Background: The aim of the study was to investigate bed sharing as a risk factor for sudden infant death syndrome (SIDS).
Material and methods: Firstly, SIDS cases examined at our institute in two six-year periods before and after the back-to-sleep campaign (1984-89 and 1998-2003) were investigated. Secondly, a case-control study was performed, an investigation of variables such as bed sharing, parental smoking and breast-feeding in the SIDS group from the latter period versus 244 live control infants.
Results: The age distribution of the SIDS victims in the two periods with high and low SIDS rates differed significantly (p = 0.004). In the latter period, fewer SIDS cases were seen in the classical distributional peak between the third and the fourth month of life, and a larger proportion of SIDS cases were seen within the first month of life. Furthermore, a smaller proportion of SIDS victims were found dead in the prone position (decrease from 89% to 49%, p < 0.001); and bed sharing at time of death occurred more frequently (increase from 7% to 35%, p < 0.001). In the case-control study, bed sharing was a significant risk factor for SIDS in infants aged 0-2 months (multivariate OR 5.3; 95 % CI 1.3-22, p = 0.02). Bed sharing with a smoking mother was associated with a 16-fold increased risk of SIDS (OR 16; 95% CI 2.1 - 118, p = 0.007). No relationship between bed sharing and SIDS was evident for age >2 months. Only 12% of the bed sharing SIDS victims aged <2 months where found in the prone position.
Interpretation: Bed sharing is associated with an increased risk of SIDS for infants <2 months of age. Particularly hazardous is bed sharing with a smoking parent.