Association between birth weight and risk of abdominal obesity in children and adolescents: a school-based epidemiology survey in China

Abdominal obesity is becoming an increasingly serious public health challenge in children and adolescents, there remains controversial opinions on birth weight and risk of childhood abdominal obesity. This study aims to assess the association between birth weight and the risk of abdominal obesity in childhood, as well as to compare the associations among different sex and age groups. A total number of 30,486 (15,869 boys and 14,617 girls) participants aged 6-17 years old were included in this study. Participants were classified into five groups according to their birth weight. Waist-to-height ratio (WHtR) was used to define abdominal obesity. Fractional polynomial regression model was used to assess the association between birth weight and WHtR, and a multi-variable logistic regression model was applied to evaluate the risk of abdominal obesity in different birth weight groups. A J-shaped association was observed between birth weight and WHtR. Compared with birth weight of 2500-2999 g, high birth weight was associated with increased risk of abdominal obesity [OR (95% CI) for 3000-3499 g: 1.12(1.00-1.24); 3500-3999 g: 1.19(1.07-1.34); ≥4000 g: 1.42(1.24-1.62)]. No significant correlation was observed in children with birth weight ≤ 2499 g. Similar patterns were observed across different age groups. Abdominal obesity risk for high birth weight was particularly pronounced in boys compared to girls. Birth weight ≥ 3000 g, especially for boys, was associated with an elevated risk of abdominal obesity in childhood and may benefit from intervention to mitigate this risk.