Fat mass is negatively associated with bone mineral content in Koreans

Although obesity and osteoporosis are important public health problems, the effect of fat mass on bone mass remains controversial. This study demonstrated that fat mass was inversely related to bone mineral content, and abdominal obesity was significantly associated with bone mineral content independent of total fat mass. Obesity and osteoporosis, two disorders of body composition, have become increasingly important public health problems throughout the world. However, the effect of fat mass on bone mass remains controversial. This study investigates the effect of fat mass and regional fat distribution on bone mass within a community-dwelling cohort. A total of 3,042 subjects (1,284 men, 362 premenopausal women, and 1,396 postmenopausal women) were studied. Fat mass, percent fat mass, lean mass, percent lean mass, and bone mineral content (BMC) were measured by dual energy X-ray absorptiometry. Fat mass and percent fat mass decreased significantly across increasing tertiles of BMC in all three subgroups (men, premenopausal and postmenopausal women). In contrast, lean mass and percent lean mass increased significantly across tertiles of BMC in men, and a similar trend was also identified in postmenopausal women. Interestingly, although correlation analysis showed a positive association between fat mass and BMC (p < 0.05), this association became negative after controlling for age and weight (p < 0.05). Finally, in premenopausal and postmenopausal women, subjects with the lowest waist circumference (WC) had the highest BMC in the higher three quartiles of percent fat mass after adjusting for age and weight (p < 0.05), indicating that abdominal obesity is associated with BMC independent of total fat mass. This study demonstrated that fat mass was inversely related to BMC after removing the mechanical loading effect in Korean men and women. Moreover, abdominal obesity as measured by WC was significantly associated with BMC independent of total fat mass.