The epidemiology of sudden infant death in upstate New York.

The epidemiology of sudden infant death among infants born during 1974 to mothers residing in upstate New York was studied. Death-certificate characteristics for 190 infants with sudden infant death syndrome (SIDS) are compared with those for 434 infants dying of other causes in the same age range. The overall incidence of SIDS was 1.43 per 1,000 live births. No relationship was found between SIDS rate and population density. The SIDS deaths peaked in January, with an overall seasonal pattern compatible with that of viral respiratory infections. The SIDS infants were more likely to die during sleeping hours than infants dying suddenly of other causes. Their age at death distribution is significantly different from that of other infant deaths. Progress in understanding sudden death in infancy is still hampered by the lack of positive diagnostic criteria.