Sudden infant death syndrome in Tasmania, 1975-81.

A survey of all infants dying from the Sudden Infant Death Syndrome (SIDS) in Tasmania from 1975 to 1981 showed an incidence of 4.4 per 1000 live births; SIDS comprised 68% of infant deaths. The peak incidence of death was at 3 months of age and the following factors were significant: male sex, gestation less than 38 weeks, birthweight less than 2500 g, unmarried mothers, maternal age below 24 years and unskilled fathers. Analysis of these factors in combination showed each to be independently significant. SIDS was more frequent in the southern and western regions of Tasmania, and there was a higher incidence of death in the colder months in infants over 13 weeks of age. The monthly incidence of SIDS was inversely proportional to the monthly mean temperature in Tasmania and directly proportional to monthly hospital admissions for respiratory infections and apnoea. However, admissions for apnoea were more common in infants under 14 weeks of age. From these observations it is suggested that cold and respiratory infections are associated with the onset of SIDS in older infants.