Sex‐specific associations between insulin resistance and bone parameters in overweight and obese older adults

Abstract

Objectives

To determine sex‐specific associations between insulin resistance and bone parameters measured by peripheral quantitative computed tomography (pQCT) in overweight and obese community‐dwelling older adults.

Study design

Cross‐sectional study of 79 community‐dwelling overweight and obese adults (mean±SD age 62.8±7.9 years; BMI 32.3±6.1 kg/m²; 58% women).

Main outcome measures

pQCT assessed distal radius and tibia trabecular volumetric bone mineral density (vBMD) and proximal radius and tibia cortical vBMD, periosteal circumference, endosteal circumference and stress‐strain index (SSI). The Homeostatic Model Assessment of Insulin Resistance (HOMA‐IR) score was calculated from fasting glucose and insulin values. Lean mass was assessed using dual‐energy X‐ray absorptiometry (DXA). Total minutes of moderate and vigorous physical activity (MVPA) was calculated using the Active Australia Survey.

Results

Men and women in this cohort had no significant differences in fasting glucose and insulin concentrations, HOMA‐IR and diabetes prevalence (all P>0.05). In women, HOMA‐IR was positively correlated with proximal radius periosteal and endosteal circumference (r=0.331; P=0.034 and r=0.325; P=0.038, respectively). These associations became non‐significant in multivariable regression analyses, however, HOMA‐IR was negatively associated with proximal radius cortical vBMD (B=‐4.79; 95% CI ‐8.66, ‐0.92) after adjusting for age, lean mass and MVPA. All associations between HOMA‐IR and bone parameters became non‐significant in a sensitivity analysis excluding individuals with diabetes, or self‐reported use of glucose‐lowering medications. There were no associations between HOMA‐IR and bone parameters in men.

Conclusions

HOMA‐IR was negatively associated with radial cortical vBMD in overweight and obese older women, but not in men. Further studies are needed to clarify sex‐specific associations between insulin resistance and bone health in overweight and obese older adults.

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