Interaction of body weight and ethnicity on risk of gestational diabetes mellitus

Background: The James Bay Cree of Canada have one of the highest recorded rates of gestational diabetes mellitus (GDM) among aboriginal people worldwide; the reasons for this elevated risk remain to be documented. Objective: Our objective was to compare predictors and risk of GDM between the James Bay Cree and non-Native Canadians. Design: Risk for GDM was compared between Cree and non-Native women by l) adjusting statistically for differences in age, parity, pregravid weight, and smoking status (n = 402 Cree, 7718 non-Natives), and 2) matching Cree women with non-Native women for age and pregravid weight (n = 394 Cree, 788 non-Natives). Dietary and physical activity information was available for a subset of Cree women (n = 152). Results: Age and pregravid weight were independent predictors of GDM in both Cree and non-Native women. After these predictors were controlled for, normal-weight (≤77 kg) Cree women were not at increased risk of GDM (OR: 1.42; 95% CI: 0.67, 2.71) but overweight Cree women had a higher risk than did overweight non-Native women (OR: 2.25; 95% CI: 1.32, 3.80). Conclusions: Overweight Cree women are at increased risk of GDM. Given the high prevalence of pregravid overweight among the Cree, the burden of GDM is higher than among non-Native Canadians.