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1.  Babies sleeping with parents: case-control study of factors influencing the risk of the sudden infant death syndrome 
BMJ : British Medical Journal  1999;319(7223):1457-1462.
To investigate the risks of the sudden infant death syndrome and factors that may contribute to unsafe sleeping environments.
Three year, population based case-control study. Parental interviews were conducted for each sudden infant death and for four controls matched for age, locality, and time of sleep.
Five regions in England with a total population of over 17 million people.
325 babies who died and 1300 control infants.
In the multivariate analysis infants who shared their parents' bed and were then put back in their own cot had no increased risk (odds ratio 0.67; 95% confidence interval 0.22 to 2.00). There was an increased risk for infants who shared the bed for the whole sleep or were taken to and found in the parental bed (9.78; 4.02 to 23.83), infants who slept in a separate room from their parents (10.49; 4.26 to 25.81), and infants who shared a sofa (48.99; 5.04 to 475.60). The risk associated with being found in the parental bed was not significant for older infants (>14 weeks) or for infants of parents who did not smoke and became non-significant after adjustment for recent maternal alcohol consumption (>2 units), use of duvets (>4 togs), parental tiredness (infant slept ⩽4 hours for longest sleep in previous 24 hours), and overcrowded housing conditions (>2 people per room of the house).
There are certain circumstances when bed sharing should be avoided, particularly for infants under four months old. Parents sleeping on a sofa with infants should always be avoided. There is no evidence that bed sharing is hazardous for infants of parents who do not smoke.
Key messsagesCosleeping with an infant on a sofa was associated with a particularly high risk of sudden infant death syndromeSharing a room with the parents was associated with a lower riskThere was no increased risk associated with bed sharing when the infant was placed back in his or her cotAmong parents who do not smoke or infants older than 14 weeks there was no association between infants being found in the parental bed and an increased risk of sudden infant death syndromeThe risk linked with bed sharing among younger infants seems to be associated with recent parental consumption of alcohol, overcrowded housing conditions, extreme parental tiredness, and the infant being under a duvet
PMCID: PMC28288  PMID: 10582925
2.  Bed sharing and the sudden infant death syndrome. 
BMJ : British Medical Journal  1995;311(7015):1269-1272.
OBJECTIVE--To determine whether infants who died of the sudden infant death syndrome routinely shared their parents' bed more commonly than control infants. DESIGN--Case-control study. SETTING--Southern California. SUBJECTS--200 white, African-American, Latin American, and Asian infants who died and 200 living controls, matched by birth hospital, date of birth, sex, and race. MAIN OUTCOME MEASURES--Routine bedding (for example, crib, cradle), day and night time sleeping arrangement (for example, alone or sharing a bed); for cases only, sleeping arrangement at death. Differences in bed sharing practices among races. RESULTS--Of the infants who died of the syndrome, 45 (22.4%) were sharing a bed. Daytime bed sharing was more common in African-American (P < 0.001) and Latin American families (P < 0.001) than in white families. The overall adjusted odds ratio for the syndrome and routine bed sharing in the daytime was 1.38 (95% confidence interval 0.59 to 3.22) and for night was 1.21 (0.59 to 2.48). These odds ratios were adjusted for routine sleep position, passive smoking, breast feeding, intercom use, infant birth weight, medical conditions at birth, and maternal age and education. There was no interaction between bed sharing and passive smoking or alcohol use by either parent. CONCLUSIONS--Although there was a significant difference between bed sharing among African-American and Latin American parents compared with white parents, there was no significant relation between routine bed sharing and the sudden infant death syndrome.
PMCID: PMC2551183  PMID: 7496236
3.  Associations between Stroke Mortality and Weekend Working by Stroke Specialist Physicians and Registered Nurses: Prospective Multicentre Cohort Study 
PLoS Medicine  2014;11(8):e1001705.
In a multicenter observational study, Benjamin Bray and colleagues evaluate whether weekend rounds by stroke specialist physicians, or the ratio of registered nurses to beds on weekends, is associated with patient mortality after stroke.
Please see later in the article for the Editors' Summary
Observational studies have reported higher mortality for patients admitted on weekends. It is not known whether this “weekend effect” is modified by clinical staffing levels on weekends. We aimed to test the hypotheses that rounds by stroke specialist physicians 7 d per week and the ratio of registered nurses to beds on weekends are associated with mortality after stroke.
Methods and Findings
We conducted a prospective cohort study of 103 stroke units (SUs) in England. Data of 56,666 patients with stroke admitted between 1 June 2011 and 1 December 2012 were extracted from a national register of stroke care in England. SU characteristics and staffing levels were derived from cross-sectional survey. Cox proportional hazards models were used to estimate hazard ratios (HRs) of 30-d post-admission mortality, adjusting for case mix, organisational, staffing, and care quality variables. After adjusting for confounders, there was no significant difference in mortality risk for patients admitted to a stroke service with stroke specialist physician rounds fewer than 7 d per week (adjusted HR [aHR] 1.04, 95% CI 0.91–1.18) compared to patients admitted to a service with rounds 7 d per week. There was a dose–response relationship between weekend nurse/bed ratios and mortality risk, with the highest risk of death observed in stroke services with the lowest nurse/bed ratios. In multivariable analysis, patients admitted on a weekend to a SU with 1.5 nurses/ten beds had an estimated adjusted 30-d mortality risk of 15.2% (aHR 1.18, 95% CI 1.07–1.29) compared to 11.2% for patients admitted to a unit with 3.0 nurses/ten beds (aHR 0.85, 95% CI 0.77–0.93), equivalent to one excess death per 25 admissions. The main limitation is the risk of confounding from unmeasured characteristics of stroke services.
Mortality outcomes after stroke are associated with the intensity of weekend staffing by registered nurses but not 7-d/wk ward rounds by stroke specialist physicians. The findings have implications for quality improvement and resource allocation in stroke care.
Please see later in the article for the Editors' Summary
Editors' Summary
In a perfect world, a patient admitted to hospital on a weekend or during the night should have as good an outcome as a patient admitted during regular working hours. But several observational studies (investigations that record patient outcomes without intervening in any way; clinical trials, by contrast, test potential healthcare interventions by comparing the outcomes of patients who are deliberately given different treatments) have reported that admission on weekends is associated with a higher mortality (death) rate than admission on weekdays. This “weekend effect” has led to calls for increased medical and nursing staff to be available in hospitals during the weekend and overnight to ensure that the healthcare provided at these times is of equal quality to that provided during regular working hours. In the UK, for example, “seven-day working” has been identified as a policy and service improvement priority for the National Health Service.
Why Was This Study Done?
Few studies have actually tested the relationship between patient outcomes and weekend physician or nurse staffing levels. It could be that patients who are admitted to hospital on the weekend have poor outcomes because they are generally more ill than those admitted on weekdays. Before any health system introduces potentially expensive increases in weekend staffing levels, better evidence that this intervention will improve patient outcomes is needed. In this prospective cohort study (a study that compares the outcomes of groups of people with different baseline characteristics), the researchers ask whether mortality after stroke is associated with weekend working by stroke specialist physicians and registered nurses. Stroke occurs when the brain's blood supply is interrupted by a blood vessel in the brain bursting (hemorrhagic stroke) or being blocked by a blood clot (ischemic stroke). Swift treatment can limit the damage to the brain caused by stroke, but of the 15 million people who have a stroke every year, about 6 million die within a few hours and another 5 million are left disabled.
What Did the Researchers Do and Find?
