Complex interplay among fat, lean tissue, bone mineral density and bone turnover markers in older men

It has been suggested that visceral fat (VF) might be a negative determinant of bone health. The purpose of this cross-sectional study was to assess an interplay among fat, visceral fat (VF), muscle mass, bone mineral density (BMD), and markers of bone turnover in men aged 60-75 years. BMD, lean mass, total fat, VF and appendicular skeletal muscle mass (ASM) were assessed using dual-energy X-ray absorptiometry. Using ELISA assays, we measured serum levels of markers of bone turnover (osteocalcin, parathyroid hormone, human procollagen I N-terminal peptide, and degradation products of C-terminal telopeptide of type I collagen). Mean values of bone markers were within normal range. VF was found not to be associated with BMD and bone turnover markers. ASM was inversely correlated with age, and positively with BMD and lean mass. In linear regression, ASM, VF, total fat, lean mass and body mass index were significant single predictors of BMD. However, after adjustment for age, all these associations were no longer significant. In conclusion, in contrast to some studies on postmenopausal women, in older non-diabetic men with normal lean mass and body fat VF was not associated with BMD and markers of bone formation and resorption.