[Show abstract][Hide abstract] ABSTRACT: Patients with diabetes mellitus (DM) are at high risk for fractures. However, the relationship between diabetes and osteoporosis is not yet completely understood. Many factors such as type of diabetes, type of population and co-morbidities may influence the type and severity of bone abnormalities in these patients. The aim of this study was to evaluate which factors may explain the risk of fractures in a homogeneous population of postmenopausal women with type 2 DM. Twenty-one consecutive postmenopausal women with type 2 DM were enrolled. Serum and urinary markers of bone metabolism as well as the biochemical markers of glucose homeostasis and diabetes severity were evaluated. Bone mineral density and prevalence of vertebral fractures were evaluated by using MOC DXA and spine radiography, respectively. The measurement of 25-hydroxyvitamin D serum levels revealed a condition of deficiency in 67% and insufficiency in 28% of patients. Vertebral and femoral neck T-scores were -1.1±1.1 and -0.8±1.0, respectively, while Z-scores were 0.1±1.1 and 0.1±0.9, respectively. Twenty-four % of patients showed ≥1 vertebral fractures. There was a direct correlation between occurrence of fractures and PTH levels (p<0.05), and an inverse correlation between fractures and deficiency of 25-hydroxyvitamin D (p<0.05). In conclusion, although bone mineral density is comparable with that of age-matched normal subjects, patients with type 2 DM have an increased risk of fracture which appears to be associated with vitamin D deficiency and secondary increase of PTH.