O17 Evaluation of vitamin D levels in adult patients with type 2 diabetes and its relationship with bone mineral density and the prevalence of vertebral fractures

Abstract

Introduction: Low levels of 25(OH)D are associated with impaired β-cell function, insulin resistance, and increased risk of type 2 diabetes mellitus (T2DM). On the other hand, most studies report an increased risk of hip fracture in T2DM, but the data are contradictory regarding vertebral fractures (VF).

Objectives: Evaluate 25(OH)D levels in adult patients with T2DM and its relationship with glycemic control, severity of T2DM and cardiovascular disease (CVD) risk factors, and to evaluate the bone mineral density of the lumbar spine (LS-BMD) and of the femoral neck (FN-BMD) in conjunction with the prevalence of VF.

Materials and methods: A cross-sectional study was performed and we evaluated 25(OH)D levels and prevalence of morphometric VF. 209 patients with T2DM (T2DM group) and 172 patients without T2DM were evaluated, who were included as control group (CG). The level of 25(OH)D, bone mineral density (BMD) of the lumbar spine (BMD-L) and femoral neck (BMD-FN) were determined. Spine radiographs were obtained to assess the presence of morphometric VF and abdominal aortic calcifications (AAC). Logistic regression analyzes were performed. Differences were considered statistically significant at p < 0.05.

Results: T2DM group presented lower levels of 25(OH)D (19 vs 22 ng/ml) and a higher proportion of patients with deficiency (49.7% vs 35.5%). 25(OH)D was lower among those with low levels of physical activity, arterial hypertension, dyslipidemia, and metabolic syndrome, and it was negatively correlated with BMI, glycemia, and HbA1c. 25(OH)D deficiency correlated with T2DM condition (OR 2.01) and BMI greater than 27.6 kg/m2 (OR 2.4). Patients with T2DM had a higher LS-BMD (1.190 vs 1.010 g/cm2), a higher FN-BMD (0.864 vs 0.776 g/cm2) and a higher prevalence of VF (34.8 vs 11.6%). The women with T2DM and VF were younger than those of the CG with VF (61 vs 71 years). A higher frequency of AAC was not observed among patients with VF and LSBMD did not differ between those with T2DM with or without VF. T2DM was associated with VF with an OR of 3.54.

Conclusion: T2DM patients presents a greater deficiency of 25(OH)D. Furthermore, 25(OH)D levels are lower in patients with poorer glycemic control, CVD risk factors, and microvascular complications. Likewise, there is greater bone fragility expressed from a higher prevalence of VF, which occurs at a younger age and at a higher L-BMD.