Children’s birth weight and the risk of overweight and obesity in primary school children: a 4-year longitudinal study

Abstract Objective Childhood overweight (OW) and obesity (OB) have become a serious global health concern. Birth weight (BW) as one of the factors is associated with OB and chronic diseases in children and adults. However, it was not well studied in Zhejiang Province, China. This study was to investigate the association between BW and general OB and central OB in primal school children. Methods The Ningbo Youth Risk Behavior Survey is a school-based longitudinal study conducted from 2016 to 2019. A total of 2749 primary school children participated in the baseline study. Longitudinal anthropometric data were obtained from annual health check. BW (kg) was categorized into 4 groups [(< 3.0, 3.0-3.5, 3.5-4.0 and ≥ 4.0 (macrosomia)]. Normal weight, OW and OB were defined based on sex-specific and age-specific body mass index (BMI). Central OB were identified using sex-specific waist-to-height ratio (WHtR). Results Around 14.5% and 15.6% out of 1204 children had lower BW (< 3.0 kg) and macrosomia, respectively. The overall rate of general OB and central OB at baseline were 10.4% and 28.3%, respectively. Linear- and J- shaped relationships were observed between BW and BMI z-score, and WHtR, respectively. In the adjusted analysis, higher levels of BW (≥ 3.5kg) were associated with increased odds of general OB in children. Generalised estimating equations was used to determine Conclusion Higher levels of BW (≥ 3.5 kg) were associated with an increased risk of general OB in children, but not central OB. The results can support implication to public health specialists for future research in Zhejiang province and improvement of strategies for childhood obesity prevention.