GRAVIDITY, OBESITY, AND NON-INSULIN-DEPENDENT DIABETES AMONG PIMA INDIAN WOMEN

PURPOSE: To evaluate the relationships among gravidity, obesity, and n on-insulin-dependent diabetes mellitus in Pima Indian women. SUBJECTS AND METHODS: Pima Indian women (n = 2,779) participating in a longitud inal epidemiologic study of diabetes were evaluated in both cross-sect ional and longitudinal analyses. RESULTS: The prevalence of non-insuli n-dependent diabetes was higher among women who had never been pregnan t than among those who had been pregnant (age- and obesity-adjusted od ds ratio = 2.0; 95% confidence interval = 1.5 to 2.7). Controlled for age and obesity, nondiabetic women who had never been pregnant had sig nificantly higher fasting plasma glucose concentrations by 2% (P = 0.0 04), higher fasting serum insulin concentrations by 8% (P = 0.09), and higher 2-hour serum insulin concentrations by 10% (P = 0.07) than non diabetic women who had been pregnant. Among 1,025 women observed for a n average of 8 years, those who had not been pregnant by the baseline examination were at significantly higher risk for developing non-insul in-dependent diabetes before the age of 40 years (incidence rate ratio = 1.5; 95% confidence interval = 1.2 to 2.1), but that difference cou ld be accounted for by a higher degree of obesity. CONCLUSIONS: We hyp othesize that Pima Indian women who have a high risk for non-insulin-d ependent diabetes develop obesity and hyperinsulinemia at an early age , and that may be responsible for decreased fertility because of assoc iated changes in sex hormones.