Adverse birth outcomes and childhood overweight at age of 3-8 years in a prospective cohort study in Tianjin, China

Objectives: To explore associations between adverse birth outcomes and childhood overweight at 3-8 years of age.

Design: A prospective cohort study.

Setting: Six central urban districts of Tianjin, China.

Participants: 1681 woman-child pairs.

Methods: 1681 woman-child pairs were followed up for 8 years in Tianjin, China. Demographic and clinical information including birth outcomes was collected longitudinally, commencing from first antenatal care visit till postpartum period. Offspring height and weight were measured at 3-8 years of age. High and low weight/length ratios (WLR) at birth were, respectively, defined as ≥90th and ≤10th gestational week and sex-specific percentiles. Overweight for children at 3-5 and 6-8 years of age were, respectively, defined as body mass index (BMI)-for-age and -sex above the 2 z-score and 1 z-score curves of the WHO's child growth standards. Binary logistic regression analysis was used to obtain ORs and 95% CI with a stepwise backward selection method to select independent predictors.

Primary outcomes measures: Childhood overweight.

Results: Of 1681 children, 10.7% (n=179) and 27.8% (n=468) developed overweight at 3-5 and 6-8 years of age, respectively. Large for gestational age (LGA) was associated with increased risk of overweight at 3-5 years of age (aOR: 1.86, 95% CI: 1.27 to 2.72) while high WLR at birth was associated with increased risk of overweight at 6-8 years of age (1.82, 1.41 to 2.34). Low WLR at birth was associated with decreased risk of overweight at 6-8 years of age (0.52, 0.30 to 0.90).

Conclusions: LGA and high WLR at birth predicted childhood overweight at 3-5 and 6-8 years of age, respectively. Low WLR at birth was associated with decreased risk of childhood overweight at 6-8 years of age.