Lean mass is the strongest predictor of bone mineral content in type-2 diabetes and normal individuals: an eastern India perspective

BACKGROUND Impact of body fat distribution on bone mineral content (BMC) and density (BMD) at different sites has not been studied in type-2 diabetes (T2DM). This study aimed to compare BMC and BMD in normal (BMI < 25 kg/m(2)) and increased BMI (BMI ≥ 25 kg/m(2)) T2DM patients with age and BMI matched normal controls, and evaluate the impact of lean mass and body fat distribution parameters on them. METHODS Seventy-six T2DM patients and 56 normal controls underwent anthropometric assessment, blood sampling and estimation of BMC, BMD, body fat and lean mass distribution by dual energy X-ray absorptiometry (DXA). RESULTS Increased BMI individuals (n = 63) had significantly higher BMD, BMC, fat mass and significantly lower 25-hydroxy-vitamin-D (25OHD), as compared to normal BMI individuals (n = 69). Lean mass had stronger positive correlation with BMC and BMD, compared to fat mass. BMI, sagittal abdominal diameter (SAD) and Android/Gynoid (A/G) ratio had positive correlation with BMC and BMD. Percent body fat had negative correlation with BMC and BMD. T2DM patients had higher central obesity (A/G ratio). WC was the best predictor of A/G ratio. Regression analysis revealed lean mass to be the strongest predictor of BMC after adjusting for age, sex, BMI and 25OHD, in normal individuals and patients with diabetes, followed by fat mass. BMD right femur, BMC, lean mass and A/G ratios were significantly higher in males (n = 74). Fat mass and percent body fat were significantly higher in females (n = 58). Fat mass was the best predictor of BMC in males where as lean mass was the best predictor of BMC in females. CONCLUSION Increased BMI and T2DM are associated with increased BMC and BMD at different sites, with lean mass having the strongest impact on BMC in normal individuals and patients with diabetes. Males have higher BMC and BMD as compared to females, likely due to a greater lean mass, A/G ratio, along with lesser fat mass and percent body fat.