The researchers extracted clinical data on 56,666 patients who were admitted to stroke units in England over an 18-month period from a national stroke register. They obtained information on the characteristics and staffing levels of the stroke units from a biennial survey of hospitals admitting patients with stroke, and information on deaths among patients with stroke from the national register of deaths. A quarter of the patients were admitted on a weekend, almost half the stroke units provided stroke specialist physician rounds seven days per week, and the remainder provided rounds five days per week. After adjustment for factors that might have affected outcomes (“confounders”) such as stroke severity and the level of acute stroke care available in each stroke unit, there was no significant difference in mortality risk between patients admitted to a stroke unit with rounds seven days/week and patients admitted to a unit with rounds fewer than seven days/week. However, patients admitted on a weekend to a stroke unit with 1.5 nurses/ten beds had a 30-day mortality risk of 15.2%, whereas patients admitted to a unit with 3.0 nurses/ten beds had a mortality risk of 11.2%, a mortality risk difference equivalent to one excess death per 25 admissions.
What Do These Findings Mean?
These findings show that the provision of stroke specialist physician rounds seven days/week in stroke units in England did not influence the (weak) association between weekend admission for stroke and death recorded in this study, but mortality outcomes after stroke were associated with the intensity of weekend staffing by registered nurses. The accuracy of these findings may be affected by the measure used to judge the level of acute care available in each stroke unit and by residual confounding. For example, patients admitted to units with lower nursing levels may have shared other unknown characteristics that increased their risk of dying after stroke. Moreover, this study considered the impact of staffing levels on mortality only and did not consider other relevant outcomes such as long-term disability. Despite these limitations, these findings support the provision of higher weekend ratios of registered nurses to beds in stroke units, but given the high costs of increasing weekend staffing levels, it is important that controlled trials of different models of physician and nursing staffing are undertaken as soon as possible.
Additional Information
Please access these websites via the online version of this summary at
This study is further discussed in a PLOS Medicine Perspective by Meeta Kerlin
Information about plans to introduce seven-day working into the National Health Service in England is available; the 2013 publication “NHS Services—Open Seven Days a Week: Every Day Counts” provides examples of how hospitals across England are working together to provide routine healthcare services seven days a week; a “Behind the Headlines” article on the UK National Health Service Choices website describes a recent observational study that investigated the association between admission to hospital on the weekend and death, and newspaper coverage of the study's results; the Choices website also provides information about stroke for patients and their families, including personal stories
A US nurses' site includes information on the association of nurse staffing with patient safety
The US National Institute of Neurological Disorders and Stroke provides information about all aspects of stroke (in English and Spanish); its Know Stroke site provides educational materials about stroke prevention, treatment, and rehabilitation, including personal stories (in English and Spanish); the US National Institute of Health SeniorHealth website has additional information about stroke
The Internet Stroke Center provides detailed information about stroke for patients, families, and health professionals (in English and Spanish)
PMCID: PMC4138029  PMID: 25137386
4.  Environment of infants during sleep and risk of the sudden infant death syndrome: results of 1993-5 case-control study for confidential inquiry into stillbirths and deaths in infancy. Confidential Enquiry into Stillbirths and Deaths Regional Coordinators and Researchers. 
BMJ : British Medical Journal  1996;313(7051):191-195.
OBJECTIVE--To investigate the role of sleeping arrangements as risk factors for the sudden infant death syndrome after a national risk reduction campaign. DESIGN--Two year population based case-control study. Parental interviews were conducted for each infant who died and for four controls matched for age and date of interview. SETTING--Three regions in England with a total population of 17 million people. SUBJECTS--195 babies who died and 780 matched controls. RESULTS--Prone and side sleeping positions both carried increased risks of death compared with supine when adjusted for maternal age, parity, gestation, birth weight, exposure to smoke, and other relevant factors in the sleeping environment (multivariate odds ratio = 9.00 (95% confidence interval 2.84 to 28.47) and 1.84 (1.02 to 3.31), respectively). The higher incidence of side rather than prone sleeping led to a higher population attributable risk (side 18.4%, prone 14.2%). More of the infants who died were found with bed covers over their heads (21.58; 6.21 to 74.99). The use of a dummy had an apparent protective effect (0.38; 0.21 to 0.70). Bed sharing for the whole night was a significant risk factor for infants whose mothers smoked (9.25; 2.31 to 34.02). No protective effect of breast feeding could be identified on multivariate analysis. CONCLUSIONS--This study confirms the importance of certain risk factors for the sudden infant death syndrome and identifies others-for example, covers over the head, side sleeping position-which may be amenable to change by educating and informing parents and health care professionals.
PMCID: PMC2351639  PMID: 8696193
5.  Case-control study of sudden infant death syndrome in Scotland, 1992-5. 
BMJ : British Medical Journal  1997;314(7093):1516-1520.
OBJECTIVE: To investigate the relation between routine infant care practices and the sudden infant death syndrome in Scotland. METHODS: National study of 201 infants dying of the sudden infant death syndrome (cases) and 276 controls by means of home interviews comparing methods of infant care and socioeconomic factors. RESULTS: Sleeping prone (odds ratio 6.96 (95% confidence interval 1.51 to 31.97) and drug treatment in the previous week (odds ratio 2.33 (1.10 to 4.94)) were more common in the cases than controls on multivariate analysis. Smoking was confirmed as a significant risk factor (odds ratio for mother and father both smoking 5.19 (2.26 to 11.91)). The risk increased with the number of parents smoking (P < 0.0001), with the number of cigarettes smoked by mother or father (P = 0.0001), and with bed sharing (P < 0.005). A new finding was an increased risk of dying of the syndrome for infants who slept at night on a mattress previously used by another infant or adult (odds ratio 2.51 (1.39 to 4.52)). However, this increased risk was not established for mattresses totally covered by polyvinyl chloride. CONCLUSIONS: Sleeping prone and parental smoking are confirmed as modifiable risk factors for the sudden infant death syndrome. Sleeping on an old mattress may be important but needs confirmation before recommendations can be made.
PMCID: PMC2126747  PMID: 9169398
6.  Case-control study of sudden infant death syndrome in Lithuania, 1997–2000 
BMC Pediatrics  2005;5:41.
To identify risk factors for sudden infant death syndrome relevant in Lithuania.
A nationwide case-control study surveying parents of 35 infants who died from sudden infant death syndrome during the period of 1997–2000 and parents of 145 control infants matched with SIDS infants for date of birth and for region of birth was carried out.
Deaths incidence was greater in the warm period (60%) vs. cold period (40%). Prone and side sleeping positions both carried no increased risk of sudden infant death syndrome compared with supine because of a rare prone sleeping (4.1% of controls vs. 0% of dead infants) and more prevalent side than supine sleeping (84.8% of controls vs. 94.3% of dead infants) in the controls as well as the cases. Bed sharing for the whole night as a risk factor for sudden infant death syndrome has not been confirmed, either, as bed sharing was common only for the controls (13.8% of controls vs. 0% of dead infants). Routine sleeping environment factors such as heavy wrapping (≥4 togs) of an infant (odds ratio 8.49; 95% confidence interval 2.38 to 30.32), sleeping in a bassinet (4.22; 1.16 to 15.38) and maternal factors such as maternal education ≤12 years (4.48; 1.34 to 14.94), unplanned pregnancy (5.22; 1.49 to 18.18) and ≥2 previous live births (3.90; 1.00 to 15.10) were significantly associated with sudden infant death syndrome on multivariate analysis.
The results of this first population-based case-control study have shed some light on the epidemiology of the syndrome in Lithuania. Although the mortality of sudden infant death syndrome in Lithuania is not high, it might be lowered moreover by public informing about sudden infant death syndrome and related risk factors. Special attention must be paid to mothers with low education on potentially modifiable risk factors such as routine heavy wrapping of an infant during sleep, routine sleeping in a bassinet and unplanned pregnancy.
