OBJECTIVE: To describe the prevalence and associations of bed- and sofa-sharing in a biethnic UK birth cohort.
METHODS: We surveyed 3082 participants in the Born in Bradford birth cohort study by using a telephone interview when infants were aged 2 to 4 months. We asked families about sleep surface sharing behaviors, and other sudden unexpected death in infancy (SUDI)-related behaviors.
RESULTS: There were 15.5% of families that had ever bed-shared, 7.2% of families regularly bed-shared, and 9.4% of families had ever sofa-shared with their infants; 1.4% reported both. Regular bed-sharers were more commonly Pakistani (adjusted odds ratio [aOR] = 3.02, 95% confidence interval [CI] 1.96–4.66), had further or higher educational qualifications (aOR = 1.62, 95% CI 1.03–2.57), or breastfed for at least 8 weeks (aOR = 3.06, 95% CI 2.00–4.66). The association between breastfeeding and bed-sharing was greater among white British than Pakistani families. Sofa-sharing occurred in association with smoking (aOR = 1.79, 95% CI 1.14–2.80) and breastfeeding for more than 8 weeks (aOR = 1.76, 95% CI 1.19–2.58), and was less likely in Pakistani families (aOR = 0.21, 95% CI 0.14–0.31), or single-parent families (aOR = 0.50, 95% CI 0.29–0.87).
CONCLUSIONS: The data confirm that bed-sharing and sofa-sharing are distinct practices, which should not be combined in studies of unexpected infant deaths as a single exposure. The determinants of sleep-surface sharing differ between the UK Pakistani and UK majority communities, and from those of US minority communities. Caution is needed in generalizing SUDI/SIDS risk factors across populations with differing risk factor profiles, and care should be taken in adopting SUDI/SIDS reduction guidelines from other contexts.
- infant care
- Bradford Infant Care Study
- infant sleep
- Born in Bradford (BiB)
- aOR —
- adjusted odds ratio
- BiB —
- Born in Bradford
- BradICS —
- Bradford Infant Care Study
- CI —
- confidence interval
- OR —
- odds ratio
- SIDS —
- sudden infant death syndrome
- SUDI —
- sudden unexpected death in infancy
What’s Known on This Subject:
Parent-infant bed-sharing is a common behavior of breastfeeding mothers and various ethnic groups. Under certain circumstances, it is associated with an increased risk of sudden infant death. Blanket prohibitions against bed-sharing conflict with breastfeeding promotion and inhibit safe bed-sharing discussion.
What This Study Adds:
Bed-sharing and sofa-sharing were almost mutually exclusive. Pakistani families avoided sofa-sharing and hazardous bed-sharing, and have a very low rate of sudden infant death syndrome. White British families were more likely to smoke, drink alcohol, and sofa-share with their infants.
In many countries, parent-infant bed-sharing (sleeping together on the same surface) is common among breastfeeding mother-infant dyads,1–6 and a long-standing cultural practice for 1 or more minority groups.7–12 Studies have demonstrated an increased risk of sudden infant death syndrome (SIDS) associated with bed-sharing for infants of parents who smoke,13,14 no risk associated with bed-sharing with mother ± father, irrespective of maternal smoking status,11 whereas the European Concerted Action on SIDS investigation found a significantly increased risk of SIDS among the infants aged <9 weeks of nonsmoking mothers who bed-shared.15 In the Netherlands, the risk was increased only for infants <2 months of age.16 Gessner et al17 estimate the maximum potential risk for bed-sharing infants of nonsmoking mothers to be <1/10 000. Research has recently begun to document more closely the particular parental behaviors and shared sleep surfaces that present risks to infants.18
Although the evidence linking parent-infant bed-sharing with increased risk of SIDS or accidental infant death is inconsistent and contested,19,20 international guidelines have been dominated by recommendations to avoid bed-sharing. These guidelines have been heavily influenced by authorities in the United States (eg, Consumer Product Safety Commission,21 American Academy of Pediatrics22), who have advised against parents sleeping with their infants. This advice has been adopted in countries with different ethnic compositions, cultural practices, and SIDS profiles than the United States,23–25 even though other researchers have cautioned against imposing particular cultural values on diverse ethnic groups.3,26
Given the lack of agreement regarding which practices are associated with increased sudden unexpected death in infancy (SUDI)/SIDS risk when parents and infants sleep together, and the suggestion from previous studies that parent-infant sleep-sharing may be practiced in different ways according to ethnic and sociodemographic characteristics, it is imperative to have data on the actual sleep-sharing practices within any given community for whom guidance to parents is issued. The aim of this article is therefore to describe parent-infant sleep-sharing (bed-sharing and sofa-sharing) in a multiethnic urban population in the United Kingdom, to determine similarities and differences from bed-sharing practices in the United States and elsewhere, and to discuss implications for the formulation of infant “safe-sleep” recommendations.
