Bone metabolism and the 10-year probability of hip fracture and a major osteoporotic fracture using the country-specific FRAX algorithm in men over 50 years of age with type 2 diabetes mellitus: a case-control study

The aim of the study was to evaluate the 10-year probability of hip fracture and a major osteoporotic fracture using the FRAX algorithm, vitamin D status, bone mineral density (BMD), and biochemical markers of bone turnover in men over 50 years of age with type 2 diabetes mellitus (T2DM). We estimated FRAX-predicted 10-year fracture probability, levels of 25-hydroxyvitamin D (25-OH-D), markers of bone turnover, and bone mineral density at the L1-L4 (lumbar spine (LS)) and femur neck (FN) in 68 men with T2DM and compared these with an age-matched group (n = 68). The mean (range) age of the T2DM group was 61.4 (51-78) years. The prevalence of hypovitaminosis D (25-OH-D < 75 nmol/L) was 59 %. The mean (range) FRAX hip fracture and FRAX major osteoporotic fracture was 0.7 (0-2.8) and 3.2 (0-8.5) %, respectively. BMD at the FN (0.974 vs. 0.915 g/cm(2), p = 0.008) and LS (1.221 vs. 1.068 g/cm(2), p < 0.001) was significantly higher in the T2DM cohort as compared to the healthy age-matched males. 25-OH-vitamin D (67.7 vs.79.8 nmol/L, p < 0.001), crosslaps (0.19 vs. 0.24 mu g/L, p = 0.004), and osteocalcin (13.3 vs. 15.7 mu g/L, p = 0.004) were significantly lower in the T2DM group. There was no difference in FRAX-related fracture probability between the two groups. Acknowledging the limitations of our study size, we suggest that the increased BMD in T2DM and the noninclusion of T2DM as a secondary risk factor in the FRAX algorithm may be probable explanations for the discordance between literature-observed and FRAX-related fracture probabilities.