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1.  In an interconnected world: joint research priorities for the environment, agriculture and infectious disease 
In 2008 the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) commissioned ten think-tanks to work on disease-specific and thematic reference groups to identify top research priorities that would advance the research agenda on infectious diseases of poverty, thus contributing to improvements in human health. The first of the thematic reference group reports – on environment, agriculture and infectious diseases of poverty – was recently released. In this article we review, from an insider perspective, the strengths and weaknesses of this thematic reference group report and highlight key messages for policy-makers, funders and researchers.
doi:10.1186/2049-9957-3-2
PMCID: PMC3906909  PMID: 24472225
Agriculture; Environment; Infectious disease; Research priorities; TDR
2.  Earth as humans’ habitat: global climate change and the health of populations 
Human-induced climate change, with such rapid and continuing global-scale warming, is historically unprecedented and signifies that human pressures on Earth’s life-supporting natural systems now exceed the planet’s bio-geo-capacity. The risks from climate change to health and survival in populations are diverse, as are the social and political ramifications. Although attributing observed health changes in a population to the recent climatic change is difficult, a coherent pattern of climate- and weather-associated changes is now evident in many regions of the world. The risks impinge unevenly, especially on poorer and vulnerable regions, and are amplified by pre-existing high rates of climate-sensitive diseases and conditions. If, as now appears likely, the world warms by 3-5oC by 2100, the health consequences, directly and via massive social and economic disruption, will be severe. The health sector has an important message to convey, comparing the health risks and benefits of enlightened action to avert climate change and to achieve sustainable ways of living versus the self-interested or complacent inaction.
doi:10.15171/ijhpm.2014.03
PMCID: PMC3937947  PMID: 24596901
Climate Change; Sustainability; Population Health; Anthropocene
3.  Impediments to Comprehensive Research on Climate Change and Health 
During every climatic era Life on Earth is constrained by a limited range of climatic conditions, outside which thriving and then surviving becomes difficult. This applies at both planetary and organism (species) levels. Further, many causal influences of climate change on human health entail changes—often disruptive, sometimes irreversible—in complex system functioning. Understanding the diverse health risks from climate change, and their influence pathways, presents a challenge to environmental health researchers whose prior work has been in a more definable, specific and quantitative milieu. Extension of the research agenda and conceptual framework to assess present and future health risks from climate change may be constrained by three factors: (i) lack of historically-informed understanding of population-health sensitivity to climatic changes; (ii) an instinctual ‘epidemiologising’ tendency to choose research topics amenable to conventional epidemiological analysis and risk estimation; and (iii) under-confidence in relation to interdisciplinary collaborative scenario-based modeling of future health risks. These constraints must be recognized and remedied. And environmental researchers must argue for heightened public attention to today’s macro-environmental threats to present and future population health—emphasising the ecological dimension of these determinants of long-term health that apply to whole populations and communities, not just to individuals and social groupings.
doi:10.3390/ijerph10116096
PMCID: PMC3863889  PMID: 24225646
climate change; health; public health; research; history; modeling; policy; Goldilocks
4.  A multi-layered governance framework for incorporating social science insights into adapting to the health impacts of climate change 
Global Health Action  2013;6:10.3402/gha.v6i0.21820.
Background
Addressing climate change and its associated effects is a multi-dimensional and ongoing challenge. This includes recognizing that climate change will affect the health and wellbeing of all populations over short and longer terms, albeit in varied ways and intensities. That recognition has drawn attention to the need to take adaptive actions to lessen adverse impacts over the next few decades from unavoidable climate change, particularly in developing country settings. A range of sectors is responsible for appropriate adaptive policies and measures to address the health risks of climate change, including health services, water and sanitation, trade, agriculture, disaster management, and development.
Objectives
To broaden the framing of governance and decision-making processes by using innovative methods and assessments to illustrate the multi-sectoral nature of health-related adaptation to climate change. This is a shift from sector-specific to multi-level systems encompassing sectors and actors, across temporal and spatial scales.
Design
A review and synthesis of the current knowledge in the areas of health and climate change adaptation governance and decision-making processes.
Results
A novel framework is presented that incorporates social science insights into the formulation and implementation of adaptation activities and policies to lessen the health risks posed by climate change.
