the household level, with consideration given to the underlying social and environmental determinants shaping health in the region.
Using a qualitative case study design, we conducted 37 interviews (28 residents, 9 key informants) and a review of government water documents to investigate water usage practices and perspectives. These data were thematically analysed to understand potential health risks in Arctic communities and households.
Each resident receives an average of 110 litres of municipal water per day. Fifteen of 28 households reported experiencing water shortages at least once per month. Of those 15, most were larger households (5 people or more) with standard sized water storage tanks. Water shortages and service interruptions limit the ability of some households to adhere to public health advice. The households most resilient, or able to cope with domestic water supply shortages, were those capable of retrieving their own drinking water directly from lake and river sources. Residents with extended family and neighbours, whom they can rely on during shortages, were also less vulnerable to municipal water delays.
The relatively low in-home water quantities observed in Coral Harbour, Nunavut, appear adequate for some families. Those living in overcrowded households, however, are accessing water in quantities more typically seen in water insecure developing countries. We recommend several practical interventions and revisions to municipal water supply systems.
PMCID: PMC3970036  PMID: 24765615
Inuit; domestic water; water security; public health; overcrowded housing; built environment; communicable diseases; Canadian Arctic
20.  Adult Consequences of Late Adolescent Alcohol Consumption: A Systematic Review of Cohort Studies 
PLoS Medicine  2011;8(2):e1000413.
In a systematic review of cohort studies of adolescent drinking and later outcomes, Jim McCambridge and colleagues show that although studies suggest links to worse adult physical and mental health and social consequences, existing evidence is of poor quality.
Although important to public policy, there have been no rigorous evidence syntheses of the long-term consequences of late adolescent drinking.
Methods and Findings
This systematic review summarises evidence from general population cohort studies of drinking between 15–19 years old and any subsequent outcomes aged 20 or greater, with at least 3 years of follow-up study. Fifty-four studies were included, of which 35 were assessed to be vulnerable to bias and/or confounding. The principal findings are: (1) There is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems including dependence; (2) Although a number of studies suggest links to adult physical and mental health and social consequences, existing evidence is of insufficient quality to warrant causal inferences at this stage.
There is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden that is consequent on late adolescent drinking, both in relation to adult drinking and more broadly. Reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harms.
Please see later in the article for the Editors' Summary
Editors' Summary
The effects of alcohol intoxication (drunkenness), dependence (habitual, compulsive, and long-term drinking), and the associated biochemical changes, have wide-ranging health and social consequences, some of which can be lethal. Worldwide, alcohol causes 2.5 million deaths (3.8% of total) and 69.4 million (4.5% of total) of disability-adjusted life years (DALYs). Unintentional injuries alone account for about one-third of the 2.5 million deaths, whereas neuro-psychiatric conditions account for almost 40%. There is also a causal relationship between alcohol consumption and more than 60 types of disease and injury; worldwide, alcohol is estimated to cause about 20%–30% cases of esophageal cancer, liver cancer, cirrhosis of the liver, homicide, epilepsy, and motor vehicle crashes. There is increasing evidence that, in addition to the volume of alcohol consumed, the pattern of drinking has an effect on health outcomes, with binge drinking found to be particularly harmful. As the majority of people who binge drink are teenagers, this group may be particularly vulnerable to the damaging health effects of alcohol, leading to global concern about the drinking trends and patterns among young people.
Why Was This Study Done?
Although there have been many published cohort studies reporting the longer term harms associated with adolescent drinking, the strength of this evidence remains unclear, which has implications for the objectives of interventions. For example, if adolescent drinking does not cause later difficulties, early intervention on, and management of, the acute consequences of alcohol consumption, such as antisocial behaviour and unintentional injuries, may be the most appropriate community safety and public health responses. However, if there is a causal relationship, there needs to be an additional approach that addresses the cumulative harmful effects of alcohol. The researchers conducted this systematic review of cohort studies, as this method provides the strongest observational study design to evaluate evidence of causality.
What Did the Researchers Do and Find?
The researchers conducted a comprehensive literature review to identify relevant studies that met their inclusion criteria, which were: (1) data collection from at least two points in time, at least 3 years apart, from the same cohort; (2) data collection regarding alcohol consumption between the ages of 15 and 19 years old; and (3) inclusion of a report of at least one quantitative measure of effect, such as an odds ratio, between alcohol involvement and any later outcome assessed at age 20 or greater. The majority of these studies were multiple reports from ten cohorts and approximately half were from the US. The researchers then evaluated the strength of causal inference possible in these studies by assessing whether all possible contributing factors(confounders) had been taken into account, identifying studies that had follow-up rates of 80% or greater, and which had sample sizes of 1,000 participants or more.
