Relationship between body composition and age, menopause and its effects on bone mineral density at segmental regions in Central Southern Chinese postmenopausal elderly women with and without osteoporosis

We aimed at evaluating the relationship between lean mass and fat mass with age, menopausal age (MA) and years since menopause (YSM) and their effects on bone mineral density (BMD) at segmental regions in postmenopausal elderly women with and without osteoporosis. After using a dual-energy X-ray absorptiometry (DXA) methodology to measure body composition and BMD at posteroanterior spine and hip in 244 postmenopausal elderly non-osteoporotic (Non-OP) women (65.5 ± 4.3 years) and 298 postmenopausal elderly osteoporotic (OP) women (67.1 ± 4.4 years), we found that in postmenopausal elderly Non-OP women, there was no correlation between lean mass with age, MA, and YSM, as well as no correlation between fat mass with age (all, p > 0.05); leg fat (LF) mass (r = 0.187; p < 0.01), whole body fat (WF) mass (r = 0.151; p < 0.05), and trunk fat (TRF) mass (r = 0.141; p < 0.05) were positively correlated with MA; LF (r = −0.131; p < 0.05) and WF (r = −0.127; p < 0.05) were negatively associated with YSM; WF and whole body lean (WL) mass were the most important body composition components influencing BMD at the third lumbar spine (L3), total first to fourth lumbar spine (L1–4) and hip, respectively; TRF was the most significant determinant of BMD at both L2 and L4. In postmenopausal elderly OP women, there was no relationship between body composition with MA (p > 0.05); Trunk lean (TRL) mass (r = −0.183; p < 0.05), leg lean (LL) mass (r = −0.136; p < 0.01), and WL mass (r = −0.162; p < 0.01) were negatively correlated with age; TRL mass (r = −0.132; p < 0.05), LL mass (r = −0.152; p < 0.01), WL mass (r = −0.170; p < 0.01) were also negative with YSM; WF was the most important factor influencing BMD at lumbar spine and hip. These data suggest in postmenopausal elderly Non-OP women, fat mass (TRF, LF, and WF) was more related with MA; WF and WL mass were the most important body composition components influencing BMD at L1–4 and hip, respectively; in postmenopausal elderly OP women, body composition was not correlated with MA; lean mass (TRL, LL, and WL) was more age-related negatively; WF mass was the most significant factor affecting BMD at lumbar spine and hip.