PMCID: PMC1308821  PMID: 16283946
7.  Sudden infant death syndrome: bed sharing with mothers who smoke 
Archives of Disease in Childhood  2003;88(2):112-113.
Aim: To examine the sleeping arrangements of sudden infant death syndrome (SIDS) cases on the Wirral. In particular to determine the prevalence of bed sharing with mothers who smoke, a known risk factor for SIDS.
Methods: Retrospective study of postmortem determined cases of SIDS from 1995 to 2000 on the Wirral peninsula (population 350 000, 3500 annual births). Ambulance crew reports, case notes, health visitor reports, postmortem reports, and case discussion records were studied for each case.
Results: There were 25 cases of SIDS in the postneonatal age group over the six year period. In nine cases the baby was bed sharing with the mother, of whom seven were smokers. Five of these mothers reported using alcohol or illicit drugs on the night of their infant's death. In two further cases the baby slept on a sofa with a parent.
Conclusions: Bed sharing and smoking remain important risk factors for SIDS. Mothers should be advised ante- and postnatally of this combination of risk factors. Such advice should also include a recommendation not to sleep with their baby if under the influence of alcohol or illicit drugs, and never to sleep on a sofa with their baby. All "Child Health Record" books given to parents on the Wirral now include this advice. "Reduce the Risk" advice leaflets given to parents pre- and postnatally also now carry the recommendation, and health visitors and midwives have been educated with respect to these additions.
PMCID: PMC1719436  PMID: 12538308
8.  Sudden infant death syndrome and sleeping position in pre‐term and low birth weight infants: an opportunity for targeted intervention 
Archives of Disease in Childhood  2005;91(2):101-106.
To determine the combined effects of sudden infant death syndrome (SIDS) risk factors in the sleeping environment for infants who were “small at birth” (pre‐term (<37 weeks), low birth weight (<2500 g), or both).
A three year population based, case‐control study in five former health regions in England (population 17.7 million) with 325 cases and 1300 controls. Parental interviews were carried out after each death and reference sleep of age matched controls.
Of the SIDS infants, 26% were “small at birth” compared to 8% of the controls. The most common sleeping position was supine, for both controls (69%) and those SIDS infants (48%) born at term or ⩾2500 g, but for “small at birth” SIDS infants the commonest sleeping position was side (48%). The combined effect of the risk associated with being “small at birth” and factors in the infant sleeping environment remained multiplicative despite controlling for possible confounding in the multivariate model. This effect was more than multiplicative for those infants placed to sleep on their side or who shared the bed with parents who habitually smoked, while for those “small at birth” SIDS who slept in a room separate from the parents, the large combined effect showed evidence of a significant interaction. No excess risk was identified from bed sharing with non‐smoking parents for infants born at term or birth weight ⩾2500 g.
The combined effects of SIDS risk factors in the sleeping environment and being pre‐term or low birth weight generate high risks for these infants. Their longer postnatal stay allows an opportunity to target parents and staff with risk reduction messages.
PMCID: PMC2082697  PMID: 15914498
SIDS; pre‐term; low birth weight; infant sleeping position; co‐sleeping
9.  Bed-sharing and the infant's thermal environment in the home setting 
Archives of Disease in Childhood  2004;89(12):1111-1116.
Aims: To study bed-sharing and cot-sleeping infants in the natural setting of their own home in order to identify differences in the thermal characteristics of the two sleep situations and their potential hazards.
Methods: Forty routine bed-sharing infants and 40 routine cot-sleeping infants aged 5–27 weeks were individually matched between groups for age and season. Overnight video and physiological data of bed-share infants and cot-sleeping infants were recorded in the infants' own homes including rectal, shin, and ambient temperature.
Results: The mean rectal temperature two hours after sleep onset for bed-share infants was 36.79°C and for cot-sleeping infants, 36.75°C (difference 0.05°C, 95% CI –0.03 to 0.14). The rate of change thereafter was higher in the bed-share group than in the cot group (0.04°C v 0.03°C/h, difference 0.01, 0.00 to 0.02). Bed-share infants had a higher shin temperature at two hours (35.43 v 34.60°C, difference 0.83, 0.18 to 1.49) and a higher rate of change (0.04 v –0.10°C/h, difference 0.13, 0.08 to 0.19). Bed-sharing infants had more bedding. Face covering events were more common and bed-share infants woke and fed more frequently than cot infants (mean wake times/night: 4.6 v 2.5).
Conclusions: Bed-share infants experience warmer thermal conditions than those of cot-sleeping infants, but are able to maintain adequate thermoregulation to maintain a normal core temperature.
PMCID: PMC1719737  PMID: 15557043
10.  Infant Bed-Sharing Practices and Associated Risk Factors Among Births and Infant Deaths in Alaska 
Public Health Reports  2009;124(4):527-534.
The Alaska Division of Public Health has stated that infants may safely share a bed for sleeping if this occurs with a nonsmoking, unimpaired caregiver on a standard, adult, non-water mattress. Because this policy is contrary to recent national recommendations that discourage any bed sharing, we examined 13 years of Alaskan infant deaths that occurred while bed sharing to assess the contribution of known risk factors.
We examined vital records, medical records, autopsy reports, and first responder reports for 93% of Alaskan infant deaths that occurred between 1992 and 2004. We examined deaths while bed sharing for risk factors including sleeping with a non-caregiver, prone position, maternal tobacco use, impairment of a bed-sharing partner, and an unsafe sleep surface. We used Pregnancy Risk Assessment Monitoring System data to describe bed-sharing practices among all live births in Alaska during 1996–2003.
Thirteen percent (n=126) of deaths occurred while bed sharing; 99% of these had at least one associated risk factor, including maternal tobacco use (75%) and sleeping with an impaired person (43%). Frequent bed sharing was reported for 38% of Alaskan infants. Among these, 60% of mothers reported no risk factors; the remaining 40% reported substance use, smoking, high levels of alcohol use, or most often placing their infant prone for sleeping.
Almost all bed-sharing deaths occurred in association with other risk factors despite the finding that most women reporting frequent bed sharing had no risk factors; this suggests that bed sharing alone does not increase the risk of infant death.
PMCID: PMC2693166  PMID: 19618789
11.  Trends and Factors Associated with Bed-Sharing: The National Infant Sleep Position Study (NISP) 1993–2010 
JAMA pediatrics  2013;167(11):1032-1037.
Determine trends and factors associated with bed-sharing.
National Infant Sleep Position Study: Annual telephone surveys.
48 contiguous United States.
Nighttime caregivers of infants born within the last 7 months between 1993 and 2010. Approximately 1000 interviews annually.
Main Outcome Measure
Infant usually bed-sharing.
Of 18,986 participants, 11% reported usually bed-sharing. Bed-sharing increased between 1993 (6.0%) and 2010 (13.5%). While there was an increase for Whites from 1993 to 2000 (p<0.001), there was no significant increase from 2001 to 2010 (p=0.48). Blacks and Hispanics showed increase in bed-sharing throughout the period 1993 to 2010, with no difference between the two time periods (p=0.63 and 0.77, respectively). After accounting for study year, factors associated with increase in usually bed-sharing included: compared to college or more, maternal education less than high school (AOR = 1.4; 95% CI, 1.1–1.8), compared to White race, maternal race or ethnicity Black (AOR = 3.5; 95% CI, 3.0–4.1), Hispanic (AOR = 1.3; 95% CI, 1.1–1.6) and Other (AOR 2.5; 95% CI, 2.0–3.0), compared to household income ≥$50,000, less than $20 000 (AOR = 1.7; 95% CI, 1.4–2.0) and $20–$50,000 (AOR=1.3; 95%CI 1.1–1.5), compared with living in the Midwest, living in the West (AOR=1.6; 95%CI 1.4–1.9) or South (AOR=1.5; 95% CI=1.3–1.7), compared with infant age ≥16 weeks, less than 8 weeks (AOR = 1.5; 95%CI 1.2–1.7 and 8–15 weeks (AOR-1.3; 95% CI=1.2–1.5) and being born prematurely (AOR = 1.4; 95% CI, 1.2–1.6).