Using these methods, the researchers found that, overall, there is consistent evidence that higher alcohol consumption in late adolescence continues into adulthood and is also associated with alcohol problems, including dependence. For example, one population-based cohort showed that late adolescent drinking can cause early death among men, mainly through car crashes and suicides, and there was a large evidence base supporting the ongoing impacts of late adolescent drinking on adult drinking behaviours—although most of these studies could not strongly support causal inferences because of their weak designs. The researchers also concluded that although a number of studies suggested links with late adolescent drinking to adult physical and mental health and social consequences, this evidence is generally of poor quality and insufficient to infer causality.
What Do These Findings Mean?
The results of this study show that that the evidence-base on the long-term consequences of late adolescent drinking is not as extensive or compelling as it needs to be. The researchers stress that there is an urgent need for high quality long-term prospective cohort studies in order to better understand the public health burden associated with adolescent drinking in general and in relation to adult drinking. However, there is sufficient evidence to suggest that reducing drinking during late adolescence is likely to be important for preventing long-term adverse consequences as well as protecting against more immediate harmful consequences harms.
Additional Information
Please access these Web sites via the online version of this summary at
The World Health Organization has information about the global incidence of alcohol consumption
The US-based Marin Institute has information about alcohol and young people
The BBC also has a site on late adolescent drinking
PMCID: PMC3035611  PMID: 21346802
21.  Diarrhoea prevalence in children under five years of age in rural Burundi: an assessment of social and behavioural factors at the household level 
Global Health Action  2014;7:10.3402/gha.v7.24895.
Diarrhoea is the second leading cause of child mortality worldwide. Low- and middle-income countries are particularly burdened with this both preventable and treatable condition. Targeted interventions include the provision of safe water, the use of sanitation facilities and hygiene education, but are implemented with varying local success.
To determine the prevalence of and factors associated with diarrhoea in children under five years of age in rural Burundi.
A cross-sectional survey was conducted among 551 rural households in northwestern Burundi. Areas of inquiry included 1) socio-demographic information, 2) diarrhoea period prevalence and treatment, 3) behaviour and knowledge, 4) socio-economic indicators, 5) access to water and water chain as well as 6) sanitation and personal/children's hygiene.
A total of 903 children were enrolled. The overall diarrhoea prevalence was 32.6%. Forty-six per cent (n=255) of households collected drinking water from improved water sources and only 3% (n=17) had access to improved sanitation. We found a lower prevalence of diarrhoea in children whose primary caretakers received hygiene education (17.9%), boiled water prior to its utilisation (19.4%) and were aged 40 or older (17.9%). Diarrhoea was associated with factors such as the mother's age being less than 25 and the conviction that diarrhoea could not be prevented. No gender differences were detected regarding diarrhoea prevalence or the caretaker's decision to treat.
Diarrhoea prevalence can be reduced through hygiene education and point-of use household water treatment such as boiling. In order to maximise the impact on children's health in the given rural setting, future interventions must assure systematic and regular hygiene education at the household and community level.
PMCID: PMC4141944  PMID: 25150028
developing countries; diarrhoea; prevention; control; Burundi; water supply; sanitation; hygiene; children
22.  Effectiveness of screening and brief alcohol intervention in primary care (SIPS trial): pragmatic cluster randomised controlled trial 
Objective To evaluate the effectiveness of different brief intervention strategies at reducing hazardous or harmful drinking in primary care. The hypothesis was that more intensive intervention would result in a greater reduction in hazardous or harmful drinking.
Design Pragmatic cluster randomised controlled trial.
Setting Primary care practices in the north east and south east of England and in London.
Participants 3562 patients aged 18 or more routinely presenting in primary care, of whom 2991 (84.0%) were eligible to enter the trial: 900 (30.1%) screened positive for hazardous or harmful drinking and 756 (84.0%) received a brief intervention. The sample was predominantly male (62%) and white (92%), and 34% were current smokers.
Interventions Practices were randomised to three interventions, each of which built on the previous one: a patient information leaflet control group, five minutes of structured brief advice, and 20 minutes of brief lifestyle counselling. Delivery of the patient leaflet and brief advice occurred directly after screening and brief lifestyle counselling in a subsequent consultation.
