A bone structural basis for fracture risk in diabetes

Area of Science:

• Bone Metabolism and Endocrinology
• Diabetic Complications
• Skeletal Biology

Background:

• Elevated areal bone mineral density (aBMD) in type 2 diabetes mellitus (T2DM) is paradoxically linked to increased fracture risk.
• aBMD may not accurately reflect bone strength, necessitating direct assessment of bone structure and integrity.

Purpose of the Study:

• To directly assess bone structure and strength in individuals with T2DM using quantitative computed tomography (QCT).
• To compare bone geometry, volumetric bone mineral density (vBMD), and estimated bone load to strength ratios between diabetic and non-diabetic individuals.

Main Methods:

• A cross-sectional study comparing 49 individuals with T2DM to age- and sex-matched controls from a random population sample.
• Quantitative computed tomography (QCT) was used to measure bone geometry, vBMD, and strength at the hip, spine, and wrist.
• Hip aBMD and estimated bone load to bone strength ratios were also assessed.

Main Results:

• Diabetic subjects exhibited greater hip aBMD, primarily due to higher trabecular vBMD; cortical vBMD, bone size, and thickness were similar between groups.
• While bone strength measures were generally superior in diabetic individuals, higher body weight led to increased bone loads.
• Consequently, the ratios of bone load to bone strength, indicative of fracture risk, were comparable between diabetic and non-diabetic subjects.

Conclusions:

• Elevated aBMD in T2DM does not translate to improved bone load to strength ratios, offering limited fracture protection.
• The rationale for antiresorptive therapies in T2DM patients with normal bone density is uncertain.
• Further research is required to understand potential diabetes-induced deficits in bone quality.