The Born in Bradford (BiB) and Bradford Infant Care Study (BradICS) have been described elsewhere in detail.27,28 Briefly, the BiB birth cohort study included 14 000 pregnant women who gave birth in Bradford between May 2007 and May 2011. Women were recruited at 26 to 28 weeks’ gestation and completed a baseline questionnaire. The BradICS study reports on 3082 women who gave birth at the Bradford Royal Infirmary between June 2008 and September 2009. A total of 4131 mothers were contacted by telephone when their infants were 2 to 4 months of age and 3082 completed a telephone interview on infant care practices; 84% of women completing the telephone survey had complete baseline survey data (80% of the BiB sample completed the baseline survey). Analysis in this article is restricted to white British and Pakistani women who completed the BradICS telephone survey, the BiB baseline questionnaire, and had a singleton birth at the Bradford Royal Infirmary (n = 2180). The characteristics of the sample can be found in Table 1.
Three self-reported outcome measures were used: ever bed-share, regular bed-share, and ever sofa-share. All mothers were asked “Does your baby sleep in your bed when you are asleep?” If the mother responded “Rarely (once or twice),” “Occasionally (less than once a week),” “Regularly (twice or more per week),” or “Every night,” then they were classified as ever bed-share. Regular bed-share was defined as responding “Regularly” or “Every night” to this question. Mothers were asked, “Has the mother ever fallen asleep with the baby on a sofa or armchair?” Women were defined to ever sofa-share if they responded “Once,” “Occasionally,” or “Regularly.” Mothers were excluded from analysis if the response to either of these questions was missing (n = 7).
Potential Risk Factors
Several covariables, available from the baseline questionnaire, the hospital birth record, or the BradICS telephone survey, were included as potential risk factors in our analysis. The variables included were those previously shown to be associated with bed- or sofa-sharing and SUDI/SIDS risk in other populations. Ethnicity was self-defined by the mother when completing the baseline questionnaire. Other variables from the baseline questionnaire included language in which the questionnaire was completed, marital and cohabitation status, mother’s highest education qualification, Index of Multiple Deprivation based on postcode of residence at registration to the study (an area-based measure of average deprivation where areas are assigned scores based on measures in 7 domains; participant postcodes are mapped directly to Index of Multiple Deprivation scores for the area). Variables from the birth record included maternal age at delivery, parity, infant’s birth weight, and gestational age. Potential risk factors reported as part of the BradICS study were the following: mother currently smokes, father currently smokes, mother drinks alcohol in the evenings, father drinks alcohol in the evenings, breastfeeding duration, infant sleeps in own room, and infant’s age at completion of questionnaire. If data were missing on any of the potential risk factors, they were excluded from analysis (n = 173); this resulted in 2000 mothers being included in the analysis: 885 (44.3%) white British and 1115 (55.8%) Pakistani. We did not have access to data regarding maternal prenatal smoking. In general, fewer than 4% of Pakistani women smoked before pregnancy.
Univariable logistic regression was used to investigate the association between each of the potential risk factors and the 3 outcomes (ever bed-share, regular bed-share, and ever sofa-share).