Main outcome measures The primary outcome was patients’ self reported hazardous or harmful drinking status as measured by the alcohol use disorders identification test (AUDIT) at six months. A negative AUDIT result (score <8) indicated non-hazardous or non-harmful drinking. Secondary outcomes were a negative AUDIT result at 12 months, experience of alcohol related problems (alcohol problems questionnaire), health utility (EQ-5D), service utilisation, and patients’ motivation to change drinking behaviour (readiness to change) as measured by a modified readiness ruler.
Results Patient follow-up rates were 83% at six months (n=644) and 79% at 12 months (n=617). At both time points an intention to treat analysis found no significant differences in AUDIT negative status between the three interventions. Compared with the patient information leaflet group, the odds ratio of having a negative AUDIT result for brief advice was 0.85 (95% confidence interval 0.52 to 1.39) and for brief lifestyle counselling was 0.78 (0.48 to 1.25). A per protocol analysis confirmed these findings.
Conclusions All patients received simple feedback on their screening outcome. Beyond this input, however, evidence that brief advice or brief lifestyle counselling provided important additional benefit in reducing hazardous or harmful drinking compared with the patient information leaflet was lacking.
Trial registration Current Controlled Trials ISRCTN06145674.
PMCID: PMC3541471  PMID: 23303891
23.  Bacteriological assessment of urban water sources in Khamis Mushait Governorate, southwestern Saudi Arabia 
Urban water sources of Khamis Mushait Governorate, southwestern Saudi Arabia, were studied to assess their bacteriological characteristics and suitability for potable purposes. A cross-sectional epidemiological method was adopted to investigate the four main urban water sources (i.e. bottled, desalinated, surface, and well water). These were sampled and examined between February and June 2007.
A total of 95 water samples from bottled, desalinated, surface, and well water were collected randomly from the study area using different gathering and analysing techniques. The bacteriological examination of water samples included the most probable number of presumptive coliforms, faecal coliforms, and faecal streptococci (MPN/100 ml). The results showed that the total coliform count (MPN/100 ml) was not detected in any samples taken from bottled water, while it was detected in those taken from desalinated, surface, and well water: percentages were 12.9, 80.0, and 100.0, respectively. Faecal coliforms were detected in desalinated, surface, and well water, with percentages of 3.23, 60.0 and 87.88, respectively. About 6.45% of desalinated water, 53.33% of surface water, and 57.58% of well water was found positive for faecal streptococci. Colonies of coliforms were identified in different micro-organisms with various percentages.
Water derived from traditional sources (wells) showed increases in most of the investigated bacteriological parameters, followed by surface water as compared to bottled or desalinated water. This may be attributed to the fact that well and surface water are at risk of contamination as indicated by the higher levels of most bacteriological parameters. Moreover, well water is exposed to point sources of pollution such as septic wells and domestic and farming effluents, as well as to soil with a high humus content. The lower bacteriological characteristics in samples from bottled water indicate that it is satisfactory for human drinking purposes. Contamination of desalinated water that is the main urban water source may occur during transportation from the desalination plant or in the house reservoir of the consumer. Improving and expanding the existing water treatment and sanitation systems is more likely to provide safe and sustainable sources of water over the long term. Strict hygienic measures should be applied to improve water quality and to avoid deleterious effects on public health, by using periodical monitoring programmes to detect sewage pollution running over local hydrological networks and valleys.
PMCID: PMC2672944  PMID: 19302710
24.  The Effects on Saturated Fat Purchases of Providing Internet Shoppers with Purchase- Specific Dietary Advice: A Randomised Trial 
PLoS Clinical Trials  2006;1(5):e22.
The supermarket industry now services many customers through online food shopping over the Internet. The Internet shopping process offers a novel opportunity for the modification of dietary patterns. The aim of this study was to evaluate the effects on consumers' purchases of saturated fat of a fully automated computerised system that provided real-time advice tailored to the consumers' specific purchases recommending foods lower in saturated fat.
This study was a blinded, randomised controlled trial.
The study was conducted in Sydney, New South Wales, Australia.
The participants were consumers using a commercial online Internet shopping site between February and June 2004.
Individuals assigned to intervention received fully automated advice that recommended specific switches from selected products higher in saturated fat to alternate similar products lower in saturated fat. Participants assigned to control received general non-specific advice about how to eat a diet lower in saturated fat.
Outcome Measures:
The outcome measure was the difference in saturated fat (grams per 100 g of food) in shopping baskets between the intervention and control groups.
There were 497 randomised participants, mean age 40 y, each shopping for an average of about three people. The amount of saturated fat in the foods purchased by the intervention group was 0.66% lower (95% confidence interval 0.48–0.84, p < 0.001) than in the control group. The effects of the intervention were sustained over consecutive shopping episodes, and there was no difference in the average cost of the food bought by each group.
