Leptin and variables of body adiposity, energy balance, and insulin resistance in a population-based study - The Hoorn Study

OBJECTIVE - Leptin thought to play a key role in the control of body weight . There is a complex interrelationship between leptin and insulin or insuli n resistance, but it is unknown how leptin is regulated. We therefore explo red, in a large population-based study of 2,484 Caucasian subjects aged 50- 74 years, the relationship between leptin and variables of body adiposity, energy balance, and insulin resistance. RESEARCH DESIGN AND METHODS - Leptin was measured by means of a radioimmuno assay. Multiple linear regression analyses were performed with leptin as de pendent variable and age, sex, BMI, waist circumference, daily energy intak e, physical activity, smoking, hypertension, fasting triglyceride concentra tions, HDL cholesterol, fasting plasma glucose, and fasting plasma insulin concentrations as independent variables (determinants). RESULTS - Leptin concentrations were found to be four times higher in women than in men. Effect modification between sex and potential determinants wa s expected, and the analyses were performed separately for women and men. B MI was the strongest determinant of leptin in women and waist circumference the strongest determinant in men. BMI, waist circumference, insulin, and t riglyceride concentrations were independently and significantly (P < 0.05) associated with leptin, while inverse associations were shown for smoking a nd daily energy intake (borderline significance). CONCLUSIONS - This study confirms the relationship between insulin and lept in and, in addition, suggests a relationship between triglyceride concentra tions and leptin independent of sex, BMI, waist circumference, and insulin.