Modeling the Risk of Decrease in Bone Mineral Density in Men with Type 2 Diabetes

Abstract

Background and aim: Obesity has a modifying effect on bone mineral density (BMD) in femalewith type 2 diabetes mellitus. The risk factors for BMD decrease in men with type 2 diabetes remain to be elucidated. Thisstudy aimed to assess the relationships between the decrease in BMD, obesity and body composition in men with type 2 diabetes. Materials and Methods: We observed 75 men with type 2 diabetes, aged from 50 to 75 years (median 63 years). The BMD and total body composition (TBC)parameters were assessed by dual-energy X-ray absorptiometry. Results: The decrease in BMD was revealed in 32 patients (42.7%). Among them, 28 patients had osteopenia and 4 patients had osteoporosis. These patients, as compared to those with normal BMD, demonstrated lowerfat mass ( $\mathbf{p}=0.03$ ), and a tendency to decrease in lean mass ( $\mathbf{p}=0.06$ ). There were positive correlations between body mass indexand BMD in the proximal femur and forearm. A positive correlation was found between waist circumference and BMD of the proximal femur. BMD of the proximal femur, femoral neck, forearm and lumbar spine demonstrated positive correlationswith fat mass. In the stepwise multivariate linear regression analysis, which included age, duration of diabetes, BMI, waist and hip circumference, as well as TBC parameters as independent variances, the body mass turned out to be the most significant predictor for BMD of femoral neck and proximal femur $(\boldsymbol{\beta}=0.48, \mathbf{R}2=0.24, \mathbf{p}=0.008$ and $\boldsymbol{\beta}=0.55, \mathbf{R}2=0.3, \mathbf{p}=0.002$ respectively). Total fat mass accounted for 18% of the dispersion of the T-criterion of proximal femur ( $\boldsymbol{\beta}=0.30,\quad \mathbf{p}=0.002$ ). For radial bone BMD, the concentration of HbA1c was most important predictor ( $\boldsymbol{\beta}=0.41, \mathbf{R}2=0.24, \mathbf{p}=0.03$ ). Conclusions: The results indicate the modifying effect of obesity and glycemic control on the BMD in men with type 2 diabetes. Since a significant portion of the BMD variability remains inexplicable by these factors, the search for other predictors of osteoporosis in this group of patients is a challenge for future research.