Evid Based Nurs 10:119 doi:10.1136/ebn.10.4.119
  • Causation

Review: bed sharing between parents and infants exposed to smoke may increase the risk of sudden infant death syndrome

 Q What are the benefits and harms of children <2 years of age sharing a bed with a parent or other adult?


GraphicData sources:

Medline, CINAHL, HealthSTAR, PsycINFO, Cochrane Library, Turning Research Into Practice database, and Allied and Alternative Medicine (1993 to January 2005).

GraphicStudy selection and assessment:

English language, case–control and prospective cohort studies that evaluated the practice of bed sharing between adults and children 0–2 years of age. 17 case–control studies (3711 cases and 11 349 controls) and 10 cohort studies (n not reported) met the selection criteria. Quality assessment of individual studies was done using the Newcastle-Ottawa scale.


sudden infant death syndrome (SIDS), breast feeding, parent−child attachment (bonding), and awakenings during sleep.


Meta-analysis was not done because of heterogeneity across studies. Bed sharing increased the risk of SIDS in some case–control studies but not others (table). The risk of SIDS with bed sharing was greater in infants exposed to cigarette smoke (range of odds ratios 2.3 to 12) than in those not exposed (range of odds ratios 0.4 to 1.7). The association between bed sharing and SIDS was stronger in younger infants (3 case–control studies) and those with a history of illness since birth (1 case–control study). Some evidence suggests a decreased association with SIDS for daytime bed sharing (1 case–control study) and breast feeding initiated at birth (1 case–control study). Bed sharing was associated with an increased duration of breast feeding (4 cohort studies), although causality is not clearly established. Infants who shared a bed had an increased number of night awakenings (3 cohort studies), which may be protective against SIDS. No study evaluating the effect of bed sharing on parent–child attachment was found.

Effect of bed sharing between infants and adults on risk of sudden infant death syndrome


Bed sharing between children <2 years of age and a parent or other adult may increase the risk of sudden infant death syndrome in children exposed to cigarette smoke. In non-smoking environments, the evidence for an association is not consistent.


  1. Linda O’Mara, RN, PhD
  1. McMaster University School of Nursing,
 Hamilton, Ontario, Canada

      The systematic review by Horsley et al examining the benefits and harms of bed sharing makes an important contribution to the literature because it is well done, comprehensive, and up to date. Although the overall rate of SIDS is decreasing to a reported 1 in 1000 live births,1 SIDS remains a leading cause of death in infants. In the US, the SIDS rates for infants of non-Hispanic black and American Indian mothers are more than double the rates for infants of non-Hispanic white mothers.2 Thus, there are major differences in death rates among population subgroups, and researchers should continue to seek an increased understanding of causes to aid in developing preventative strategies.

      The findings of Horsley et al strongly suggest that the increased risk of SIDS with bed sharing is greater in infants exposed to cigarette smoke than in those not exposed to smoke. Whether bed sharing is a risk factor for SIDS in infants in non-smoking environments remains less clear.

      Although it is not ideal to identify practice implications from research findings based on case–control and cohort studies, practice changes are warranted when randomised controlled trials are not a possibility. Public health messages should be developed to discourage bed sharing in homes where infants are exposed to cigarette smoke. Although the authors did not address the effects of sleeping in the same room, other studies indicate that the SIDS rate is halved when babies <6 months of age sleep in the same room as their caretakers.1 Sleeping close to the parents’ bed can, therefore, be strongly encouraged as a safe alternative to bed sharing.



      • For correspondence: Dr T Horsley, Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada. thorsley{at}

      • Sources of funding: City of Toronto and Toronto Public Health.

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