National Trends in Tobacco Smoke Exposure and its Disruption on Vitamin D Levels Among U.S. Population, 2001-2014

Background: Persuasive evidence suggests that tobacco smoking is endocrine-disrupting and may interfere with vitamin D (VD) endocrine systems, but supporting research is limited and results vary greatly.Methods: Data from the National Health and Nutrition Examination Survey, 2001-2014, was used to evaluate the trends in tobacco smoke exposure among U.S. general participants aged ≥3 yr (n=49338). We examined the linear association between serum cotinine and 25(OH)D concentrations, as well as relationship between tobacco smoke exposure categories (active, passive, non-smoking) with VD status (deficiency, inadequacy, sufficiency, intoxication), and assessed whether specific gender, age (3-11, 12-19, 20-59, ≥60 yr) or ethnicity/race groups were disproportionately impacted.Results: During 2001-2004, the trends of active smoking rates stabilized between 17.2% to 19.6%. Serum cotinine was significantly and inversely associated with 25(OH)D in adult participants (≥ 20 yr). Tobacco smoke exposure, including both active and passive smoking exposure, was associated with increased risk of VD deficiency in adults. Moreover, active smoking of adults was additionally related to enhanced risk of VD inadequacy. These associations showed somewhat gender difference, with consistent and stronger associations observed in female adults. In contrast, effects of tobacco smoke exposure on VD levels were mostly protective or non-significant among children and adolescents aged 3-19 yr.Conclusion: The percentage of U.S. general population with active smoking exposure stabilized over the 14-yr period and was still high. Tobacco smoke exposure may disrupt vitamin D levels. Our results also provided initial evidence of active smoking exposure on VD intoxication, which needs to be further verified.Implication: Convincing studies have linked tobacco use exposure, including active and passive smoking exposure, to dysfunctional VDES accompanied with declined serum levels of VD metabolites. However, evidence on the association between tobacco smoke exposure and VD status was rather limited, and there were no researches to date that estimated their relationship in children and adolescents. This study analyzed national survey data, to evaluate the national trends in tobacco smoke exposure over a decade, and to comprehensively assess the impacts of tobacco smoke exposure on VD levels across specific gender-, age- and ethnicity/race- groups. The evidence suggests that the prevalence of active smoking exposure stabilized over the 14-yr period and was still high. Moreover, tobacco smoke exposure may disrupt vitamin D levels among general population, with age- and gender- differences observed.