Associations Between Sources of Secondhand Smoke Exposure and Overweight and Obesity Among Chinese School-Aged Youth.

BACKGROUND: The relationship between secondhand smoke exposure and obesity is still a matter of debate, and few studies have considered the settings of exposure when exploring this relationship. We aimed to examine the associations of secondhand smoke exposure in different places with overweight and obesity among Chinese children and adolescents. METHODS: We used data from the Shandong Provincial Student Common Diseases and Health Influencing Factors Survey conducted in 2021. Secondhand smoke exposure in different places was assessed using a standardized questionnaire. The associations of secondhand smoke exposure with overweight and obesity were examined using multivariate logistic regression analyses. A total of 122 509 children and adolescents (boys: 51.3%) aged 8-18 years were included. RESULTS: The body mass index (BMI) level and the prevalence of overweight and obesity were higher among children and adolescents with exposure to secondhand smoke compared with those without exposure (BMI: 21.6 ± 4.7 vs. 21.1 ± 4.4 kg/m2; overweight: 20.8% vs. 20.0%; obesity: 21.1% vs. 18.8%). Children and adolescents with exposure to secondhand smoke were more likely to have overweight (in any place: odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.06-1.13; at home: OR = 1.10, 1.06-1.14; in school: OR = 1.09, 1.02-1.15; in other public places: OR = 1.06, 1.03-1.10) and obesity (in any place: OR = 1.19, 1.15-1.23; at home: OR = 1.21, 1.17-1.26; at school: OR = 1.27, 1.20-1.35 and in other public places: OR = 1.12, 1.08-1.16) after adjustment for potential covariates. CONCLUSIONS: Secondhand smoke exposure was positively associated with overweight and obesity, regardless of exposure location. These findings underscore the importance of a collaborative effort for society, educational institutions and families to create a comprehensive smoke-free environment for children and adolescents.