The effect of high birth weight on overweight and obesity in childhood and adolescence. A cohort study in China

OBJECTIVE: To determine the association of high birth weight (HBW) with the risk of obesity in childhood and adolescence. We also aimed to explore the interactions of HBW with physical activity and dietary habits.

METHODS: In a birth cohort born in 1993, 1994, and 1995 in Wuxi, China, subjects with a birth weight (BW) of >/=4000 g were selected as the exposed group. For each exposed subject, one non-exposed subject with a BW of 2500-3999 g, matched by year of birth, gender, and type of institute at birth was chosen. Two follow-ups were performed from October 2005 to February 2007 and July 2010 to December 2011.

RESULTS: A total of 1108 exposed and 1128 non-exposed subjects were included. Overweight/obesity rates were significantly higher in the exposed group (16.2% in childhood and 14.2% in adolescence) than those in the non-exposed group (12.1% in childhood and 8.2% in adolescence). There was no significant interaction between BW and the growth period (F=2.10, p=0.147). The relative excess risk due to interaction (RERI) of HBW with physical activity was -0.20 (95% CI=-2.85-2.45), and the RERI of HBW with dietary habits was 1.19 (95% CI=0.14-2.23).

CONCLUSION: Infants with HBW are at increased risk of childhood and adolescent overweight/obesity, and this relationship is not influenced by the growth period. There is an additive interaction between HBW and dietary habits.