Trabecular bone score and 25-hydroxyvitamin D levels in microvascular complications of type 2 diabetes mellitus

Background and objective: Diabetic microvascular disease (MVD) has been associated with increased bone fragility. The objective was to analyse the relationship between MVD and trabecular microstructure -assessed by the trabecular bone score (TBS)- in type 2 diabetic (T2D) patients. A second aim was to know the relationship between vitamin D and MVD.

Patients and methods: Cross-sectional study, which included men >50 years and postmenopausal women participating in a population-based cohort, diagnosed with T2D. The presence of nephropathy, neuropathy and/or retinopathy was classified as MVD+. Clinical and laboratory variables, TBS, 25(OH)D and BMD by DXA, were evaluated. Bivariate and multivariate analysis were performed.

Results: We evaluated 361 patients (51.1% women), 63.8 (9) years old. Of them, 92 were MVD+ and presented poorer metabolic control, longer duration of T2D, lower TBS [1.235 (.1) vs. 1.287 (.1); p=.007] and lower levels of 25(OH)D [18.3 (7) vs. 21.6 (8) ng/ml; p=.0001). There were no differences between MVD+ and MVD- with regard to BMD or P1NP and β-CTX markers. After adjusting for confounders, including HbA1c and duration of T2D, the TBS value in MVD+ was 1.252 (95% CI 1.230-1.274) vs. 1.281 (95% CI 1.267-1.295) in MVD- (p=.034). MVD was associated with a 25(OH)D level <20 ng ml with an adjusted OR of 1.88 (95% CI 1.06-3.31; p=.028).

Conclusions: The MVD+ patients presented a significantly lower TBS, after adjusting for confounders. Furthermore, multivariable analysis showed a significant relationship between a low 25(OH)D level and a prevalent MVD.