Multivariable models were constructed using a backward stepwise procedure. All variables with a significance level of P < .05 were included in the multivariable model and variables with a significance level of P > .1 were removed from the model. The final model was chosen when no further variables were eligible for entry to or removal from the model.
We hypothesized that there would be ethnic differences in the association between breastfeeding and cosleeping based on previous reports that bed-sharing is a general cultural practice among South Asians,29 but is principally associated with breastfeeding among white British mothers.1 We tested this hypothesis by assessing the interaction of ethnicity and breastfeeding duration in the final models for each of the outcomes.
In this UK biethnic sample, with a mean infant age of 16.2 weeks (SD 2.88 weeks), 15.5% of mothers ever bed-shared, 7.2% of mothers regularly bed-shared, and 9.4% of mothers ever sofa-shared with their infants (Table 2). Only a very small proportion of mothers both bed-shared and sofa-shared (1.4%).
The prevalence of bed-sharing (ever and regular) was greater for the Pakistani than the white British mothers, and the prevalence of sofa-sharing was lower (Fig 1). Logistic regression analyses indicate that those mothers who bed-shared with their infants were different from those who sofa-shared.
Univariable analyses (Table 3) demonstrated that mothers who ever bed-shared were more likely to (1) be Pakistani (odds ratio [OR] = 1.92, 95% confidence interval [CI] 1.48–2.48), (2) have further or higher educational qualifications (OR = 1.62, 95%CI 1.21–2.18), (3) be primiparous (OR = 1.40, 95% CI 1.03–1.90) or grand-multiparous (OR = 1.60, 95% CI 1.10–2.35), and (4) have breastfed for more than a week (OR = 1.48, 95% CI 1.03–2.13) or at least 8 weeks (OR = 3.51, 95% CI 2.63–4.69). These mothers were less likely to (1) be <20 years of age (OR = 0.50, 95% CI 0.25–0.98), (2) not be living with a partner (OR = 0.55, 95% CI 0.36–0.84), or (3) have their infant sleep in a room alone (OR = 0.59, 95% CI 0.38–0.92).
Adjusted odds ratios (Table 4) indicate that mothers who ever bed-shared with their infants were more likely to (1) be Pakistani (OR = 2.09, 95% CI 1.47–2.97), (2) be living with a partner (not married) (OR = 1.59, 95% CI 1.01–2.51), (3) be first-time mothers (OR = 1.46, 95% CI 1.06–2.02), and (4) have breastfed for at least 8 weeks (OR = 3.17, 95% CI 2.34–4.30).
Mothers who regularly bed-shared are a subset of those who ever bed-shared. Univariable analyses reflect many of the characteristics of the larger ever bed-share group in terms of ethnicity, maternal age, education, high parity, longer breastfeeding duration, and infant sleep location (see Table 3). In addition, mothers who regularly bed-shared were more likely to be non-English speakers (OR = 2.19, 95% CI 1.52–3.17), and less likely (1) to be unmarried but living with a partner (OR = 0.39, 95% CI 0.21–0.71), and (2) for the father to consume alcohol on a regular basis (OR = 0.45, 95% CI 0.22–0.94) (Table 3).
Adjusted odds ratios (Table 5) for variables that remained significant in the multivariable analyses indicate that mothers who regularly bed-share were more likely to (1) be Pakistani (OR = 3.02, 95% CI 1.96–4.66), (2) have further or higher educational qualifications (OR = 1.62, 95% CI 1.03–2.57), and (3) have breastfed for at least 8 weeks (OR = 3.06, 95% CI 2.00–4.66).
Mothers who sofa-shared with their infants had characteristics different from those who ever or regularly bed-shared. Univariable analysis (Table 3) found sofa-sharing mothers (1) to be unmarried but cohabiting with a partner (OR = 2.14, 95% CI 1.51–3.03), (2) to be smokers (OR = 2.21, 95% CI 1.48–3.30), (3) to consume alcohol regularly (OR = 2.87, 95% CI 1.88–4.37), (4) to know their infant’s father consumes alcohol regularly (OR = 2.99, 95% CI 2.07–4.32), and (5) to have their infant sleep in his or her own room (OR = 2.44, 95% CI 1.68–3.55). Sofa sharers were significantly less likely to be Pakistani (OR = 0.24, 95% CI 0.17–0.34) and non-English speakers (OR = 0.39, 95% CI 0.23–0.65).
