Age-Dependent Changes in Bone Mineral Density and Body Composition in Middle-aged and Elderly Women: Role of Growth Hormone, Insulin-like Growth Factor-I and Insulin-like Growth Factor-binding Protein-3

Abstract

The present study was performed to investigate age-dependent changes in bone mineral density (BMD) and body composition, and the role of growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) in these changes in healthy middleaged and elderly Japanese women. BMD and body composition [bone mineral content (BMC), lean body mass (LBM) and fat] were measured by dual energy X-ray absorptiometry. BMD, BMC and LBM declined with aging, while fat mass did not. Plasma IGF- I and IGFBP-3 levels also declined with aging. Urinary GH, plasma IGF-I and IGFBP-3 levels were positively correlated with BMD and BMC, even when BMD was adjusted for age and body size. The plasma IGF-I level was positively correlated with LBM. GH and IGFBP-3 levels also showed the tendency to be correlated with LBM. The urinary GH level was negatively correlated with fat mass, whereas plasma IGF-I and IGFBP-3 levels were positively correlated with fat mass. The GH-IGF-I-IGFBP-3 axis positively regulates bone and muscle mass, while GH and IGF-I-IGFBP-3 negatively and positively regulate fat mass, respectively.