Conclusion
Clarification of the roles that different sectors, organizations, and individuals occupy in relation to the development of health-related adaptation strategies will facilitate the inclusion of health and wellbeing within multi-sector adaptation policies, thereby strengthening the overall set of responses to minimize the adverse health effects of climate change.
doi:10.3402/gha.v6i0.21820
PMCID: PMC3772341  PMID: 24028938
climate change adaptation; global health; multi-sectoral; social networks; governance; social sciences; methods
5.  Determinants of workplace injury among Thai Cohort Study participants 
BMJ Open  2013;3(7):e003079.
Objectives
To explore individual determinants of workplace injury among Thai workers.
Design
Cross-sectional analysis of a large national cohort.
Setting
Thailand.
Participants
Thai Cohort Study participants who responded to the 2009 follow-up survey were included if they reported doing paid work or being self-employed (n=51 751).
Outcome measures
Self-reported injury incidence over the past 12 months was calculated. Multivariate logistic regression models were used to test associations between individual determinants and self-reported workplace injury.
Results
Workplace injuries were reported by 1317 study participants (2.5%); the incidence was 34 (95% CI 32 to 36)/1000 worker-years for men, and 18 (17–20) for women. Among men working ≥41 h and earning <10 000 Baht, the injury rate was four times higher compared with men working <11 h and earning ≥20 001 Baht; differences in injury rates were less pronounced in women. Multivariate modelling showed that working ≥49 h/week (23%) and working for ≤10 000 Bath/month (37%) were associated with workplace injury. The increase in injury risk with increased working hours did not exceed the risk expected from increased exposure.
Conclusions
Reductions in occupational injury rates could be achieved by limiting working hours to 48/week. Particularly for Thai low wage earners and those with longer workdays, there is a need for effective injury preventive programmes.
doi:10.1136/bmjopen-2013-003079
PMCID: PMC3717462  PMID: 23869104
OCCUPATIONAL & INDUSTRIAL MEDICINE; PUBLIC HEALTH; EPIDEMIOLOGY
6.  Land-Use Change and Emerging Infectious Disease on an Island Continent 
A more rigorous and nuanced understanding of land-use change (LUC) as a driver of emerging infectious disease (EID) is required. Here we examine post hunter-gatherer LUC as a driver of infectious disease in one biogeographical region with a compressed and documented history—continental Australia. We do this by examining land-use and native vegetation change (LUCC) associations with infectious disease emergence identified through a systematic (1973–2010) and historical (1788–1973) review of infectious disease literature of humans and animals. We find that 22% (20) of the systematically reviewed EIDs are associated with LUCC, most frequently where natural landscapes have been removed or replaced with agriculture, plantations, livestock or urban development. Historical clustering of vector-borne, zoonotic and environmental disease emergence also follows major periods of extensive land clearing. These advanced stages of LUCC are accompanied by changes in the distribution and density of hosts and vectors, at varying scales and chronology. This review of infectious disease emergence in one continent provides valuable insight into the association between accelerated global LUC and concurrent accelerated infectious disease emergence.
doi:10.3390/ijerph10072699
PMCID: PMC3734451  PMID: 23812027
emerging infectious disease; zoonoses; wildlife; livestock; vector; environment; land-use; Australia
7.  Health risk factors and the incidence of hypertension: 4-year prospective findings from a national cohort of 60 569 Thai Open University students 
BMJ Open  2013;3(6):e002826.
Objective
This study evaluates the impact of a number of demographic, biological, behavioural and lifestyle health risk factors on the incidence of hypertension in Thailand over a 4-year period.
Design
A 4-year prospective study of health risk factors and their effects on the incidence of hypertension in a national Thai Cohort Study from 2005 to 2009.
Setting
As Thailand is transitioning from a developing to a middle-income developed country, chronic diseases (particularly cardiovascular disease) have emerged as major health issues. Hypertension is a major risk factor for heart attack and stroke and cross-sectional studies have indicated that the prevalence is increasing.
Study participants
A total of 57 558 Sukhothai Thammathirat Open University students who participated in both the 2005 and 2009 questionnaire surveys and who were normotensive in 2005 were included in the analysis.
Measures
Adjusted relative risks associating each risk factor and incidence of hypertension by sex, after controlling for confounders such as age, socioeconomic status, body mass index (BMI) and underlying diseases.