Thirty-six percent of the participants reported talking to a doctor about bed-sharing. Compared with those who did not talk to a doctor, those who reported their doctors had a negative attitude were less likely to bed-share (AOR 0.66 (95% 0.53, 0.82), whereas a neutral attitude was associated with increased bed-sharing. (AOR 1.4; 95%CI 1.1–1.8).
Our findings of the continual increase in bed-sharing throughout the period 1993–2010 among Black and Hispanic infants suggests that the current recommendation about bed-sharing is not universally followed.
PMCID: PMC3903787  PMID: 24080961
Bed-sharing; SIDS; racial disparity; infant mortality
12.  Bed sharing, smoking, and alcohol in the sudden infant death syndrome. New Zealand Cot Death Study Group. 
BMJ : British Medical Journal  1993;307(6915):1312-1318.
OBJECTIVES--To investigate why sharing the bed with an infant is a not consistent risk factor for the sudden infant death syndrome in ethnic subgroups in New Zealand and to see if the risk of sudden infant death associated with this practice is related to other factors, particularly maternal smoking and alcohol consumption. DESIGN--Nationwide case-control study. SETTING--Region of New Zealand with 78% of all births during 1987-90. SUBJECTS--Home interviews were completed with parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region. RESULTS--Maternal smoking interacted with infant bed sharing on the risk of sudden infant death. Compared with infants not exposed to either risk factor, the relative risk for infants of mothers who smoked was 3.94 (95% confidence interval 2.47 to 6.27) for bed sharing in the last two weeks and 4.55 (2.63 to 7.88) for bed sharing in the last sleep, after other confounders were controlled for. The results for infants of non-smoking mothers were inconsistent with the relative risk being significantly increased for usual bed sharing in the last two weeks (1.73; 1.11 to 2.70) but not for bed sharing in the last sleep (0.98; 0.44 to 2.18). Neither maternal alcohol consumption nor the thermal resistance of the infant's clothing and bedding interacted with bed sharing to increase the risk of sudden infant death, and alcohol was not a risk factor by itself. CONCLUSION--Infant bed sharing is associated with a significantly raised risk of the sudden infant death syndrome, particularly among infants of mothers who smoke. The interaction between maternal smoking and bed sharing suggests that a mechanism involving passive smoking, rather than the previously proposed mechanisms of overlaying and hyperthermia, increases the risk of sudden infant death from bed sharing.
PMCID: PMC1679405  PMID: 8257885
13.  Nighttime Parenting Strategies and Sleep-Related Risks to Infants 
A large social science and public health literature addresses infant sleep safety, with implications for infant mortality in the context of accidental deaths and Sudden Infant Death Syndrome (SIDS). As part of risk reduction campaigns in the USA, parents are encouraged to place infants supine and to alter infant bedding and elements of the sleep environment, and are discouraged from allowing infants to sleep unsupervised, from bed-sharing either at all or under specific circumstances, or from sofa-sharing. These recommendations are based on findings from large-scale epidemiological studies that generate odds ratios or relative risk statistics for various practices; however, detailed behavioural data on nighttime parenting and infant sleep environments are limited. To address this issue, this paper presents and discusses the implications of four case studies based on overnight observations conducted with first-time mothers and their four-month old infants. These case studies were collected at the Mother-Baby Behavioral Sleep Lab at the University of Notre Dame USA between September 2002 and June 2004.Each case study provides a detailed description based on video analysis of sleep-related risks observed while mother-infant dyads spent the night in a sleep lab. The case studies provide examples of mothers engaged in the strategic management of nighttime parenting for whom sleep-related risks to infants arose as a result of these strategies. Although risk reduction guidelines focus on eliminating potentially risky infant sleep practices as if the probability of death from each were equal, the majority of instances in which these occur are unlikely to result in infant mortality. Therefore, we hypothesise that mothers assess potential costs and benefits within margins of risk which are not acknowledged by risk-reduction campaigns. Exploring why mothers might choose to manage sleep and nighttime parenting in ways that appear to increase potential risks to infants may help illuminate how risks occur for individual infants.
PMCID: PMC3505270  PMID: 22818487
infant sleep; sleep-related risks; Sudden Infant Death Syndrome (SIDS); nighttime parenting; USA
14.  Sudden Unexpected Death in Infancy: place and time of death 
The Ulster Medical Journal  2006;75(1):65-71.
In recent years, many babies who die of Sudden Unexpected Death in Infancy (SUDI) in Northern Ireland are found dead in bed – i.e. co-sleeping – with an adult. In order to assess its frequency autopsy reports between April 1996 and August 2001 were reviewed and linked to temporal factors. The day and month of death, and the place where the baby was found were compared to a reference population of infant deaths between one week of age and the second birthday.
Although the rate of SUDI was lower than the UK average, 43 cases of SUDI were identified, and two additional deaths with virtually identical autopsy findings that were attributed to asphyxia caused by suffocation due to overlaying. Thirty-two of the 45 (71%) were less than four months of age. In 30 of the 45 cases (67%) the history stated that the baby was bed sharing with others; 19 died sleeping in an adult bed, and 11 on a sofa or armchair. In 16 of the 30 (53%) there were at least two other people sharing the sleeping surface, and in one case, three. SUDI was twice as frequent at weekends (found dead Saturday – Monday mornings) compared to weekdays (p<0.02), and significantly more common compared to reference deaths (p<0.002). Co-sleeping deaths were also more frequent at weekends. Almost half of all SUDI (49%) occurred in the summer months – more than twice the frequency of reference deaths.
While sharing a place of sleep per se may not increase the risk of death, our findings may be linked to factors such as habitual smoking, consumption of alcohol or illicit drugs as reported in case-control studies. In advising parents on safer childcare practices, health professionals must be knowledgeable of current research and when, for example, giving advice on co-sleeping this needs to be person-specific cognisant of the risks within a household. New and better means of targeting such information needs to be researched if those with higher risk life-styles are to be positively influenced.
PMCID: PMC1891806  PMID: 16457407
15.  Rapid Scaling Up of Insecticide-Treated Bed Net Coverage in Africa and Its Relationship with Development Assistance for Health: A Systematic Synthesis of Supply, Distribution, and Household Survey Data 
PLoS Medicine  2010;7(8):e1000328.
Stephen Lim and colleagues use several sources of data to estimate the changes in distribution of insecticide-treated bed nets across Africa between 2000 and 2008, and to analyze the link between development assistance and net coverage.
Development assistance for health (DAH) targeted at malaria has risen exponentially over the last 10 years, with a large fraction of these resources directed toward the distribution of insecticide-treated bed nets (ITNs). Identifying countries that have been successful in scaling up ITN coverage and understanding the role of DAH is critical for making progress in countries where coverage remains low. Sparse and inconsistent sources of data have prevented robust estimates of the coverage of ITNs over time.