Adjusted ORs (Table 6) for variables that remained significant in the multivariable analyses indicate that mothers who ever sofa-shared with an infant were more likely to be (1) smokers (OR = 1.79, 95% CI 1.14–2.80) or (2) those who breastfed for more than 1 week (OR = 1.56, 95% CI 1.04–2.35) or 8 weeks (OR = 1.76, 95% CI 1.19–2.58) and less likely to be Pakistani (OR = 0.21, 95% CI 0.14–0.31) or single mothers without a partner (OR = 0.50, 95% CI 0.29–0.87).
Ethnicity, Breastfeeding, and Bed-Sharing
Women who never breastfed, or did so for less than 1 week, had the lowest proportions of all forms of sleep-sharing (Fig 2); however, in multivariable analysis, for ever bed-sharing, only those who breastfed for 8 weeks or more had a significant increase (OR = 3.17, 95% CI 2.34–4.30); those who breastfed for fewer than 8 weeks were not significantly different from those who did not breastfeed. The same was true for regular bed-sharing (breastfeeding for 8 or more weeks, OR = 3.06, 95% CI 2.00–4.66). For sofa-sharing, both breastfeeding groups ever shared a sofa more than those who did not breastfeed (1<8 weeks, OR = 1.04, 95% CI 1.04–2.35; 8 weeks or more, OR = 1.76, 95% CI 1.19–2.58) (Tables 4–6).
There is some evidence (Figs 3 and 4) of significant interaction between ethnicity and breastfeeding for ever bed-share (Wald P value for interaction term = .0979) and regular bed-share (Wald P value for interaction term = .0629); among women who breastfed for 8 or more weeks, white British women were more likely to ever and regularly bed-share than Pakistani women. This suggests that the association between bed-sharing and breastfeeding differs between the white British and Pakistani groups; however, the study was not specifically powered to detect this interaction.
Bed-Sharing Versus Sofa-Sharing
Mothers who bed-shared and sofa-shared with their infants comprised 2 groups with little overlap: very few mothers reported ever doing both. Multivariable logistic regression reveals that mothers who ever bed-shared were more likely to be Pakistani and first-time mothers. In contrast, mothers who ever sofa-shared were more likely to be white British, smokers, and living with a partner (not married). The only shared characteristic was that both groups included mothers who were more likely to have breastfed their infant: bed-sharers for at least 8 weeks and sofa-sharers for at least a week. That smokers may sofa-share is not surprising, given that they are specifically advised not to bed-share. That a group of breastfeeding mothers slept with their infants on sofas is consistent with the suggestion that some breastfeeding mothers are doing so in an attempt to avoid bed-sharing and inadvertently ending up sleeping with their infants in more hazardous situations.18
In the United Kingdom, researchers confirmed that bed-sharing in combination with smoking was associated with an increased risk of SIDS (OR = 12.35, 95% CI 7.41–20.59) but found no increase in risk for infants of parents who did not smoke (OR = 1.08, 95% CI 0.45–2.58).18 In 2006, the same team reported that over a 20-year period in the United Kingdom, the proportion of children who died of SIDS while sleeping with their parents rose from 12% to 50%, whereas the absolute number of SIDS deaths in the parental bed halved,30 and deaths of infants sleeping with their parents on a sofa increased, suggesting the most dangerous forms of sleep-sharing occur on sofas. A subsequent study on hazardous sleeping environments identified a significant interaction between sleep-sharing deaths and recent parental use of alcohol or drugs, and an increased proportion of SIDS infants who died while sleep-sharing on a sofa.18 The results of the current study support the conclusion that bed-sharing and sofa-sharing are practiced by different families under different circumstances. This heterogeneity would imply that bed- and sofa-sharing should not be combined in studies on infant sleep safety and SIDS, and casts doubt on the validity of previous studies where bed- and sofa-sharing have been combined.