Results
The overall 4-year incidence of hypertension was 3.5%, with the rate in men being remarkably higher than that in women (5.2% vs 2.1%). In both sexes, hypertension was associated with age, higher BMI and comorbidities but not with income and education. In men, hypertension was associated with physical inactivity, smoking, alcohol and fast food intake. In women, hypertension was related to having a partner.
Conclusions
In both men and women, hypertension was strongly associated with age, obesity and comorbidities while it had no association with socioeconomic factors. The cohort patterns of socioeconomy and hypertension reflect that the health risk transition in Thais is likely to be at the middle stage. Diet and lifestyle factors associate with incidence of hypertension in Thais and may be amenable targets for hypertension control programmes.
doi:10.1136/bmjopen-2013-002826
PMCID: PMC3696868  PMID: 23801711
8.  Climate change threats to population health and well-being: the imperative of protective solutions that will last 
Global Health Action  2013;6:10.3402/gha.v6i0.20816.
Background
The observational evidence of the impacts of climate conditions on human health is accumulating. A variety of direct, indirect, and systemically mediated health effects have been identified. Excessive daily heat exposures create direct effects, such as heat stroke (and possibly death), reduce work productivity, and interfere with daily household activities. Extreme weather events, including storms, floods, and droughts, create direct injury risks and follow-on outbreaks of infectious diseases, lack of nutrition, and mental stress. Climate change will increase these direct health effects. Indirect effects include malnutrition and under-nutrition due to failing local agriculture, spread of vector-borne diseases and other infectious diseases, and mental health and other problems caused by forced migration from affected homes and workplaces. Examples of systemically mediated impacts on population health include famine, conflicts, and the consequences of large-scale adverse economic effects due to reduced human and environmental productivity. This article highlights links between climate change and non-communicable health problems, a major concern for global health beyond 2015.
Discussion
Detailed regional analysis of climate conditions clearly shows increasing temperatures in many parts of the world. Climate modelling indicates that by the year 2100 the global average temperature may have increased by 3-4°C unless fundamental reductions in current global trends for greenhouse gas emissions are achieved. Given other unforeseeable environmental, social, demographic, and geopolitical changes that may occur in a plus-4-degree world, that scenario may comprise a largely uninhabitable world for millions of people and great social and military tensions.
Conclusion
It is imperative that we identify actions and strategies that are effective in reducing these increasingly likely threats to health and well-being. The fundamental preventive strategy is, of course, climate change mitigation by significantly reducing global greenhouse gas emissions, especially long-acting carbon dioxide (CO2), and by increasing the uptake of CO2 at the earth's surface. This involves urgent shifts in energy production from fossil fuels to renewable energy sources, energy conservation in building design and urban planning, and reduced waste of energy for transport, building heating/cooling, and agriculture. It would also involve shifts in agricultural production and food systems to reduce energy and water use particularly in meat production. There is also potential for prevention via mitigation, adaptation, or resilience building actions, but for the large populations in tropical countries, mitigation of climate change is required to achieve health protection solutions that will last.
doi:10.3402/gha.v6i0.20816
PMCID: PMC3617647  PMID: 23561024
climate change; health; well-being; adaptation; mitigation
9.  Heat stress, health and well-being: findings from a large national cohort of Thai adults 
BMJ Open  2012;2(6):e001396.
Objectives
This study aims to examine the association between self-reported heat stress interference with daily activities (sleeping, work, travel, housework and exercise) and three graded-holistic health and well-being outcomes (energy, emotions and life satisfaction).
Design
A cross-sectional study.
Setting
The setting is tropical and developing countries as Thailand, where high temperature and high humidity are common, particularly during the hottest seasons.
Participants
This study is based on an ongoing national Thai Cohort Study of distance-learning open-university adult students (N=60 569) established in 2005 to study the health-risk transition.
Primary and secondary outcome measures
Health impacts from heat stress in our study are categorised as physical health impacts (energy levels), mental health impacts (emotions) and well-being (life satisfaction). For each health and well-being outcome we report ORs and 95% CIs using multinomial logistic regression adjusting for a wide array of potential confounders.
Results
Negative health and well-being outcomes (low-energy level, emotional problems and low life satisfaction) associated with increasing frequency of heat stress interfering with daily activities. Adjusted ORs for emotional problems were between 1.5 and 4.8 and in general worse than energy level (between 1.31 and 2.91) and life satisfaction (between 1.10 and 2.49). The worst health outcomes were when heat interfered with sleeping, followed by interference with daily travel, work, housework and exercise.
