# Femora from adults with type 1 or type 2 diabetes have lower bone strength and smaller hip geometry

## TL;DR

People with type 1 or type 2 diabetes have weaker hip bones and smaller hip structures, which may explain their higher risk of hip fractures.

## Contribution

This study shows that diabetes-related hip fracture risk is linked to bone geometry and strength, not just bone density.

## Key findings

- Femoral strength was lower in both T1D and T2D groups compared to controls.
- Diabetic groups had smaller hip geometry, including reduced femoral neck and trochanter cross-sectional areas.
- Skeletal fragility in diabetes is greater than what can be explained by bone density alone.

## Abstract

The increased hip fracture risk in individuals with type 1 (T1D) and type 2 (T2D) diabetes is not explained by areal BMD (aBMD), indicating that diabetes increases fracture risk through mechanisms independent of aBMD. To investigate, we used QCT to compare femoral strength, volumetric BMD (vBMD), and geometry in cadaveric femora from older adults with T1D (n = 23; 13 female) and T2D (n = 21; 11 female) to controls of similar age, sex, and race (n = 19; 11 female). While aBMD and vBMD measures were similar across groups, femoral strength was lower in the diabetic groups compared to controls. Geometric strength, based on external bone shape, was lower in T1D (−15%, p = .001) and T2D (−12%, p = .014) compared to controls. When combining geometry and density, femoral strength was significantly lower in T1D (−19%, p = .044). The strength-to-density ratio was also lower in T1D and T2D (p ≤ .013), indicating greater skeletal fragility in the diabetic groups beyond what is predicted by BMD. Diabetic groups had smaller bone size, including lower femoral neck volume (−8%, p ≤ .030), neck cross-sectional area (CSA) (−8%, p ≤ .030), and trochanter CSA (−7%, p ≤ .010). These findings suggest that lower femoral strength and smaller geometry contribute to elevated fracture risk in diabetes, warranting further study in larger populations.