State ENDS taxes and cigarette smoking in two-parent households

BACKGROUND: Exposure to secondhand smoke causes harm in children. Fortunately, smoking prevalence, and therefore exposure to secondhand smoke, has been declining for generations. However, states shifting policy targets to electronic nicotine delivery systems (ENDS) through taxes and regulations may have unintended consequences. How ENDS taxes impact childhood exposure to cigarette smoking remains unknown. METHODS: We analyzed National Survey of Children's Health data for two-parent households (2016-2024). Outcomes were 1-parental smoking status and 2-smoking behavior inside the home. The exposure variable was a standardized measure of ENDS taxes (dollar-per-milliliter). Two-way fixed-effect linear-probability models adjusted for household sociodemographic factors, and incorporated robust standard errors and analytic sampling weights. Subgroup analyses stratified by parental education. Marginal analysis estimated the average association between a $1 increase in ENDS tax and the probability of a child's exposure to parental smoking. RESULTS: The sample of 291,667 children represented 484.6 million weighted child-years. 13% of children lived with an adult who smoked and 2% were exposed to smoking inside the house. We found that a $1 ENDS tax increase was associated with a 0.51 (CI = 0.09, 0.94) percentage-point increase in household smoking and a 0.33 (CI = 0.08, 0.57) percentage-point increase in smoking inside the home. These associations were only found in lower-education households, reflected a 7% and 16% relative increase from baseline, and corresponded to an additional 1.5 million children exposed to secondhand smoke. CONCLUSIONS: Childhood exposure to secondhand smoke continues declining but ENDS taxes may have reversed progress for children in lower-education households.