Conclusions
In tropical Thailand there already are substantial heat stress impacts on health and well-being. Increasing temperatures from climate change plus the ageing and urbanisation of the population could significantly worsen the situation. There is a need to improve public health surveillance and public awareness regarding the risks of heat stress in daily life.
doi:10.1136/bmjopen-2012-001396
PMCID: PMC3532977  PMID: 23135538
Occupational & Industrial Medicine; Epidemiology
10.  Planetary Stewardship in an Urbanizing World: Beyond City Limits 
Ambio  2012;41(8):787-794.
Cities are rapidly increasing in importance as a major factor shaping the Earth system, and therefore, must take corresponding responsibility. With currently over half the world’s population, cities are supported by resources originating from primarily rural regions often located around the world far distant from the urban loci of use. The sustainability of a city can no longer be considered in isolation from the sustainability of human and natural resources it uses from proximal or distant regions, or the combined resource use and impacts of cities globally. The world’s multiple and complex environmental and social challenges require interconnected solutions and coordinated governance approaches to planetary stewardship. We suggest that a key component of planetary stewardship is a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could increase their capacity to effect change and foster stewardship at the planetary scale and also increase their resource security.
doi:10.1007/s13280-012-0353-7
PMCID: PMC3492563  PMID: 23076974
Urban; Rural; Resources; Sustainability; Planetary stewardship; Global; Governance
11.  An Ill Wind? Climate Change, Migration, and Health 
Environmental Health Perspectives  2012;120(5):646-654.
Background: Climate change is projected to cause substantial increases in population movement in coming decades. Previous research has considered the likely causal influences and magnitude of such movements and the risks to national and international security. There has been little research on the consequences of climate-related migration and the health of people who move.
Objectives: In this review, we explore the role that health impacts of climate change may play in population movements and then examine the health implications of three types of movements likely to be induced by climate change: forcible displacement by climate impacts, resettlement schemes, and migration as an adaptive response.
Methods: This risk assessment draws on research into the health of refugees, migrants, and people in resettlement schemes as analogs of the likely health consequences of climate-related migration. Some account is taken of the possible modulation of those health risks by climate change.
Discussion: Climate-change–related migration is likely to result in adverse health outcomes, both for displaced and for host populations, particularly in situations of forced migration. However, where migration and other mobility are used as adaptive strategies, health risks are likely to be minimized, and in some cases there will be health gains.
Conclusions: Purposeful and timely policy interventions can facilitate the mobility of people, enhance well-being, and maximize social and economic development in both places of origin and places of destination. Nevertheless, the anticipated occurrence of substantial relocation of groups and communities will underscore the fundamental seriousness of human-induced climate change.
doi:10.1289/ehp.1104375
PMCID: PMC3346786  PMID: 22266739
climate change; displacement; health; migration; resettlement
12.  Governing for a Healthy Population: Towards an Understanding of How Decision-Making Will Determine Our Global Health in a Changing Climate 
Enhancing the adaptive capacity of individuals, communities, institutions and nations is pivotal to protecting and improving human health and well-being in the face of systemic social inequity plus dangerous climate change. However, research on the determinants of adaptive capacity in relation to health, particularly concerning the role of governance, is in its infancy. This paper highlights the intersections between global health, climate change and governance. It presents an overview of these key concerns, their relation to each other, and the potential that a greater understanding of governance may present opportunities to strengthen policy and action responses to the health effects of climate change. Important parallels between addressing health inequities and sustainable development practices in the face of global environmental change are also highlighted. We propose that governance can be investigated through two key lenses within the earth system governance theoretical framework; agency and architecture. These two governance concepts can be evaluated using methods of social network research and policy analysis using case studies and is the subject of further research.
doi:10.3390/ijerph9010055
PMCID: PMC3315069  PMID: 22470278
global health; climate change; adaptive capacity; equity; governance; decision-making
13.  Vulnerable populations in the Arctic 
Global Health Action  2011;4:10.3402/gha.v4i0.11210.
doi:10.3402/gha.v4i0.11210
PMCID: PMC3223415  PMID: 22121341
14.  Non-heat related impacts of climate change on working populations 
Global Health Action  2010;3:10.3402/gha.v3i0.5640.