Methods and Principal Findings
We combined data from manufacturer reports of ITN deliveries to countries, National Malaria Control Program (NMCP) reports of ITNs distributed to health facilities and operational partners, and household survey data using Bayesian inference on a deterministic compartmental model of ITN distribution. For 44 countries in Africa, we calculated (1) ITN ownership coverage, defined as the proportion of households that own at least one ITN, and (2) ITN use in children under 5 coverage, defined as the proportion of children under the age of 5 years who slept under an ITN. Using regression, we examined the relationship between cumulative DAH targeted at malaria between 2000 and 2008 and the change in national-level ITN coverage over the same time period. In 1999, assuming that all ITNs are owned and used in populations at risk of malaria, mean coverage of ITN ownership and use in children under 5 among populations at risk of malaria were 2.2% and 1.5%, respectively, and were uniformly low across all 44 countries. In 2003, coverage of ITN ownership and use in children under 5 was 5.1% (95% uncertainty interval 4.6% to 5.7%) and 3.7% (2.9% to 4.9%); in 2006 it was 17.5% (16.4% to 18.8%) and 12.9% (10.8% to 15.4%); and by 2008 it was 32.8% (31.4% to 34.4%) and 26.6% (22.3% to 30.9%), respectively. In 2008, four countries had ITN ownership coverage of 80% or greater; six countries were between 60% and 80%; nine countries were between 40% and 60%; 12 countries were between 20% and 40%; and 13 countries had coverage below 20%. Excluding four outlier countries, each US$1 per capita in malaria DAH was associated with a significant increase in ITN household coverage and ITN use in children under 5 coverage of 5.3 percentage points (3.7 to 6.9) and 4.6 percentage points (2.5 to 6.7), respectively.
Rapid increases in ITN coverage have occurred in some of the poorest countries, but coverage remains low in large populations at risk. DAH targeted at malaria can lead to improvements in ITN coverage; inadequate financing may be a reason for lack of progress in some countries.
Please see later in the article for the Editors' Summary
Editors' Summary
Malaria is a major global public-health problem. Nearly half of the world's population is at risk of this parasitic disease, which kills about one million people (mainly children living in sub-Saharan Africa) every year. Malaria is transmitted to people through the bites of infected night-flying mosquitoes. Soon after entering the human body, the parasite begins to replicate in red blood cells, bursting out every 2–3 days and infecting more red blood cells. The parasite's presence in the bloodstream causes malaria's characteristic fever and can cause fatal organ damage. Malaria can be prevented by controlling the mosquitoes that spread the parasite and by sleeping under insecticide-treated bed nets (ITNs) to avoid mosquito bites. In trials, ITN use reduced deaths in young children by about 20%. Consequently, the widespread provision of ITNs is a mainstay of the World Health Organization's efforts to control malaria and in 2005 the World Assembly agreed to a target of providing ITNs for 80% of the people at risk of malaria by 2010.
Why Was This Study Done?
Development assistance for health (DAH) targeted at malaria has increased considerably over the past decade. Much of this resource has been directed toward increasing ITN coverage, but has it been used effectively? To answer this question and to track progress toward universal ITN provision, reliable estimates of ITN coverage are critical. Most attempts to quantify ITN coverage have relied on single sources of data such as manufacturers' records of ITNs supplied to individual countries, National Malaria Control Program reports on ITN distribution, or household surveys of ITN use. Because each of these data sources has weaknesses, robust estimates of ITN coverage over time cannot be calculated from a single data source. In this study, the researchers combine data from these three sources to calculate ITN ownership coverage (the proportion of households owning at least one ITN) and ITN use in children under 5 coverage (the proportion of children under the age of 5 years sleeping under an ITN) for 44 African countries between 1999 and 2008. They also investigate the relationship between changes in ITN coverage and the cumulative DAH targeted for malaria for each country over this period.
What Did the Researchers Do and Find?
The researchers combined the three sources of data by applying a statistical method called Bayesian inference to a “deterministic compartmental model” of ITN distribution, a flow chart that represents ITN movement into and within countries. In 1999, the researchers estimate, ITN ownership and ITN use by young children were uniformly low across the 44 countries. On average, only 2.2% of households owned ITNs and only 1.5% of young children slept under bed nets. By 2008, 32.8% of households owned ITNs and 26.6% of young children slept under ITNs but there were now large differences in ITN coverage between countries. In four countries, 80% or more of households owned an ITN but in 13 countries (including Nigeria), ITN ownership was below 20%. Finally, the researchers used a statistical technique called regression to reveal that the estimated increase in national ITN coverage between 2000 and 2008 was strongly related to the cumulative national DAH targeted for malaria (calculated by identifying all the grants and loans provided for malaria control) over the same period.
What Do These Findings Mean?
The accuracy of these findings depends on the assumptions included in the model of ITN distribution and the quality of the data fed into it. Nevertheless, this systematic analysis provides new insights into the progress of ITN provision in Africa and a robust way to monitor future ITN coverage. Its findings show that several countries, even some very poor countries, have managed to scale up their ITN coverage from near zero to above 60%. However, because countries such as Nigeria that have large populations at risk of malaria continue to have low ITN coverage, Africa as a whole falls far short of the target of 80% ITN coverage by 2010. Finally, the clear relationship between the expansion of DAH targeted at malaria and increased ITN coverage suggests that inadequate funding may be responsible for the lack of progress in some countries and indicates that continued external financial assistance will be required to maintain the improvements in ITN coverage that have already been achieved.
Additional Information
Please access these Web sites via the online version of this summary at
Further information is available on the Institute for Health Metrics and Evaluation at the University of Washington
Information is available from the World Health Organization on malaria (in several languages); the 2009 World Malaria Report provides details of the current global malaria situation
The US Centers for Disease Control and Prevention provide information on malaria and on insecticide-treated bed nets (in English and Spanish)
Information is available from the Roll Back Malaria Partnership on its approach to the global control of malaria including fact sheets on malaria in Africa and on insecticide-treated bed nets (in English, French and Portuguese)
MedlinePlus provides links to additional information on malaria (in English and Spanish)
PMCID: PMC2923089  PMID: 20808957
16.  Hazardous cosleeping environments and risk factors amenable to change: case-control study of SIDS in south west England 
Objectives To investigate the factors associated with sudden infant death syndrome (SIDS) from birth to age 2 years, whether recent advice has been followed, whether any new risk factors have emerged, and the specific circumstances in which SIDS occurs while cosleeping (infant sharing the same bed or sofa with an adult or child).
Design Four year population based case-control study. Parents were interviewed shortly after the death or after the reference sleep (within 24 hours) of the two control groups.
Setting South west region of England (population 4.9 million, 184 800 births).
Participants 80 SIDS infants and two control groups weighted for age and time of reference sleep: 87 randomly selected controls and 82 controls at high risk of SIDS (young, socially deprived, multiparous mothers who smoked).
Results The median age at death (66 days) was more than three weeks less than in a study in the same region a decade earlier. Of the SIDS infants, 54% died while cosleeping compared with 20% among both control groups. Much of this excess may be explained by a significant multivariable interaction between cosleeping and recent parental use of alcohol or drugs (31% v 3% random controls) and the increased proportion of SIDS infants who had coslept on a sofa (17% v 1%). One fifth of SIDS infants used a pillow for the last sleep (21% v 3%) and one quarter were swaddled (24% v 6%). More mothers of SIDS infants than random control infants smoked during pregnancy (60% v 14%), whereas one quarter of the SIDS infants were preterm (26% v 5%) or were in fair or poor health for the last sleep (28% v 6%). All of these differences were significant in the multivariable analysis regardless of which control group was used for comparison. The significance of covering the infant’s head, postnatal exposure to tobacco smoke, dummy use, and sleeping in the side position has diminished although a significant proportion of SIDS infants were still found prone (29% v 10%).
