Abstract
BACKGROUND: The association between body mass index (BMI) and bone mineral density (BMD) has shown inconsistent results, varying by sex and skeletal site. Despite normal or elevated bone mass, individuals with type 2 diabetes have an increased risk of hip and vertebral fractures. AIM: To assess lumbar spine trabecular volumetric BMD (vBMD) across different BMI categories in individuals with and without diabetes. METHODS: This cross-sectional study included 966 men over 50 years old and 1001 postmenopausal women from the Pinggu Metabolic Disease Study. The vBMD of lumbar vertebrae 2 through 4 was measured using quantitative computed tomography. Total adipose tissue, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and lumbar skeletal muscle area were also quantified. RESULTS: In men with obesity (P = 0.038) and overweight (P = 0.032), vBMD was significantly higher in the diabetes group compared to non-diabetic men. After adjusting for age and sex, no significant saturation effect between BMI and BMD was found in participants with diabetes or in women without diabetes. However, a BMI threshold of 22.33 kg/m² indicated a saturation point for vBMD in non-diabetic men. Independent predictors of vBMD in men included age (r = -0.387, P < 0.001), BMI (r = 0.130, P = 0.004), and VAT (r = -0.145, P = 0.001). For women, significant predictors were age (r = -0.594, P < 0.001), BMI (r = 0.157, P = 0.004), VAT (r = -0.112, P = 0.001), and SAT (r = -0.068, P = 0.035). CONCLUSION: The relationship between BMI and trabecular vBMD differs in individuals with and without diabetes. Overweight and obese men with diabetes exhibit higher vBMD.