Environmental and social changes associated with climate change are likely to have impacts on the well-being, health, and productivity of many working populations across the globe. The ramifications of climate change for working populations are not restricted to increases in heat exposure. Other significant risks to worker health (including physical hazards from extreme weather events, infectious diseases, under-nutrition, and mental stresses) may be amplified by future climate change, and these may have substantial impacts at all scales of economic activity. Some of these risks are difficult to quantify, but pose a substantial threat to the viability and sustainability of some working populations. These impacts may occur in both developed and developing countries, although the latter category is likely to bear the heaviest burden.
This paper explores some of the likely, non-heat-related health issues that climate change will have on working populations around the globe, now and in the future. These include exposures to various infectious diseases (vector-borne, zoonotic, and person-to-person), extreme weather events, stress and mental health issues, and malnutrition.
doi:10.3402/gha.v3i0.5640
PMCID: PMC3009583  PMID: 21191440
climate change; workers; vector-borne diseases; zoonoses; mental health; malnutrition; emergency workers; farmers
15.  Paleoclimate and bubonic plague: a forewarning of future risk? 
BMC Biology  2010;8:108.
Pandemics of bubonic plague have occurred in Eurasia since the sixth century ad. Climatic variations in Central Asia affect the population size and activity of the plague bacterium's reservoir rodent species, influencing the probability of human infection. Using innovative time-series analysis of surrogate climate records spanning 1,500 years, a study in BMC Biology concludes that climatic fluctuations may have influenced these pandemics. This has potential implications for health risks from future climate change.
See research article http://www.biomedcentral.com/1741-7007/8/112
doi:10.1186/1741-7007-8-108
PMCID: PMC2929224  PMID: 24576348
17.  Epidemiology, Public Health, and the Rhetoric of False Positives 
Environmental Health Perspectives  2009;117(12):1809-1813.
Background
As an observational science, epidemiology is regarded by some researchers as inherently flawed and open to false results. In a recent paper, Boffetta et al. [Boffetta P, McLaughlin JK, LaVecchia C, Tarone RE, Lipworth L, Blot WJ. False-positive results in cancer epidemiology: a plea for epistemological modesty. J Natl Cancer Inst 100:988–995 (2008)] argued that “epidemiology is particularly prone to the generation of false-positive results.” They also said “the tendency to emphasize and over-interpret what appear to be new findings is commonplace, perhaps in part because of a belief that the findings provide information that may ultimately improve public health” and that “this tendency to hype new findings increases the likelihood of downplaying inconsistencies within the data or any lack of concordance with other sources of evidence.” The authors supported these serious charges against epidemiology and epidemiologists with few examples. Although we acknowledge that false positives do occur, we view the position of Boffetta and colleagues on false positives as unbalanced and potentially harmful to public health.
Objective
We aim to provide a more balanced evaluation of epidemiology and its contribution to public health discourse.
Discussion
Boffetta and colleagues ignore the fact that false negatives may arise from the very processes that they tout as generating false-positive results. We further disagree with their proposition that false-positive results from a single study will lead to faulty decision making in matters of public health importance. In practice, such public health evaluations are based on all the data available from all relevant disciplines and never to our knowledge on a single study.
Conclusions
The lack of balance by Boffetta and colleagues in their evaluation of the impact of false-positive findings on epidemiology, the charge that “methodological vigilance is often absent” in epidemiologists’ interpretation of their own results, and the false characterization of how epidemiologic findings are used in societal decision making all undermine a major source of information regarding disease risks. We reaffirm the importance of epidemiologic evidence as a critical component of the foundation of public health protection.
doi:10.1289/ehp.0901194
PMCID: PMC2799452  PMID: 20049197
epidemiologic methods; false negatives; false positives; hyped findings
18.  Environmental change, climate and population health: a challenge for inter-disciplinary research 
doi:10.1007/s12199-008-0031-3
PMCID: PMC2698234  PMID: 19568904
Climate change; Environmental health; Global environmental change; Research needs; Sustainability
19.  Climate Variability, Social and Environmental Factors, and Ross River Virus Transmission: Research Development and Future Research Needs 
Environmental Health Perspectives  2008;116(12):1591-1597.
Background
Arbovirus diseases have emerged as a global public health concern. However, the impact of climatic, social, and environmental variability on the transmission of arbovirus diseases remains to be determined.
Objective
Our goal for this study was to provide an overview of research development and future research directions about the interrelationship between climate variability, social and environmental factors, and the transmission of Ross River virus (RRV), the most common and widespread arbovirus disease in Australia.
