A competing risk model of sudden infant death syndrome incidence in two US birth cohorts

To compare changing incidence and changing risk factors associated with sudden infant death syndrome (SIDS) in the 1989 and 1996 US birth cohorts.

All available singleton births over 500 g from the 1989 linked birth-infant death file and the 1996 and 1997 Perinatal Mortality files were examined. A log-logistic survival model was used to explicitly account for declining competing risks among low birth weight infants.

Controlling for maternal prenatal smoking and other confounders, SIDS incidence declined by >33% between the 2 survey years (adjusted odds ratio = 0.628 with 95% CI [0.598, 0.660]). Self-reported declines in maternal prenatal smoking were also associated with significant declines in SIDS incidence. African American infants and infants born weighing <1000 g experienced increased relative risk compared with non-Hispanic white infants born weighing >2500 g. Hispanic/Latino infants had significantly lower SIDS risk than non-Hispanic white infants in both years. Accounting for declining competing risks and other factors, relative SIDS risks among infants born between 500 and 1000 g increased over the study period.

SIDS incidence sharply declined between 1989 and 1996. High incidence of SIDS in African Americans and increased relative SIDS risk for infants born weighing <1000 g require increased attention from clinicians and public health policy makers.