Birth weight, type 2 diabetes, and insulin resistance in Pima Indian children and young adults

OBJECTIVE - To investigate the mechanisms underlying the association betwee n birth weight and type 2 diabetes in a population-based study of 3,061 Pim a Indians aged 5-29 years. RESEARCH DESIGN AND METHODS - Glucose and insulin concentrations were measu red during a 75-g oral glucose tolerance test, and insulin resistance was e stimated according to the homeostatic model (homeostasis model assessment-i nsulin resistance [HOMA-IR]). Relationships between birth weight, height, w eight, fasting and postload concentrations of glucose and insulin, and HOMA -IR were examined with multiple regression analyses. RESULTS - Birth weight was positively related to current weight and height (P < 0.0001, controlled for age and sex, in each age-group). The 2-h glucos e concentrations showed a U-shaped relationship with birth weight in subjec ts >10 years of age, and this relation was independent of current body size . In 2,272 nondiabetic subjects, after adjustment for weight and height, fa sting and 2-h insulin concentrations and HOMA-IR were negatively correlated with birth weight. CONCLUSIONS - Low-birth-weight Pimas are thinner at ages 5-29 years, yet th ey are more insulin resistant relative to their body size than those of nor mal birth weight. By contrast, those with high birth weight are more obese but less insulin resistant relative to their body size. The insulin resista nce of low-birth-weight Pima Indians may explain their increased risk for t ype 2 diabetes.