Methods
We conducted a systematic literature search on climatic, social, and environmental factors and RRV disease. Potentially relevant studies were identified from a series of electronic searches.
Results
The body of evidence revealed that the transmission cycles of RRV disease appear to be sensitive to climate and tidal variability. Rainfall, temperature, and high tides were among major determinants of the transmission of RRV disease at the macro level. However, the nature and magnitude of the interrelationship between climate variability, mosquito density, and the transmission of RRV disease varied with geographic area and socioenvironmental condition. Projected anthropogenic global climatic change may result in an increase in RRV infections, and the key determinants of RRV transmission we have identified here may be useful in the development of an early warning system.
Conclusions
The analysis indicates that there is a complex relationship between climate variability, social and environmental factors, and RRV transmission. Different strategies may be needed for the control and prevention of RRV disease at different levels. These research findings could be used as an additional tool to support decision making in disease control/surveillance and risk management.
doi:10.1289/ehp.11680
PMCID: PMC2599750  PMID: 19079707
climate variability; early warning system; Ross River virus transmission; social and environmental factors
20.  Weather Variability, Tides, and Barmah Forest Virus Disease in the Gladstone Region, Australia 
Environmental Health Perspectives  2005;114(5):678-683.
In this study we examined the impact of weather variability and tides on the transmission of Barmah Forest virus (BFV) disease and developed a weather-based forecasting model for BFV disease in the Gladstone region, Australia. We used seasonal autoregressive integrated moving-average (SARIMA) models to determine the contribution of weather variables to BFV transmission after the time-series data of response and explanatory variables were made stationary through seasonal differencing. We obtained data on the monthly counts of BFV cases, weather variables (e.g., mean minimum and maximum temperature, total rainfall, and mean relative humidity), high and low tides, and the population size in the Gladstone region between January 1992 and December 2001 from the Queensland Department of Health, Australian Bureau of Meteorology, Queensland Department of Transport, and Australian Bureau of Statistics, respectively. The SARIMA model shows that the 5-month moving average of minimum temperature (β = 0.15, p-value < 0.001) was statistically significantly and positively associated with BFV disease, whereas high tide in the current month (β = −1.03, p-value = 0.04) was statistically significantly and inversely associated with it. However, no significant association was found for other variables. These results may be applied to forecast the occurrence of BFV disease and to use public health resources in BFV control and prevention.
doi:10.1289/ehp.8568
PMCID: PMC1459919  PMID: 16675420
Barmah Forest virus; control; forecasting; Gladstone region; risk factors; time series modeling
21.  Nonstationary Influence of El Niño on the Synchronous Dengue Epidemics in Thailand 
PLoS Medicine  2005;2(4):e106.
Background
Several factors, including environmental and climatic factors, influence the transmission of vector-borne diseases. Nevertheless, the identification and relative importance of climatic factors for vector-borne diseases remain controversial. Dengue is the world's most important viral vector-borne disease, and the controversy about climatic effects also applies in this case. Here we address the role of climate variability in shaping the interannual pattern of dengue epidemics.
Methods and Findings
We have analysed monthly data for Thailand from 1983 to 1997 using wavelet approaches that can describe nonstationary phenomena and that also allow the quantification of nonstationary associations between time series. We report a strong association between monthly dengue incidence in Thailand and the dynamics of El Niño for the 2–3-y periodic mode. This association is nonstationary, seen only from 1986 to 1992, and appears to have a major influence on the synchrony of dengue epidemics in Thailand.
Conclusion
The underlying mechanism for the synchronisation of dengue epidemics may resemble that of a pacemaker, in which intrinsic disease dynamics interact with climate variations driven by El Niño to propagate travelling waves of infection. When association with El Niño is strong in the 2–3-y periodic mode, one observes high synchrony of dengue epidemics over Thailand. When this association is absent, the seasonal dynamics become dominant and the synchrony initiated in Bangkok collapses.
In Thailand, dengue transmission patterns are complex, with El Nino showing an association with some epidemics only; other reasons will need to be found for the initiation of other outbreaks
doi:10.1371/journal.pmed.0020106
PMCID: PMC1087219  PMID: 15839751
22.  Climate change and risk to health 
BMJ : British Medical Journal  2004;329(7480):1416-1417.
