BACKGROUND/AIM: Insulin-like growth factor (IGF) axis hormones are associated with multiple chronic diseases. Reports of the relationship between adiposity and IGF-axis hormones vary widely. This study hypothesized that physical activity levels modify the association of IGF axis hormones with adiposity. PATIENTS AND METHODS: Data from NHANES III were used to assess whether associations of adiposity, namely waist-to-hip ratio (WHR), with IGF axis hormones varied according to physical activity. RESULTS: Among those in the lowest physical activity quintile, WHR had a substantive inverse association: bioavailable IGF-I was 16% lower among those in the highest versus the lowest WHR quintiles among the least active subjects (p<0.001). By comparison, among those in the highest physical activity quintile, IGF-I did not vary by WHR. CONCLUSION: The association of bioavailable IGF-1 with central adiposity differs among active versus inactive adults in the U.S.A. This has relevance to understanding previously reported benefits of physical activity among overweight individuals.
BACKGROUND/AIM: Insulin-like growth factor (IGF) axis hormones are associated with multiple chronic diseases. Reports of the relationship between adiposity and IGF-axis hormones vary widely. This study hypothesized that physical activity levels modify the association of IGF axis hormones with adiposity. PATIENTS AND METHODS: Data from NHANES III were used to assess whether associations of adiposity, namely waist-to-hip ratio (WHR), with IGF axis hormones varied according to physical activity. RESULTS: Among those in the lowest physical activity quintile, WHR had a substantive inverse association: bioavailable IGF-I was 16% lower among those in the highest versus the lowest WHR quintiles among the least active subjects (p<0.001). By comparison, among those in the highest physical activity quintile, IGF-I did not vary by WHR. CONCLUSION: The association of bioavailable IGF-1 with central adiposity differs among active versus inactive adults in the U.S.A. This has relevance to understanding previously reported benefits of physical activity among overweight individuals.