High birth weight and overweight or obesity among Chinese children 3-6 years old

Objective: To investigate the association between different levels of birth weight and the risk of overweight and obesity in children aged 3-6 years. Methods: A retrospective longitudinal study of 15,852 children aged 3-6 years in Tianjin, China. Body weight and height, and other factors (age, gestational age, past and current health status, father's and mother's education, occupation and health status, family income, and sex) were obtained using standardized methods. Results: After adjustment for the above other factors, Chinese children who were born with a birth weight below 2500 g are less likely to become overweight or obese (body mass index more than the 85th percentiles for age and gender specific distribution using the World Health Organization growth reference) during childhood (odd ratio [OR] 0.84, 95% confidence interval [CI] 0.47-1.52) when compared to the reference group (2500-2999 g). However, the odds ratios of becoming overweight or obese during childhood increase significantly when birth weights are 3000-3499 g (OR 1.58, 95% CI 1.33-1.88), 3500-3999 g (OR 2.09, 95% CI 1.76-2.49), and more than 4000 g (OR 3.14, 95% CI 2.60-3.79). Conclusions: High levels of birth weight, defined as birth weight > 3000 g, were a stronger predictor for overweight and obesity among the Chinese children aged 3-6 years.