[Favourite sleeping positions among infants in the county of Roskilde. Is there a connection with sudden, unexplained...

The purpose of this study was to investigate the distribution of the favourite sleeping positions and other possible risk factors for SIDS among infants in a Danish county, and to compare the distribution af sleeping positions with the sleeping positions reported in SIDS-cases from the same district. Information about favourite sleeping positions at the age of one month and four months was collected by interviews with parents, performed consecutively by health visitors at the routine examinations of 174 infants aged eight months. Information about sex, birthweight, gestational age, complications of delivery, mother's age and maternal smoking in pregnancy was collected for each child from the Birth Registration form. Thirty-two SIDS-cases from the 10 year period 1982-91, mostly based on police reports, were analysed retrospectively as regards sleeping positions and other possible risk factors. The distribution of different sleeping positions at the age of one month/four months was: prone 59%/52%, lateral 39%/41%, supine 2%/6%. There was a significant negative correlation between birthweight and use of the prone position. Among the SIDS-cases, the prone sleeping position was reported in 18 of 21 cases (86%), where this information was available. In conclusion, the prone sleeping position seemed to be associated with an increased risk of SIDS (estimated OR 4.1) but some of this difference can be accounted for by the more frequent use of this position among children with low birthweight and other risk factors.