Fully automated, purchase-specific dietary advice offered to customers during Internet shopping can bring about changes in food purchasing habits that are likely to have significant public health implications. Because implementation is simple to initiate and maintain, this strategy would likely be highly cost-effective.
Editorial Commentary
Background: Current evidence from randomized trials and observational studies indicates that people in the developed world should try to lower their intake of saturated fat, in order to reduce the risk of cardiovascular diseases such as heart attacks and strokes. However, achieving this aim in the population is not straightforward, partly because of the high cost of personalized interventions and, often, their limited success. One possible way of delivering dietary advice that might help people to make healthier food choices is through Internet shopping systems. In the trial reported here, which was carried out in Sydney, New South Wales, Australia, people using an Internet food shopping system and who were about to complete their purchases were offered the chance to participate in the trial. If they agreed, participants were immediately randomized to receive either general dietary advice (the trial's control) or tailored advice delivered by a computer program that prompted shoppers to replace specific items in their shopping basket with alternatives lower in saturated fat. The main outcome the trial researchers were interested in was the percent of saturated fat in the food bought, compared between the two arms of the trial. The researchers also looked at the cost per gram of the food that was bought.
What this trial shows: The researchers recruited 456 participants into the trial. They found that the participants who received tailored advice bought foods containing less saturated fat, on average, than the participants who received only general advice. The difference between the two groups amounted to around 10% of the average quantity of saturated fat in food chosen before the advice was offered, and this difference was statistically significant. Finally, there was no significant difference in the average cost of food between the two arms of the trial.
Strengths and limitations: The trial recruited enough participants to evaluate whether this intervention had an effect on the main outcomes, and the randomization procedures used and outcomes measured were appropriate. A potential strength of this study is that it evaluates a low-cost technology that might be useful alongside other strategies for reducing saturated fat intake. However, the trial was conducted among people who are technically aware, and may not therefore represent the general population as a whole. In the trial, the outcomes measured were limited to information about the foods bought, and the effects on cardiovascular risk or health outcomes were not examined.
Contribution to the evidence: Systematic reviews of existing randomized trials already show that offering dietary advice can bring about improvements in diet (such as saturated fat intake) and cardiovascular risk. This trial adds to that evidence by showing that tailored advice such as can be delivered via an Internet shopping system is likely to be a useful method of encouraging healthier food purchases.
PMCID: PMC1574360  PMID: 17013429
25.  Living Alone and Alcohol-Related Mortality: A Population-Based Cohort Study from Finland 
PLoS Medicine  2011;8(9):e1001094.
Kimmo Herttua and colleagues showed that living alone is associated with a substantially increased risk of alcohol-related mortality, irrespective of gender, socioeconomic status, or cause of death, and that this effect was exacerbated after a price reduction in alcohol in 2004.
Social isolation and living alone are increasingly common in industrialised countries. However, few studies have investigated the potential public health implications of this trend. We estimated the relative risk of death from alcohol-related causes among individuals living alone and determined whether this risk changed after a large reduction in alcohol prices.
Methods and Findings
We conducted a population-based natural experimental study of a change in the price of alcohol that occurred because of new laws enacted in Finland in January and March of 2004, utilising national registers. The data are based on an 11% sample of the Finnish population aged 15–79 y supplemented with an oversample of deaths. The oversample covered 80% of all deaths during the periods January 1, 2000–December 31, 2003 (the four years immediately before the price reduction of alcohol), and January 1, 2004–December 31, 2007 (the four years immediately after the price reduction). Alcohol-related mortality was defined using both underlying and contributory causes of death. During the 8-y follow-up about 18,200 persons died due to alcohol-related causes. Among married or cohabiting people the increase in alcohol-related mortality was small or non-existing between the periods 2000–2003 and 2004–2007, whereas for those living alone, this increase was substantial, especially in men and women aged 50–69 y. For liver disease in men, the most common fatal alcohol-related disease, the age-adjusted risk ratio associated with living alone was 3.7 (95% confidence interval 3.3, 4.1) before and 4.9 (95% CI 4.4, 5.4) after the price reduction (p<0.001 for difference in risk ratios). In women, the corresponding risk ratios were 1.7 (95% CI 1.4, 2.1) and 2.4 (95% CI 2.0, 2.9), respectively (p ≤ 0.01). Living alone was also associated with other mortality from alcohol-related diseases (range of risk ratios 2.3 to 8.0) as well as deaths from accidents and violence with alcohol as a contributing cause (risk ratios between 2.1 and 4.7), both before and after the price reduction.
