The joint effect of vitamin-D status and tobacco exposure on overweight and obesity in children

This study aimed to explore the combined effects of serum vitamin-D level and tobacco exposure on the risk of overweight and obesity in children. This cross-sectional study analysed the data of 11 636 children aged 2-17 years from the National Health and Nutrition Examination Surveys database between 2007 and 2018. Univariable and multivariate weighted logistic regression models were used to analyse the associations of serum vitamin-D or cotinine levels with overweight and obesity in children as well as the combined effects of serum vitamin-D and cotinine on the risk of overweight and obesity in children. Subgroup analysis was performed in terms of gender, age, race and household smokers. OR with corresponding 95% CI was presented. The elevated risk of overweight and obesity in children was found in those with serum vitamin-D< 20 ng/ml (OR = 1<middle dot>44, 95% CI: 1<middle dot>29, 1<middle dot>61). Also, the odds of overweight and obesity in children was 1<middle dot>14 (OR = 1<middle dot>14, 95% CI: 1<middle dot>01, 1<middle dot>29) in children with cotinine >= 0<middle dot>05 ng/ml. Relative to participants with serum vitamin-D >= 20 ng/ml and cotinine < 0<middle dot>05 ng/ml, increased risk of overweight and obesity was identified in those with serum vitamin-D< 20 ng/ml and cotinine < 0<middle dot>05 ng/ml (OR = 1<middle dot>45, 95% CI: 1<middle dot>26, 1<middle dot>68) and serum vitamin-D<20 ng/ml and cotinine >= 0<middle dot>05 ng/ml (OR = 1<middle dot>62, 95% CI: 1<middle dot>38, 1<middle dot>91). Serum vitamin-D and cotinine exposure had combined effects on the risk of overweight and obesity in children.