Background/objectives: The association between high birth weight and obesity is well known, but few studies have assessed the relationship across the full range of birth weight or in different gestational groups. We aimed to investigate the relationship between the full range of birth weight and childhood weight status stratified by gestational age.
Subjects/methods: A national survey of 65 347 children aged 6-18 years was conducted in China, 2013. Weight and height were objectively measured. Multivariable regression models were used to study the associations.
Results: The prevalence of childhood underweight in the low, normal, and high birth weight groups was 10.39%, 6.87%, and 4.06%, respectively. Positive associations between birth weight (kg) and body mass index (BMI)/BMI z-scores were observed in the term, post-term, and overall groups, and this association was attenuated with age. Overall, low birth weight contributed to underweight [odds ratio (OR) 1.60, 95% confidence interval (CI) 1.23-2.10], but not to overweight/obesity. High birth weight was associated with overweight (OR 1.19, 95% CI 1.06-1.34) and obesity (OR 1.51, 95% CI 1.34-1.70), but reduced childhood underweight (OR 0.57, 95% CI 0.46-0.71) and normal weight. Similar trends were observed in the term, but not in the preterm group. High birth weight was positively related to obesity in the post-term subgroup (OR 2.06, 95% CI 1.03-4.11).
Conclusions: Overall, low birth weight increased the risk of childhood underweight, but did not affect the risk of overweight or obesity. High birth weight increased childhood overweight and obesity, but decreased underweight. Similar trends were observed in the term group.