PMCID: PMC535953  PMID: 15604161
23.  Effect of influenza vaccination on excess deaths occurring during periods of high circulation of influenza: cohort study in elderly people 
BMJ : British Medical Journal  2004;329(7467):660.
Objective To estimate the protection against death provided by vaccination against influenza.
Design Prospective cohort follow up supplemented by weekly national counts of influenza confirmed in the community.
Setting Primary care.
Participants 24 535 patients aged over 75 years from 73 general practices in Great Britain.
Main outcome measure Death.
Results In unvaccinated members of the cohort daily all cause mortality was strongly associated with an index of influenza circulating in the population (mortality ratio 1.16, 95% confidence interval 1.04 to 1.29 at 90th centile of circulating influenza). The association was strongest for respiratory deaths but was also present for cardiovascular deaths. In contrast, in vaccinated people mortality from any cause was not associated with circulating influenza. The difference in patterns between vaccinated and unvaccinated people could not easily be due to chance (P = 0.02, all causes).
Conclusions This study, using a novel and robust approach to control for confounding, provides robust evidence of a protective effect on mortality of vaccination against influenza.
doi:10.1136/bmj.38198.594109.AE
PMCID: PMC517645  PMID: 15313884
24.  Vulnerability to winter mortality in elderly people in Britain: population based study 
BMJ : British Medical Journal  2004;329(7467):647.
Objective To examine the determinants of vulnerability to winter mortality in elderly British people.
Design Population based cohort study (119 389 person years of follow up).
Setting 106 general practices from the Medical Research Council trial of assessment and management of older people in Britain.
Participants People aged ≥ 75 years.
Main outcome measures Mortality (10 123 deaths) determined by follow up through the Office for National Statistics.
Results Month to month variation accounted for 17% of annual all cause mortality, but only 7.8% after adjustment for temperature. The overall winter:non-winter rate ratio was 1.31 (95% confidence interval 1.26 to 1.36). There was little evidence that this ratio varied by geographical region, age, or any of the personal, socioeconomic, or clinical factors examined, with two exceptions: after adjustment for all major covariates the winter:non-winter ratio in women compared with men was 1.11 (1.00 to 1.23), and those with a self reported history of respiratory illness had a winter:non-winter ratio of 1.20 (1.08 to 1.34) times that of people without a history of respiratory illness. There was no evidence that socioeconomic deprivation or self reported financial worries were predictive of winter death.
Conclusion Except for female sex and pre-existing respiratory illness, there was little evidence for vulnerability to winter death associated with factors thought to lead to vulnerability. The lack of socioeconomic gradient suggests that policies aimed at relief of fuel poverty may need to be supplemented by additional measures to tackle the burden of excess winter deaths in elderly people.
doi:10.1136/bmj.38167.589907.55
PMCID: PMC517639  PMID: 15315961
25.  Health impacts of pesticide exposure in a cohort of outdoor workers. 
Environmental Health Perspectives  2003;111(5):724-730.
We compared mortality of 1,999 outdoor staff working as part of an insecticide application program during 1935-1996 with that of 1,984 outdoor workers not occupationally exposed to insecticides, and with the Australian population. Surviving subjects also completed a morbidity questionnaire. Mortality was significantly higher in both exposed and control subjects compared with the Australian population. The major cause was mortality from smoking-related diseases. Mortality was also significantly increased in exposed subjects for a number of conditions that do not appear to be the result of smoking patterns. Compared with the general Australian population, mortality over the total study period was increased for asthma [standardized mortality ratio (SMR) = 3.45; 95% confidence interval (CI), 1.39-7.10] and for diabetes (SMR = 3.57; 95% CI, 1.16-8.32 for subjects working < 5 years). Mortality from pancreatic cancer was more frequent in subjects exposed to 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (SMR = 5.27; 95% CI, 1.09-15.40 for subjects working < 3 years). Compared with the control population, mortality from leukemia was increased in subjects working with more modern chemicals (standardized incidence ratio = 20.90; 95% CI, 1.54-284.41 for myeloid leukemia in the highest exposure group). There was also an increase in self-reported chronic illness and asthma, and lower neuropsychologic functioning scores among surviving exposed subjects when compared with controls. Diabetes was reported more commonly by subjects reporting occupational use of herbicides. These findings lend weight to other studies suggesting an association between adverse health effects and exposure to pesticides.
PMCID: PMC1241482  PMID: 12727601

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