Living alone is associated with a substantially increased risk of alcohol-related mortality, irrespective of gender, socioeconomic status, or the specific cause of death. The greater availability of alcohol in Finland after legislation-instituted price reductions in the first three months of 2004 increased in particular the relative excess in fatal liver disease among individuals living alone.
Please see later in the article for the Editors' Summary
Editors' Summary
Throughout most of human history, people have lived in tight-knit communities where there was likely to be someone to turn to for help, advice, or company. But the modern way of life in industrialized countries is greatly reducing the quantity and quality of social relationships. Instead of living in extended families, many people now live miles away from their relatives, often living and working alone. Others commute long distances to work, which leaves little time for socializing with friends or relatives. And many delay or forgo getting married and having children. Consequently, loneliness and social isolation are getting more common. In the UK, according to a recent survey by the Mental Health Foundation, 10% of people often feel lonely, a third have a close friend or relative who they think is very lonely, and half think people are getting lonelier in general. Similarly, over the past two decades, there has been a three-fold increase in the number of Americans who say they have no close confidants.
Why Was This Study Done?
Some experts think that loneliness is bad for human health. They point to studies that show that people with fewer social relationships die earlier on average than people with more social relationships. But does loneliness increase the risk of dying from specific causes? It is important to investigate the relationship between loneliness and cause-specific mortality (death) because, if for example, loneliness increases the risk of dying from alcohol-related causes (heavy drinking causes liver and heart damage, increases the risk of some cancers, contributes to depression, and increases the risk of death by violence or accident), doctors could advise their patients who live alone about safe drinking. But, although loneliness is recognized as both a contributor to and a consequence of alcohol abuse, there have been no large, population-based studies on the association between living alone and alcohol-related mortality. In this population-based study, the researchers estimate the association between living alone (an indicator of a lack of social relationships) and death from alcohol-related causes in Finland for four years before and four years after an alcohol price reduction in 2004 that increased alcohol consumption.
What Did the Researchers Do and Find?
The researchers obtained information on about 80% of all people who died in Finland between 2000 and 2007 from Statistics Finland, which collects official Finnish statistics. During this period, about 18,200 people (two-thirds of whom lived alone) died from underlying alcohol-related causes (for example, liver disease and alcoholic poisoning) or contributory alcohol-related causes (for example, accidents, violence, and cardiovascular disease, with alcohol as a contributing cause). Among married and cohabiting people, the rate of alcohol-related mortality was similar in 2000–2003 and 2004–2007 but for people living alone (particularly those aged 50–69 years) the 2004 alcohol price reduction substantially increased the alcohol-related mortality rate. For liver disease in men, the risk ratio associated with living alone was 3.7 before and 4.9 after the price reduction. That is, between 2000 and 2003, men living alone were 3.7 times more likely to die of liver disease than married or cohabiting men; between 2004 and 2007, they were 4.9 times more likely to die of liver disease. In women, the corresponding risk ratios for liver disease were 1.7 and 2.4, respectively. Living alone was also associated with an increased risk of dying from other alcohol-related diseases and accidents and violence both before and after the price reduction.
What Do These Findings Mean?
These findings indicate that, in Finland, living alone is associated with an increased risk of alcohol-related mortality. Because of the study design, it is impossible to say whether living alone is a cause or a consequence of alcohol abuse, but the greater increase in alcohol-related deaths (particularly fatal liver disease) among people living alone compared to married and cohabiting people after the alcohol price reduction suggests that people living alone are more vulnerable to the adverse effects of increased alcohol availability. Further research in other countries is now needed to identify whether living alone is a cause or effect of alcohol abuse and to extend these findings to cultures where the pattern of alcohol consumption is different. However, the findings of this natural experiment suggest that living alone should be regarded as a potential risk marker for death from alcohol-related causes.
Additional Information
Please access these websites via the online version of this summary at
The Mental Health America Live Your Life Well webpage includes information about how social relationships improve mental and physical health
The Mental Health Foundation (a UK charity) presents the report The Lonely Society?
The US National Institute on Alcohol Abuse and Alcoholism has information about alcohol and its effects on health
The US Centers for Disease Control and Prevention has a website on alcohol and public health that includes information on the health risks of excessive drinking
The UK National Health Service Choices website provides detailed information about drinking and alcohol, including information on the risks of drinking too much, and personal stories about alcohol problems, including stories from people living alone (My drinks diary shock and I used to drink all day)
MedlinePlus provides links to many other resources on alcohol
PMCID: PMC3176753  PMID: 21949642

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