Predictors of overweight during childhood in offspring of parents with type 1 diabetes.

OBJECTIVE

To study which perinatal factors affect the risk of childhood overweight in offspring with a first-degree relative (FDR) with type 1 diabetes and to determine whether maternal diabetes is an independent contributor to overweight risk.

RESEARCH DESIGN AND

METHODS

Data on a child's weight and height were collected at age 2, 5, and 8 years from 1,214 children participating in the prospective BABYDIAB study. All children had an FDR with type 1 diabetes, including 783 whose mothers had type 1 diabetes. Overweight was defined as BMI percentile >or=90. Data on birth size, breast-feeding, maternal age, and smoking during pregnancy were collected by questionnaires. Risk estimates were calculated by logistic regression analyses.

RESULTS

Breastfeeding duration and birth size both contributed significantly to overweight risk at all age intervals. Full breast-feeding >4 months or any breast-feeding >6 months reduced risk of overweight (aged 8 years: odds ratio 0.3 [95% CI 0.2-0.7], P = 0.004; and 0.3 [0.1-0.6], P = 0.001). Large-for-gestational-age status increased risk of overweight (aged 8 years: 2.4 [1.4-4.3], P = 0.002). Importantly, no evidence was found for an independent contribution of maternal type 1 diabetes to childhood overweight.

CONCLUSIONS

Our findings indicate that maternal type 1 diabetes is not an independent risk factor for overweight during childhood in offspring of type 1 diabetic mothers but that factors associated with maternal type 1 diabetes, such as short breast-feeding duration and high birth size, predispose children to overweight during childhood.