An infant has a fivefold increased risk of sudden infant death syndrome (SIDS) when they share their bed with their parents, according to an analysis.
The authors of this analysis estimate that around 88 percent of all SIDS deaths while bed sharing would not have occurred if it had been avoided.
The results show that even when neither parent smoked, and the baby was less than 3 months old, breastfed and the mother did not drink or take drugs, the risk of SIDS was five times higher than if the baby had slept in a cot next to their parents' bed.
The risk of SIDS while bed sharing decreased as the age of the infant rose, but if either parent was a smoker or the mother had drunk alcohol (two or more units in the last 24 hours) or used illegal drugs, including cannabis, at any time since the child was born, the risk was greatly increased.
Risks of bed sharing had been reported in different ways, so Professor Bob Carpenter, of the London School of Hygiene and Tropical Medicine, led the study combining individual data from five published data sets from the UK, Europe and Australasia. It includes data on 1472 SIDS cases and 4679 controls and is the largest ever individual level study of the problem.
It revealed that one or both parents of 22.2 percent of the infants who had died from SIDS had been sleeping with their child at the time of death, while 9.6 percent of the parents in the control group had awoken the morning of the interview in the same bed as their child.
Over the past 10 years, there has been a marked increase in bed sharing and the authors now estimate that around 50 percent of SIDS cases occur while bed sharing, more than double the figure found in the study.
The findings of the analysis have been published online in BMJ Open.