Bed-Sharing, Ethnicity, and Sociodemographics
Parents who ever, or regularly, bed-shared in the current study were different from those who are characterized as bed-sharers in US studies of infant care. Our data show that infants of teenage mothers, single mothers, and fathers who consumed alcohol were the least likely to bed-share, whereas being the infant of a highly educated mother, a first-time mother, being breastfed, or being of Pakistani origin was associated with being more likely to bed-share. In the US Infant Feeding Practices Survey II, non-Hispanic black mothers were more likely to bed-share, as were lower-income women, unmarried women, and those who breastfed or smoked.31 Other US studies report the prevalence of bed-sharing in the United States is higher among mothers who are younger, never married, have less than a high school education, lower household incomes, are of black or Asian ethnicity, or live in southern states.2,12 McCoy et al2 reported that breastfeeding was associated with bed-sharing throughout the first 6 months of life; breastfeeding was significantly associated with bed-sharing among white non-Hispanic and Asian mothers, but not among black and Hispanic mothers. Young maternal age and unmarried status were associated with bed-sharing among black non-Hispanic mothers. In the United States, therefore, bed-sharing is often characterized as being practiced by young, unmarried, poorly educated mothers from minority ethnic groups living in circumstances of socioeconomic deprivation, and by mothers who breastfeed.
In the United Kingdom, as in the United States and New Zealand, bed-sharing is a cultural practice among particular ethnic minority groups. Associations between bed-sharing and SIDS are clearly demonstrated in particular cultures and circumstances. For example, in New Zealand bed-sharing is a common practice for both Maori and Pacific Islanders; however, only among the Maori population is bed-sharing linked with an increased risk of SIDS.8 The New Zealand Cot Death study revealed that bed-sharing was a SIDS risk in Maori families among whom maternal smoking was common, but not for Pacific Islanders who bed-share but do not smoke.8,13,32 In contrast, although the SIDS rate in the 1990s for US black infants was twice that for white infants, the Chicago Infant Mortality Study found no interaction between bed-sharing and maternal smoking either during pregnancy or postpartum; only bed-sharing with individuals other than parents was identified as a SIDS risk factor in multivariate analysis.3 South Asian infants in the United Kingdom generally,33 and Bradford specifically, have a lower SIDS rate than white British infants (0.2/1000 vs 0.8/1000 per annum, 2003–2008, Bradford and Airedale District, compiled by E.M., Bradford SUDI pediatrician, based on unpublished data from births and deaths registry). Pakistani-origin mothers in Bradford rarely smoke and neither mothers nor fathers consume alcohol.34 Pakistani infants were much more likely to bed-share than sofa-share. Ethnic minority practices with regard to sleep-sharing in the United Kingdom are therefore different from those defined among minority groups in New Zealand and the United States. It should not be assumed that families who bed-share have similar characteristics or outcomes across different geographic locations and care should be taken in generalizing the findings across different minority ethnic groups
Bed-Sharing and Breastfeeding
Multiple studies have documented an association between bed-sharing and breastfeeding.1–6,30,34–36 The current study reinforces this association and suggests that the interaction between breastfeeding and bed-sharing (especially regular bed-sharing) is greater for white British than Pakistani mothers who breastfeed for more than 8 weeks. It is beyond the scope of this study to determine causality or conclude that less bed-sharing would lead to less breastfeeding.