Conclusions Many of the SIDS infants had coslept in a hazardous environment. The major influences on risk, regardless of markers for socioeconomic deprivation, are amenable to change and specific advice needs to be given, particularly on use of alcohol or drugs before cosleeping and cosleeping on a sofa.
PMCID: PMC2762037  PMID: 19826174
17.  The Physical and Social Environment of Sleep in Socioeconomically Disadvantaged Postpartum Women 
To describe the physical and social environment of sleep self-management in postpartum socioeconomically disadvantaged women.
Descriptive, exploratory design.
Participants were recruited in the hospital after giving birth. Data were collected in participant homes after discharge.
Postpartum women on Medicaid with normal healthy infants.
Participants completed a survey about features within their physical and social sleep environment at 2 weeks postpartum. Participants then completed three days and nights of sleep diaries at both 4 and 8 weeks postpartum to document perceived awakenings, select sleep hygiene practices, bed sharing, and reasons for sleep disruption.
The sleep environments of participants were dynamic from night to night. Bed sharing was common with nearly half of participants sharing with a partner, approximately 25 percent with the infant, and 20 percent with older children. Fifty-two percent of participants slept with the television on part (31%) or all (69%) of the night. Eight-five percent of participants drank caffeine and 24 percent smoked.
These results inform theory-driven postpartum sleep interventions. Modifications to the physical and social sleep environment that attend specifically to how sleep hygiene and environmental factors are manifested in the postpartum period have the potential to improve sleep for socioeconomically disadvantaged women. Future research is needed to articulate which changes can be effectively self-managed by mothers through nursing interventions.
PMCID: PMC3546265  PMID: 23181913
sleep hygiene; sleep environment; postpartum; bed sharing; socioeconomic disadvantage
18.  Maternal Assessment of Physician Qualification to Give Advice on AAP-Recommended Infant Sleep Practices Related to SIDS 
Academic pediatrics  2010;10(6):383-388.
The American Academy of Pediatrics (AAP) strongly recommends the supine-only sleep position for infants and issued 2 more sudden infant death syndrome (SIDS) reduction recommendations: avoid bed sharing and use pacifiers during sleep. In this study, we investigated the following: 1) if mothers from at risk populations rate physicians as qualified to give advice about sleep practices and 2) if these ratings were associated with reports of recommended practice.
A cross-sectional survey of mothers (N = 2355) of infants aged <8 months was conducted at Women, Infants, and Children (WIC) Program centers in 6 cities from 2006 to 2008. The predictor measures were maternal rating of physician qualification to give advice about 3 recommended sleep practices and reported nature of physician advice. The dependent measures were maternal report of usage of recommended behavior: 1) “infant usually placed supine for sleep,” 2) “infant usually does not share a bed with an adult during sleep,” and 3) “infant usually uses a pacifier during sleep.”
Physician qualification ratings varied by topic: sleep position (80%), bed sharing (69%), and pacifier use (60%). High ratings of physician qualification were associated with maternal reports of recommended behavior: supine sleep (adjusted odds ratio [AOR] 2.1, 95% confidence interval [CI], 1.6–2.6); usually no bed sharing (AOR 1.5, 95% CI, 1.2–1.9), and usually use a pacifier during sleep (AOR 1.2, 95% CI, 1.0–1.5).
High maternal ratings of physician qualification to give advice on 2 of the 3 recommended sleep practices targeted to reduce the risk of SIDS were significantly associated with maternal report of using these behaviors. Lower ratings of physician qualification to give advice about these sleep practices may undermine physician effectiveness in promoting the recommended behavior.
PMCID: PMC3209617  PMID: 21075318
Back to Sleep campaign; infant mortality disparities; sleep position; sudden infant death syndrome
19.  Bed-sharing and risk of hospitalisation due to pneumonia and diarrhoea in infancy: the 2004 Pelotas Birth Cohort 
To investigate the association between bed-sharing with the mother at 3 months of age and incidence of hospitalisation due to pneumonia and diarrhoea between 3 and 12 months.
The 2004 Pelotas Birth Cohort included all live births to mothers living in Pelotas, Brazil, in 2004. Information on bed-sharing was obtained at the 3-month follow-up visit, and on hospitalisations at the 12-month visit, both based on mothers’ reports. Only singleton infants with complete information on hospitalisation were analysed.
3906 infants were included. The bed-sharing prevalence at 3 months was 46.4% (95% CI 44.9 to 48.0%). The incidence of pneumonia admissions between 3 and 12 months was 3.6% (95% CI 3.3 to 4.2%) and diarrhoea, 0.9% (95% CI 0.6 to 1.2%). In crude analyses, bed-sharing with the mother was associated with higher incidence of hospitalisation due to both pneumonia and diarrhoea. There was interaction between bed-sharing and duration of breastfeeding regarding the chance of admission due to pneumonia. Among infants breastfed for 3 months or less, the chance of hospitalisation due to pneumonia among bed-sharers was almost twice as high as among non-bed-sharers (adjusted OR 1.96; 95% CI 1.08 to 3.55). There was no association between bed-sharing and hospitalisation due to pneumonia among infants breastfed for longer than 3 months in crude or adjusted analyses. The association between bed-sharing and admissions due to diarrhoea lost statistical significance after allowing for confounders.
The effect of bed-sharing in infancy on the risk of hospitalisation due to pneumonia depends on breastfeeding, such that weaned children present higher risk.
PMCID: PMC3585489  PMID: 23100381
Breast Feeding; Child Health; Sleep; Epidemiology; Public Health
20.  SIDS 
Clinical Evidence  2009;2009:0315.
By definition, the cause of sudden infant death syndrome (SIDS) is not known. Observational studies have found an association between SIDS and several risk factors, including prone sleeping position, prenatal or postnatal exposure to tobacco smoke, soft sleeping surfaces, hyperthermia/overwrapping, bed sharing (particularly with mothers who smoke), lack of breastfeeding, and lack of soother use. The risk of SIDS is increased in families in which there has been a prior sudden infant death.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of interventions to reduce the risk of SIDS? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 28 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review, we present information relating to the effectiveness and safety of the following interventions: advice to avoid prone sleeping; advice to avoid tobacco-smoke exposure; advice to avoid soft sleeping surfaces; advice to avoid overheating or overwrapping; advice to avoid bed sharing; advice to breastfeed; advice to promote soother/pacifier use; and advice to promote room sharing (without bed sharing).
Key Points
Sudden infant death syndrome (SIDS) is the sudden death of an infant under 1 year of age that remains unexplained after review of the clinical history, examination of the scene of death, and postmortem. The incidence varies among countries, with 0.32 cases being reported per 1000 live births in England and Wales in 2004, and 0.55 cases per 1000 in the US for the same period.We found no systematic review or RCTs studying the effects of interventions to reduce the risk of SIDS due to the obvious difficulties in performing these trials. Therefore, we report only observational evidence in this review.
Campaigns that have advised avoiding prone sleeping have significantly reduced the incidence of SIDS. Observational studies have additionally shown that the incidence of prone positioning is dramatically reduced after national advice campaigns.
Advice to avoid tobacco-smoke exposure seems to reduce the incidence of SIDS. National campaigns that advise mothers to avoid tobacco-smoke exposure also seem to lead to a reduction in maternal smoking rates.
Some campaigns included advice to avoid overheating, overwrapping, and bed sharing, and advice to breastfeed, although it is not clear whether this contributed to the observed reduction in SIDS.
We found no studies looking at the effects of advice to avoid soft sleeping surfaces, to promote soother/pacifier use, or to promote room sharing (without bed sharing).
PMCID: PMC2907828  PMID: 21726486
21.  Ethnic differences in mortality from sudden infant death syndrome in New Zealand. 
BMJ : British Medical Journal  1993;306(6869):13-16.
