Secondhand smoke exposure is longitudinally associated with shorter parent-reported sleep duration during childhood

Background: Secondhand smoke exposure has been cross-sectionally associated with worse sleep health outcomes in children and shorter sleep duration in adolescents. Objectives: We assessed longitudinal and cross-sectional associations between secondhand smoke (SHS) exposure and shorter sleep duration in children from the Fragile Families and Child Wellbeing Study, a longitudinal birth cohort. We additionally examined whether associations would persist after controlling for potential confounders. Participants: Mothers (n = 4898) were recruited using a stratified random sample of large United States cities and oversampling for nonmarital births. Measurements: Mothers were asked about whether they smoked during pregnancy, whether their child spent time with someone who is smoking, and their child's weekday sleep duration. Sociodemographic factors, asthma diagnosis, and bedtime routines were assessed as potential confounders. Data collected at ages 3, 5, and 9 years were analyzed using multivariable regression models (N = 1912; 51.6% boys). Results: SHS exposure at age 3 predicted 15.0 fewer minutes at age 5 (P =.001) and 12.3 fewer minutes at age 9 (P =.003). SHS exposure at age 9 was cross-sectionally associated with 14.4 fewer minutes of sleep duration at age 9 (P =.002). Findings persisted after controlling for potential confounders. Conclusion: These results provide associational support for the hypothesis that SHS exposure may have long-term consequences for childhood sleep duration. Future studies should investigate the relationship between SHS exposure and shorter sleep duration using objective measurements of serum cotinine and sleep actigraphy and by exploring potential mechanisms.