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

## TL;DR

This study finds that higher birth weight is linked to a greater risk of general obesity in children, but not central obesity, over a four-year period.

## Contribution

The study identifies a J-shaped relationship between birth weight and central obesity in boys and a linear relationship with general obesity.

## Key findings

- Higher birth weight (≥3.5 kg) is associated with increased odds of general obesity in children.
- A J-shaped relationship between birth weight and waist-to-height ratio was observed in boys at 11–13 years.
- Macrosomia (≥4.0 kg) increases the risk of general obesity but not central obesity.

## Abstract

Childhood overweight (OW) and obesity (OB) have become a serious public health concern worldwide. The objective of this study is to investigate the association between the levels of birth weight (BW) and OB and central OB in Chinese primary school children.

A school-based longitudinal study was conducted from 2016 to 2019. Information of children and parents were gained from both children and parents’ questionnaires. Longitudinal anthropometric data were obtained from annual health check. BW (kg) was categorized into 4 groups [<3.0, 3.0–3.4, 3.5–3.9 and ≥ 4.0 (macrosomia)]. Normal weight, OW and OB were defined based on sex-specific and age-specific body mass index (BMI). Central OB was identified using sex-specific waist-to-height ratio (WHtR).

Around 14.5 and 15.6% of 1,204 children had low BW (<3.0 kg) and macrosomia, respectively. The overall rate of OB and central OB at 7–10 years were 10.4 and 28.3%, respectively. Linear-shaped relationships were observed between BW and anthropometric values in both sexes at 7–10 years and 11–13 years. A J-shaped relationship was found between BW and WHtR in boys at 11–13 years. Higher BW status were associated with increased adjusted odds of OB in children (3.5–3.9: OR: 1.5, CI 95%: 1.1–2.0; macrosomia OR: 1.4, CI 95%: 1.0–2.0).

Higher levels of BW (≥ 3.5 kg) were associated with an increased risk of OB in children, but not central OB. The results can support public health specialists for future research and improvement of strategies for childhood obesity prevention.