Tobacco smoking is endocrine-disrupting and may interfere with vitamin D endocrine systems (VDES), but supporting evidence is limited and inconsistent. Also, there is a lack of evidence on whether the association between tobacco smoke exposure and VD levels exhibit temporal variation. Data from the National Health and Nutrition Examination Survey was used to evaluate the association between tobacco smoke exposure and VD levels among US general participants from 2001 to 2014. 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 years), ethnicity/race, or body mass index (BMI) groups were disproportionately impacted. During 2001–2004, a decrease in both serum cotinine and passive smoking prevalence was observed, with a stabilized active smoking rate. The estimates for the association between tobacco smoke exposure and suboptimal VD levels increased over the study period. Overall results indicated that serum cotinine was negatively associated with 25(OH)D in all participants. Tobacco smoke exposure, including both active and passive smoking exposure, was associated with increased risk of VD deficiency. Moreover, active smoking was additionally related to enhanced risk of VD inadequacy. These associations showed some age and gender differences, with consistent and stronger associations observed in female adults. In contrast, effects of tobacco smoke exposure on VD levels were mostly negative or non-significant among children and adolescents aged 3–19 years. The percentage of US general population with active smoking exposure stabilized over the 14-year period and was still high. Tobacco smoke exposure may disrupt vitamin D levels with an increasing temporal trend in the risk. Our results also provided initial evidence of smoking exposure on VD intoxication, which needs to be further verified. Convincing studies have linked tobacco use 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 inconsistent, and there were no researches to date that estimated the temporal variation of the association as well as the effects of smoke exposure on VD intoxication. This study analyzed national survey data, to evaluate the temporal trends in effects of tobacco smoke exposure on VD levels over a decade, and to comprehensively assess the impacts of tobacco smoke exposure on VD levels across specific subgroups. The evidence suggests that the prevalence of active smoking exposure stabilized over the 14-year period and was still high. Moreover, tobacco smoke exposure may disrupt vitamin D levels among general population, with an increasing temporal trend and age-, gender-differences in risk. Supplementary Information...

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ObjectiveSedentary behaviour is associated with increased cancer risk. We aim to assess the associations of domain-specific and total sedentary behaviour with risk of endometrial cancer, with additional attention paid to potential differences in adjustment strategy for obesity and physical activity.DesignA systematic review and meta-analysis was conducted in accordance with the guidelines of Preferred Reporting Items for Systematic Reviews (PRISMA) and Meta-Analyses and the Meta-analysis of Observational Studies in Epidemiology (MOOSE).Data sourcesPubMed, Embase and MEDLINE databases were searched up to 28 February 2023, supplemented by grey literature searches.Eligibility criteria for selecting studiesObservational human studies evaluating the association between sedentary behaviour and endometrial cancer.Data extraction and synthesisTwo reviewers extracted data and conducted the quality assessment based on Newcastle-Ottawa Scale (NOS) independently. We used a random-effects model with inverse variance approach to pool the estimates. The extent of heterogeneity was quantified with theI2statistics.ResultsSixteen studies were included in the systematic review. Fourteen studies involving 882 686 participants were included in the meta-analysis. The pooled relative risks (RRs) for high versus low level of overall sedentary behaviour was 1.28 (95% CI: 1.14 to 1.43;I2=34.8%). The increased risk regarding specific domains was 1.22 (95% CI: 1.09 to 1.37; I2=13.4%, n=10) for occupational domain, 1.34 (95% CI: 0.98 to 1.83; I2=53.7%, n=6) for leisure-time domain and 1.55 (95% CI: 1.27 to 1.89; I2=0.0%, n=2) for total sedentary behaviour. Larger pooled RRs were observed among studies with adjustment for physical activity and studies without adjustment for body mass index.ConclusionsHigher levels of sedentary behaviour, total and occupational sedentary behaviour in particular, increase the risk of endometrial cancer. Future studies are needed to verify domain-specific associations based on objective quantification of sedentary behaviour, as well as the interaction of physical activity, adiposity and sedentary time on endometrial cancer.

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.