Type 1 Diabetes Control and Decreased Areal BMD and Bone Resorption

Long-standing, well-controlled type 1 diabetes (T1D) is associated with a decrease in areal bone mineral density (aBMD), low bone turnover, and compromised cortical bone at the ultradistal tibia with decreased estimates of bone strength and stiffness, researchers reported in the Journal of Bone and Mineral Research.

The cross-sectional, case-controlled study sought to assess the effects of T1D of ≥25 years duration on densitometric, microstructural, biochemical, and estimated biomechanical bone properties and to determine whether microangiopathy and diabetic neuropathy had an independent effect on bone microstructure.

Patients with long-standing T1D and nondiabetic controls were enrolled from a university hospital in Basel, Switzerland. Eligible participants had T1D ≥25 years with or without microvascular disease. Dual-energy X-ray absorptiometry and high-resolution peripheral quantitative computed tomography were used to assess biochemical markers of bone turnover.

A total of 59 patients with T1D (mean age, 59.9±9.9 years; 35 male) and 77 non-diabetic control individuals (mean age, 60.9±7.5 years; 47 female) were included. The patients had a mean disease duration of 37.7±9.0 years and a median glycated hemoglobin (HbA_1c) level of 6.8%.

The patients with T1D had significantly lower aBMD at the total hip compared with control individuals (P < .001). In addition, aBMD values at the lumbar spine (P = .04), femoral neck (P = .05), and distal radius (P = .01) were lower in patients with T1D after correction for age, sex, and body mass index. Patients with T1D also had significantly higher FRAX scores for hip (P < .01) and major osteoporotic fractures (P = .02).

Significantly reduced cortical thickness (P < .01) and lower cortical volumetric bone mineral density (vBMD) (P = .03) were observed at the ultradistal tibia in patients with T1D compared with control individuals. Bone strength (P < .01) and bone stiffness (P < .01) were significantly lower in patients with T1D vs control individuals.

Patients who had T1D and diabetic neuropathy (T1DM DN+) had a significant reduction in cortical vBMD (P < .01) compared with control individuals. Participants with T1DM DN+ had a significantly lower estimated bone strength (P = .02) and bone stiffness (P = .01) compared with patients with T1D and without DN. Patients with T1DM DN+ also had a highly significant decrease in bone stiffness (P < .001) and bone strength (P < .001) compared with nondiabetic control individuals.

One of several study limitations is the overall good glycemic control among the participants, which did not allow for further assessment of any exposure-response relationship of glycemic control on microstructural changes independent of microvascular disease. Also, the frequency of falls and hypoglycemia were self-reported and may have been underrepresented.

“Further research is warranted to evaluate whether these structural changes and specifically the presence of diabetic neuropathy can explain the increased fracture risk in type 1 diabetes,” stated the researchers.

Reference

Sewing L, Potasso L, Bauman S, et al. Bone microarchitecture and strength in long-standing type 1 diabetes. J Bone Miner Res. Published online January 29, 2022. doi: 10.1002/jbmr.4517