Sudden infant deaths and seasonality in Tasmania, 1970-1976.

Analyses of monthly minimum temperatures and daily minimum temperatures show that significantly more Sudden Infant Deaths and 'pneumonitis' deaths occur in colder conditions in southern Tasmania. Low minimum monthly and low minimum daily temperatures 'explain' part of the observed winter seasonal peak of deaths. However, a sharp change of temperature over 24 hours, either upwards or downwards, is associated with fewer deaths than occurred when little or no change of temperature had been experienced. Utilising the additional data of the Tasmania-wide series it is shown that the winter seasonal effect is especially evident in infants over 3 months of age compared with those aged only 0-3 months, in whom seasonal variation did not occur.