Racial differences in the impact of maternal smoking on sudden unexpected infant death

Background: Prenatal smoking increases the risk of Sudden Unexpected Infant Death (SUID). Whether exposure patterns and associations differ by race requires further study. Objectives: Determine if patterns of exposure and associations between SUID and maternal smoking before and during pregnancy differ by race. Methods: Using U.S. National Center for Health Statistics linked birth/infant death files 2012–2013, we documented SUID by smoking duration and race. Maternal smoking history: never, pre-pregnancy only, and pre-pregnancy plus first, first, second, or all trimesters. Results: Smoking was more common in non-Hispanic White (NHW) than non-Hispanic Black (NHB) mothers and more evident for both in SUID cases. The most common exposure duration is from before and throughout pregnancy (SUID: 78.3% NHW, 66.9% NHB; Survivors: 60.22% and 53.96%, respectively). NHB vs. NHW SUID rates per 1000 live births were 1.07 vs. 0.34 for non-smokers and 3.06 and 1.79 for smokers, ORs trended upward for both with increasing smoking duration. Conclusion: Fewer NHB mothers smoked, but both NHB and NHW groups exhibited a dose-response relationship between smoking duration and SUID. The most common duration was from before to the end of pregnancy, suggesting difficulty in quitting and a need for effective interventions.