Environmental and Familial Contributions to Insulin Levels and Change in Insulin Levels in Middle-aged Women

OBJECTIVE: To examine familial and environmental variables associated with elevated insulin levels and changes in insulin levels in healthy, premenopausal women. METHODS: A population-based sample of 518 women (aged 42 to 50 years) completed baseline assessments of weight, cardiovascular risk factors, exercise behaviors, and glucose and insulin levels (fasting and 2 hours after a glucose load); 495 of the women were reevaluated after 3 years. RESULTS: Plasma insulin levels were related to weight, activity level, race, body fat distribution, and weight gain since age 20 years. Parental history of either diabetes or hypertension was also related to elevated insulin levels, independent of body mass index, with the highest insulin levels occurring in those women with a parental history of both diseases. Increases in plasma insulin levels over the years of follow-up were related to weight gain. CONCLUSIONS: This study suggests that importance of using family history to identify women who may have elevated insulin levels and of intervening to prevent weight gain during middle age.