OBJECTIVES--To examine the factors which might explain the higher mortality from sudden infant death syndrome in Maori infants (7.4/1000 live births in 1986 compared with 3.6 in non-Maori children). DESIGN--A large nationwide case control study. SETTING--New Zealand. 485 infants who died of sudden infant death syndrome were compared with 1800 control infants. There were 229 Maori and 240 non-Maori cases of sudden infant death syndrome (16 cases unassigned) and 353 Maori and 1410 non-Maori controls (37 unassigned). RESULTS--Maori infants had 3.81 times the risk (95% confidence interval 3.06 to 4.76) of sudden infant death syndrome compared with non-Maori infants. The risk factors for sudden infant death syndrome within groups were remarkably similar. When Maori and non-Maori controls were compared the prevalence of many of the known risk factors was higher in Maori infants. In particular, mothers were socioeconomically disadvantaged, younger, and more likely to smoke and their infants were of lower birth weight and more likely to share a bed with another person. Multivariate analysis controlling for potential confounders found that simply being Maori increased the risk of sudden infant death syndrome by only 1.37 (95% CI = 0.95 to 2.01), not statistically significantly different from 1. Population attributable risk was calculated for prone sleeping position, maternal smoking, not breast feeding, and infants sharing a bed with another person. In total these four risk factors accounted for 89% of deaths from sudden infant death syndrome in Maori infants and 79% in non-Maori infants. CONCLUSION--The high rate of sudden infant death syndrome among Maori infants is based largely on the high prevalence in the Maori population of the major risk factors. Other risk factors, not related to ethnicity, probably explain remaining differences between Maori and non-Maori children.
PMCID: PMC1676357  PMID: 8435568
22.  Infant Sleeping Environment in South-Eastern Nigeria (Sleeping Place and Sleeping Position): A Preliminary Survey 
Journal of Tropical Medicine  2009;2009:283046.
Objective. To determine infant sleeping position/place and the factors associated with them in South-eastern Nigeria. Methods. this is a cross-sectional study on infant sleeping environment. Subjects were the mother/ infant pairs that attended the well baby clinics at the Institute of Child Health of the University of Nigeria Teaching Hospital, Enugu (ICH-UNTH), Mother of Christ Specialist Hospital (MCSH), Enugu and the Ebonyi State University Teaching Hospital (EBSUTH), Abakaliki. Results. Lying on the side was the most common (51.1%) and the least stable sleeping position. Only 36.6% of infants who slept in that position were likely to be found in the same position the following morning; lying supine was the most stable (74.1%). The difference in stability of sleeping positions was statistically significant (P < .01). Twenty six point seven percent of the mothers routinely lay their infants in prone position. On logistic regression, maternal parity was the only factor that was predictive of nonprone sleeping position (P = .01). Bed sharing, though common (66.9%), was more among the experienced (P = .03) and less educated mothers (P < .01). Conclusion. There is a high level of prone sleeping position and bed sharing among infants in this study site. The potential consequences of these are unclear. There is therefore a need to conduct local studies to clarify its implication.
PMCID: PMC2837316  PMID: 20309418
23.  HIV-1 Drug Resistance Emergence among Breastfeeding Infants Born to HIV-Infected Mothers during a Single-Arm Trial of Triple-Antiretroviral Prophylaxis for Prevention of Mother-To-Child Transmission: A Secondary Analysis 
PLoS Medicine  2011;8(3):e1000430.
Analysis of a substudy of the Kisumu breastfeeding trial by Clement Zeh and colleagues reveals the emergence of HIV drug resistance in HIV-positive infants born to HIV-infected mothers treated with antiretroviral drugs.
Nevirapine and lamivudine given to mothers are transmitted to infants via breastfeeding in quantities sufficient to have biologic effects on the virus; this may lead to an increased risk of a breastfed infant's development of resistance to maternal antiretrovirals. The Kisumu Breastfeeding Study (KiBS), a single-arm open-label prevention of mother-to-child HIV transmission (PMTCT) trial, assessed the safety and efficacy of zidovudine, lamivudine, and either nevirapine or nelfinavir given to HIV-infected women from 34 wk gestation through 6 mo of breastfeeding. Here, we present findings from a KiBS trial secondary analysis that evaluated the emergence of maternal ARV-associated resistance among 32 HIV-infected breastfed infants.
Methods and Findings
All infants in the cohort were tested for HIV infection using DNA PCR at multiple study visits during the 24 mo of the study, and plasma RNA viral load for all HIV-PCR–positive infants was evaluated retrospectively. Specimens from mothers and infants with viral load >1,000 copies/ml were tested for HIV drug resistance mutations. Overall, 32 infants were HIV infected by 24 mo of age, and of this group, 24 (75%) infants were HIV infected by 6 mo of age. Of the 24 infants infected by 6 mo, nine were born to mothers on a nelfinavir-based regimen, whereas the remaining 15 were born to mothers on a nevirapine-based regimen. All infants were also given single-dose nevirapine within 48 hours of birth. We detected genotypic resistance mutations in none of eight infants who were HIV-PCR positive by 2 wk of age (specimens from six infants were not amplifiable), for 30% (6/20) at 6 wk, 63% (14/22) positive at 14 wk, and 67% (16/24) at 6 mo post partum. Among the 16 infants with resistance mutations by 6 mo post partum, the common mutations were M184V and K103N, conferring resistance to lamivudine and nevirapine, respectively. Genotypic resistance was detected among 9/9 (100%) and 7/15 (47%) infected infants whose mothers were on nelfinavir and nevirapine, respectively. No mutations were detected among the eight infants infected after the breastfeeding period (age 6 mo).
Emergence of HIV drug resistance mutations in HIV-infected infants occurred between 2 wk and 6 mo post partum, most likely because of exposure to maternal ARV drugs through breast milk. Our findings may impact the choice of regimen for ARV treatment of HIV-infected breastfeeding mothers and their infected infants.
Trial Registration NCT00146380
Please see later in the article for the Editors' Summary
Editors' Summary
Globally, more than 2 million children are infected with the human immunodeficiency virus (HIV) that causes acquired immunodeficiency syndrome (AIDS), and half a million children are newly infected every year. These infections are mainly the result of mother-to-child transmission (MTCT) of HIV during pregnancy, labor and delivery, or through breastfeeding. MTCT can be greatly reduced by treating HIV-positive mothers and their babies with antiretroviral drugs (ARVs). Without ARVs, up to half of babies born to HIV-positive mothers become infected with HIV. This rate of transmission falls to below 5% if a combination of three ARVs is given to the mother throughout pregnancy. Unfortunately, this triple-ARV therapy is too expensive for use in the resource-limited countries where most MTCT occurs. Instead, many such countries have introduced simpler, shorter ARV regimens such as a daily dose of zidovudine (a nucleoside reverse transcriptase inhibitor or NRTI) given to HIV-positive women during late pregnancy coupled with single-dose nevirapine (a non-nucleoside reverse transcriptase inhibitor or NNRTI) at the onset of labor, zidovudine and lamivudine (another NRTI) during labor and delivery, and single-dose nevirapine given to the baby at birth.
Why Was This Study Done?
