Infant morbidity and mortality attributable to prenatal smoking in the U.S.

BACKGROUND: Although prenatal smoking continues to decline, it remains one of the most prevalent preventable causes of infant morbidity and mortality in the U.S.
PURPOSE: The aim of this study was to estimate the proportion of preterm deliveries, term low birth weight deliveries, and infant deaths attributable to prenatal smoking.
METHODS: Associations were estimated for prenatal smoking and preterm deliveries, term low birth weight (<2500 g) deliveries, sudden infant death syndrome (SIDS), and preterm-related deaths among 3,352,756 singleton, live births using the U.S. Linked Birth/Infant Death Data Set, 2002 birth cohort. The 2002 data set is the most recent, in which 49 states used the same standardized smoking-related question on the birth certificate. Logistic regression models estimated ORs of prenatal smoking for each outcome, and the prenatal smoking population attributable fraction was calculated for each outcome.
RESULTS: Prenatal smoking (11.5% of all births) was significantly associated with very (AOR=1.5, 95% CI=1.4, 1.6); moderate (AOR=1.4, 95% CI=1.4, 1.4); and late (AOR=1.2, 95% CI=1.2, 1.3) preterm deliveries; term low birth weight deliveries (AOR=2.3, 95% CI=2.3, 2.5); SIDS (AOR=2.7, 95% CI=2.4, 3.0); and preterm-related deaths (AOR=1.5, 95% CI=1.4, 1.6). It was estimated that 5.3%-7.7% of preterm deliveries, 13.1%-19.0% of term low birth weight deliveries, 23.2%-33.6% of SIDS, and 5.0%-7.3% of preterm-related deaths were attributable to prenatal smoking. Assuming prenatal smoking rates continued to decline after 2002, these PAFs would be slightly lower for 2009 (4.4%-6.3% for preterm-related deaths, 20.2%-29.3% for SIDS deaths).
CONCLUSIONS: Despite recent declines in the prenatal smoking prevalence, prenatal smoking continues to cause a substantial number of infant deaths in the U.S. Published by Elsevier Inc.