Gender and educational stage-specific association of birth weight with overweight and obesity among children and adolescents aged 7-18 years: a school-based cross-sectional study

Objectives To investigate the associations between birth weight and overweight/obesity in school-aged children and adolescents according to different gender and educational stages, and explore the interactions among the lifestyle factors.Design Cross-sectional study.Setting Henan Province in China.Participants A total of 27 009 children and adolescents aged 7-18 years were included.Primary outcome measures Anthropometric parameters were measured and characteristics were collected by questionnaires. Logistic regression analysis was used to estimate the ORs and corresponding 95% CIs of overweight/obesity with birth weight. The relative excess risk due to interaction (RERI) and the attributable proportion of interaction (AP) indices were used to measure additive interaction.Results In the adjusted logistic regression models, the overall population with high birth weight (HBW) (adjusted ORs 2.866, 95% CI 1.563 to 3.728) had an increased risk of overweight/obesity compared with those with normal birth weight (NBW), and the associations differed by gender-specific and educational stage-specific factors. When stratified by gender, children and adolescents with HBW had a higher risk of overweight/obesity as compared with the NBW group (adjusted ORs 2.582 and 2.356; 95% CIs 1.413 to 3.579 and 1.097 to 2.934, boys and girls, respectively). According to different educational stages, HBW was positively associated with an increased risk of overweight/obesity compared with the NBW group. The adjusted ORs of the three groups were 2.757 (95% CI 1.483 to 3.658), 2.317 (95% CI 1.451 to 2.795) and 2.216 (95% CI 1.532 to 2.873), respectively. In addition, we found the HBW group with insufficient physical activity time had significantly higher risk of overweight/obesity (OR 2.165, 95% CI 1.352 to 3.378) in the overall population. As expected, a significant additive interaction was found between birth weight and insufficient physical activity time (RERI 2.289, 95% CI 0.678 to 3.576; AP 0.723, 95% CI 0.521 to 1.126).Conclusions HBW was significantly associated with an increased risk of overweight/obesity in school-aged children and adolescents, and the associations differed by gender-specific and educational stage-specific factors. Notably, HBW possibly interplayed synergistically with insufficient physical activity time to increase the risk of overweight/obesity across gender and educational stages.