Although no case-control studies have calculated odds ratios for SIDS risk among breastfeeders who bed-share, breastfeeding has generally been found to reduce the risk of SIDS.25,37 Data from the Alaska Pregnancy Risk Assessment Monitoring System survey suggest a maximum potential risk of bed-sharing–related SIDS among nonsmoking mothers is likely to be <1 in 10 000.38 Caution should therefore be taken in making sweeping recommendations regarding the avoidance of bed-sharing, which does not appear to carry the same risk for all families, and may lead to unintended consequences, such as reduced breastfeeding, or adoption of more risky strategies, such as sofa-sharing. The American Academy of Pediatrics’ position on bed-sharing reflects the characteristics of mothers who sleep-share with infants in the United States and how they do so,22 yet not all sleep-sharing is inherently risky, even within the United States. Data from Alaska led researchers to conclude: “Among parents who do not use tobacco, alcohol or other drugs, sleeping with their infant is a perfectly reasonable and potentially beneficial option”.38
We are aware of the limitations of telephone survey methods, and the cross-sectional nature of our data28; however, this study also presents a major strength as the largest study of Pakistani families in the United Kingdom, who comprise the second largest minority ethnic group in the United Kingdom (after Indian families). Infants belonging to the highest SIDS-risk categories are underrepresented in the sample,28 and we may therefore have underestimated the extent of the relationship between some behaviors. Although we examined who was most likely to bed-share, we did not ask operational questions about bed-sharing, such as firmness of mattresses, and types of bedding used. Although Pakistani families in the United Kingdom have an increased prevalence of bed-sharing and a lower incidence of SIDS, it is beyond the scope of this study to determine if there are specific differences in the practices of bed-sharing that contribute to this association. We also cannot address reports that younger infants may be more vulnerable to bed-sharing–related SIDS than older infants, as we did not question families about the age of infants when sleep-sharing began.16
The current study supports the conclusions of previous studies that in the United Kingdom emphasis on unsafe sleep-sharing should predominantly target sofa-sharing and parental behaviors such as smoking and alcohol consumption.18
Our data led us to challenge the notion that assumptions and guidance about infant care practices can or should be exported from one cultural setting (such as the United States) to another (such as the United Kingdom). Evidence regarding the nature and extent of parent-infant sleep contact and related behaviors is crucial in ascertaining whether infants are at risk in shared-sleep scenarios, and in tailoring advice to parents.
This study supports the view that bed-sharing and sofa-sharing are distinct practices, which ought not to be combined in studies of unexpected infant deaths as a single exposure. Sleep-surface sharing practices in the UK Pakistani community differ from those of the UK majority community, and from those of minority communities in the United States. Health policy makers should exercise caution in generalizing SUDI/SIDS risk factors across populations with differing risk factor profiles. Care should therefore be taken in adopting SUDI/SIDS reduction guidelines from other contexts.
- Accepted November 11, 2011.
- Address correspondence to Helen L. Ball, MA, PhD, Professor of Anthropology, Parent-Infant Sleep Laboratory and Medical Anthropology Research Group, Dawson Building, South Rd, Durham University, Durham, UK DH1 3LE. E-mail:
Dr Ball is corresponding author and guarantor. She was involved in all aspects of study design and funding application, was a member of the Bradford Infant Care Study (BradICS) steering committee that oversaw project management and analysis, and was principal author of the submitted manuscript. Dr Moya conceived of the initial project, was involved in all aspects of study design and funding application, chaired the BradICS steering committee that oversaw project management and analysis, and contributed to and approved the submitted manuscript. Ms Fairley designed the analysis plan in collaboration with the BradICS steering committee, conducted all statistical analyses, drafted the methods and analysis sections of the manuscript, and approved the submitted manuscript. Ms Westman served as BradICS project manager, was involved in all aspects of study design and implementation, was a member of the BradICS steering committee, and contributed to and approved the submitted manuscript. Dr Oddie was involved in all aspects of study design and funding application, was a member of the BradICS steering committee that oversaw project management and analysis, and contributed to and approved the submitted manuscript. Dr Wright provided liaison with the larger Born in Bradford cohort study, was involved in all aspects of study design and funding application, was a member of the BradICS steering committee that oversaw project management and analysis, and contributed to and approved the submitted manuscript.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
FUNDED: Funded by the Foundation for the Study of Infant Deaths (FSID), United Kingdom.
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- Copyright © 2012 by the American Academy of Pediatrics