Unexpected death in infancy. An epidemiologic study in the Haifa district, Israel.

The incidence of unexpected death in infancy (UDI) (2 weeks-12 months) in the Haifa area is 1.17 per 1000 live births. We found a significant interethnic difference between Israeli Jews and Arabs. The incidence among Arabs was 4 per 1000, but was only 0.77 per 1000 among Jews (p < 0.01). When the UDI Jewish group was compared to both the group of infants dying of known causes and the surviving group, the only significant factors related to UDI were found to be: young maternal age and low maternal education. No such association was evident among Arabs. Following logistic regression analysis, low maternal age and low socioeconomic status, but not ethnicity, were significantly associated with UDI as compared to the non-UDI infants. In comparison to non-UDI, UDI was significantly more prevalent during the cold season. UDI incidence has apparently been stable over the past 15 years. Demographic risk factors are similar to those reported from other communities, and ethnicity is possibly mediated through those factors.