Type 2 diabetes patients exhibit delayed but coupled bone remodelling, maintaining cortical porosity comparable to healthy controls: A histomorphometric analysis of trans-iliac bone biopsies.

Abstract

Objective: Fracture risk is increased in longstanding type 2 diabetes (T2D). High-resolution peripheral quantitative CT scans have demonstrated higher cortical porosity in T2D complicated by microvascular disease (MVD). We investigated if cortical bone resorption is followed by inadequate bone formation in individuals with T2D complicated by MVD.

Methods: Thirty-five adult men and women with T2D were recruited from outpatient clinics and through public advertisement. All participants had at least one previous measure of c-peptide >700, a negative GAD antibody test, and 13 had known microvascular disease status. Trans iliac crest bone biopsies were collected for histomorphometric analysis. Glucose control was assessed using HbA1c. Additionally, trans iliac bone specimens from 10 individuals without T2D were included as controls.

Results: Following quality assessment, samples from 30 T2D and 10 controls were used for histomorphometric analyses of cortical bone remodelling. The final study population included 23 men and 7 postmenopausal women with a mean age of 65.8 years for the T2D-MVD group (CI95% 61.2-70.3) and 65.2 years in the T2D + MVD group (CI95% 59.6-70.9), and a mean T2D disease duration of 16.9 years. Seventeen had MVD (57 %). The controls included 5 men and 5 women with a mean age of 64.7 years (CI95% 58.5-70.9). The area, diameter, and density of cortical pores were the same in cases with and without MVD, but the pore diameter was lower than controls. While T2D had significantly more eroded-formative pores compared to controls, there were no significant differences in the proportion of eroded and formative pores between the groups. In quiescent pores/osteons, the osteon diameter and wall thickness were larger in T2D groups than controls.

Conclusion: Cortical bone porosity was not increased in individuals with T2D complicated by MVD. However, an enhanced prevalence of eroded-formative pores and increased osteon diameter concur with a slightly prolonged reversal-resorption phase in T2D irrespective of the presence of MVD.