Insulin resistance and composite indices of femoral neck strength in Asians: the fourth Korea National Health and Nutrition Examination Survey (KNHANES IV)

Objective Fracture risk in type 2 diabetes mellitus with insulin resistance is increased, despite relatively preserved bone mineral density (BMD). In this study, we investigated the relationship between insulin resistance and composite indices of femoral neck strength in Koreans. Design A population-based, cross-sectional study from the Korea National Health and Nutrition Examination Survey Participants About 1243 men and 1433 women Measurements Insulin resistance was evaluated using the homoeostasis model assessment-estimated insulin resistance (HOMA-IR) index. Femoral neck width and axis length were measured from hip dual-energy X-ray absorptiometry scans and combined with BMD, weight and height to calculate composite indices of femoral neck strength relative to load: compression (CSI), bending (BSI) and impact strength indices (ISI). Results HOMA-IR showed an inverse relationship with CSI, BSI and ISI in both genders before and after adjusting for confounders (P < 0.001-0.029). CSI was more strongly associated with HOMA-IR than BSI and/or ISI in both genders (P < 0.001-0.013). When men were stratified according to HOMA-IR quartiles, all strength indices decreased as the quartile increased, after adjusting for all potential confounders (P for trend < 0.001-0.001), whereas CSI and ISI did in women (P for trend = 0.012 and 0.002, respectively). Fasting insulin levels, but not glucose levels, were negatively associated with all strength indices regardless of confounders (P < 0.001-0.044). Conclusions Insulin resistance is associated with low femoral neck strength, particularly against the compressive load. These findings suggest a better approach to evaluate bone health in insulin-resistant individuals.