Public health policy on bed sharing and smoking in the sudden infant death syndrome.

AIMS

Further develop New Zealand public health policy on infant bed sharing by quantifying the number of sudden infant death syndrome (SIDS) cases attributable to bed sharing among infants of smoking and nonsmoking mothers.

METHODS

A large nation-wide case control study covering a region with 78% of all births in New Zealand during 1987-90. Interviews were completed with parents of 393 (81.0% of total) cases who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region.

RESULTS

The proportion of control infants who usually bed shared in the last 2 weeks was 65.7% in Maori, 73.7% in Pacific Island people and 35.5% in Europeans (44.5% in all ethnic groups combined, and half of these for less than 2 hours per night). There was an interaction between maternal smoking and infant bed sharing on the risk of sudden infant death separately in Maori, Pacific Island and European infants with the risk being highest in infants exposed to both risk factors. 26% of SIDS deaths were explained by bed sharing among infants of smoking mothers (who comprised 16% of the total infant population) and 3% by bed sharing among infants of non-smoking mothers (28% of total infant population).

CONCLUSION

Infant bed sharing is common. The majority of SIDS deaths that are attributed to be sharing occur among infants of smoking mothers. A policy which advises all infants not to bed share is estimated to potentially save an extra 3% of SIDS compared to a policy targeted only on infants of smoking mothers. If public attitudes are favorable to bed sharing, there could be a marginal cost (against its acceptance) by including infants of non-smoking mothers in the recommendation not to bed share. These findings should not be interpreted as indicating that bed sharing where the mother is a nonsmoker is safe or protective against SIDS.