More than 95% of HIV-exposed children are born in resource-limited settings where breastfeeding is the norm and is crucial for child survival even though it poses a risk of HIV transmission. Consequently, several recent studies have investigated whether MTCT can be further reduced by giving the mother ARVs while she is breastfeeding. In the Kisumu Breastfeeding Study (KiBS), for example, researchers assessed the effects of giving zidovudine, lamivudine, and either nevirapine or nelfinavir (a protease inhibitor) to HIV-infected women from 34 weeks of pregnancy through 6 months of breastfeeding. The results of KiBS indicate that this approach might be a safe, feasible way to reduce MTCT (see the accompanying paper by Thomas and colleagues). However, low amounts of nevirapine and lamivudine are transferred from mother to infant in breast milk and this exposure to ARVs could induce the development of resistance to ARVs among HIV-infected infants. In this KiBS substudy, the researchers investigate whether HIV drug resistance emerged in any of the HIV-positive infants in the parent study.
What Did the Researchers Do and Find?
In KiBS, 32 infants were HIV-positive at 24 months old; 24 were HIV-positive at 6 months old when their mothers stopped taking ARVs and when breastfeeding was supposed to stop. The researchers analyzed blood samples taken from these infants at various ages and from their mothers for the presence of HIV drug resistance mutations (DNA changes that make HIV resistant to killing by ARVs). They detected no resistance mutations in samples taken from 2-week old HIV-positive infants or from the infants who became infected after the age of 6 months. However, they found resistance mutations in a third and two-thirds of samples taken from 6-week and 6-month old HIV-positive infants, respectively. The commonest mutations conferred resistance to lamivudine and nevirapine. Moreover, resistance mutations were present in samples taken from all the HIV-positive infants whose mothers who had received nelfinavir but in only half those taken from infants whose mothers who had received nevirapine. Finally, most of the mothers of HIV-positive infants had no HIV drug resistance mutations, and only one mother-infant pair had an overlapping pattern of HIV drug resistance mutations.
What Do These Findings Mean?
These findings indicate that, in this KiBS substudy, the emergence of HIV drug resistance mutations in HIV-infected infants whose mothers were receiving ARVs occurred between 2 weeks and 6 months after birth. The pattern of mutations suggests that drug resistance most likely arose through exposure of the infants to low levels of ARVs in breast milk rather than through MTCT of drug-resistant virus. These findings need confirming but suggest that infants exposed to ARVs through breast milk—a situation that may become increasingly common given the reduction in MTCT seen in KiBS and other similar trials—should be carefully monitored for HIV infection. Providers should consider the mothers' regimen when choosing treatment for infants who are found to be HIV-infected despite maternal triple drug prophylaxis. Infants exposed to a maternal regimen with NNRTI drugs should receive first-line therapy with lopinavir/ritonavir, a protease inhibitor. The significance of the NRTI mutations such as M184V with regard to response to therapy needs further evaluation. The M184V mutation may result in hypersensitization to other NRTI drugs and delay or reverse zidovudine resistance. Given the limited availability of alternative drugs for infants in resource-limited settings, provision of the standard WHO-recommended first-line NRTI backbone, which includes 3TC, with enhanced monitoring of the infant to ensure virologic suppression, could be considered. Such an approach should reduce both illness and morbidity among infants who become HIV positive through breastfeeding.
Additional Information
Please access these Web sites via the online version of this summary at 10.1371/journal.pmed.1000430.
The accompanying PLoS Medicine Research article by Thomas and colleagues describes the primary findings of the Kisumu Breastfeeding Study
Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS
HIV InSite has comprehensive information on HIV/AIDS
Information is available from Avert, an international AIDS charity, on many aspects of HIV/AIDS, including information on children, HIV, and AIDS and on preventing mother-to-child transmission of HIV (in English and Spanish)
UNICEF also has information about children and HIV and AIDS (in several languages)
The World Health organization has information on mother-to-child transmission of HIV (in several languages), and guidance on the use of ARVs for preventing MTCT
PMCID: PMC3066134  PMID: 21468304
24.  Bed sharing when parents do not smoke: is there a risk of SIDS? An individual level analysis of five major case–control studies 
BMJ Open  2013;3(5):e002299.
To resolve uncertainty as to the risk of Sudden Infant Death Syndrome (SIDS) associated with sleeping in bed with your baby if neither parent smokes and the baby is breastfed.
Bed sharing was defined as sleeping with a baby in the parents’ bed; room sharing as baby sleeping in the parents’ room. Frequency of bed sharing during last sleep was compared between babies who died of SIDS and living control infants. Five large SIDS case–control datasets were combined. Missing data were imputed. Random effects logistic regression controlled for confounding factors.
Home sleeping arrangements of infants in 19 studies across the UK, Europe and Australasia.
1472 SIDS cases, and 4679 controls. Each study effectively included all cases, by standard criteria. Controls were randomly selected normal infants of similar age, time and place.
In the combined dataset, 22.2% of cases and 9.6% of controls were bed sharing, adjusted OR (AOR) for all ages 2.7; 95% CI (1.4 to 5.3). Bed sharing risk decreased with increasing infant age. When neither parent smoked, and the baby was less than 3 months, breastfed and had no other risk factors, the AOR for bed sharing versus room sharing was 5.1 (2.3 to 11.4) and estimated absolute risk for these room sharing infants was very low (0.08 (0.05 to 0.14)/1000 live-births). This increased to 0.23 (0.11 to 0.43)/1000 when bed sharing. Smoking and alcohol use greatly increased bed sharing risk.
Bed sharing for sleep when the parents do not smoke or take alcohol or drugs increases the risk of SIDS. Risks associated with bed sharing are greatly increased when combined with parental smoking, maternal alcohol consumption and/or drug use. A substantial reduction of SIDS rates could be achieved if parents avoided bed sharing.
PMCID: PMC3657670  PMID: 23793691
Prevention; Public Health; Epidemiology; Sids; Bed sharing
25.  Randomised trial of infant sleep location on the postnatal ward 
Archives of Disease in Childhood  2006;91(12):1005-1010.
To determine whether postnatal mother–infant sleep proximity affects breastfeeding initiation and infant safety.
Randomised non‐blinded trial analysed by intention to treat.
Postnatal wards of the Royal Victoria Hospital (RVI), Newcastle upon Tyne, UK.
64 newly delivered mother–infant dyads with a prenatal intention to breastfeed (vaginal deliveries, no intramuscular or intravenous opiate analgesics taken in the preceding 24 h).
Infants were randomly allocated to one of three sleep conditions: baby in mother's bed with cot‐side; baby in side‐car crib attached to mother's bed; and baby in stand‐alone cot adjacent to mother's bed.
Main outcome measures
Breastfeeding frequency and infant safety observed via night‐time video recordings.
During standardised 4‐h observation periods, bed and side‐car crib infants breastfed more frequently than stand‐alone cot infants (mean difference (95% confidence interval (CI)): bed v stand‐alone cot = 2.56 (0.72 to 4.41); side‐car crib v stand‐alone cot = 2.52 (0.87 to 4.17); bed v side‐car crib = 0.04 (−2.10 to 2.18)). No infant experienced adverse events; however, bed infants were more frequently considered to be in potentially adverse situations (mean difference (95% CI): bed v stand‐alone cot = 0.13 (0.03 to 0.23); side‐car crib v stand‐alone cot = 0.04 (−0.03 to 0.12); bed v side‐car crib = 0.09 (−0.03–0.21)). No differences were observed in duration of maternal or infant sleep, frequency or duration of assistance provided by staff, or maternal rating of postnatal satisfaction.
Suckling frequency in the early postpartum period is a well‐known predictor of successful breastfeeding initiation. Newborn babies sleeping in close proximity to their mothers (bedding‐in) facilitates frequent feeding in comparison with rooming‐in. None of the three sleep conditions was associated with adverse events, although infrequent, potential risks may have occurred in the bed group. Side‐car cribs are effective in enhancing breastfeeding initiation and preserving infant safety in the postnatal ward.
PMCID: PMC2083001  PMID: 16849364

Results 1-25 (1004674)