Bone mineral density is not sensitive enough to assess the risk of vertebral fractures in type 2 diabetic women

Although the association between diabetes and osteoporosis has been studied, it remains unclear if the pathogenesis of vertebral fractures in patients with type 2 diabetes would be similar to those without diabetes. One hundred and fifty female diabetic patients without apparent proteinuria as well as 716 women without diabetes (control group) were examined by lateral thoracic and lumbar spine radiographs as well as dual-energy X-ray absorptiometry. Vertebral fractures were found in 26 (17.3%) and 158 (22.1%) subjects in the diabetic and control groups, respectively. Diabetic patients had higher absolute and age-matched (Z score) values of lumbar bone mineral density (L-BMD) than controls despite their significantly higher mean age. By receiver operating characteristic (ROC) analysis, the absolute L-BMD values for detecting vertebral fractures were higher and sensitivity and specificity were lower in diabetic patients than controls (0.816 g/cm(2) vs. 0.716 g/cm(2) and 66.0% vs. 74.8%, respectively). Logistic regression analysis adjusted for age, body weight, and height also showed that L-BMD was not significantly associated with the presence of vertebral fractures in diabetic patients (odds ratio [OR] = 0.61, 95% confidence interval [CI] 0.34-1.09 per standard deviation increase, P = 0.0954), in contrast to the significant association in controls (OR = 0.23, 95% CI 0.16-0.33, P < 0.0001). These results show that L-BMD is not sensitive enough to assess the risk of vertebral fractures in female diabetic patients and suggest that bone fragility not defined by BMD might be related to the risk of vertebral fractures in them.