Greater insulin resistance tied to increased BMD, but not fracture risk
An association exists between greater insulin resistance (IR) and higher bone mineral density (BMD) in nondiabetic older adults, but evidence for an increased fracture risk with greater IR is inconsistent, a recent study has found.
The homeostatic model assessment (HOMA) of IR quartiles had cutoff values of 1.05, 1.54 and 2.33. The fourth HOMA-IR quartile showed 0.104-g/cm2 higher total hip BMD than the first quartile (p<0.001). Adjustment made for body mass index (BMI) attenuated this difference (adjusted mean difference, 0.007 g/cm2; p=0.371).
Unadjusted models showed a lower fracture risk in participants with higher HOMA-IR (third quartile: hazard ratio [HR], 0.86, 95 percent CI, 0.73–1.01; fourth quartile: HR, 0.65, 0.47–0.89, as compared with the first quartile).
However, fracture risk became significantly greater in the third quartile (HR, 1.19, 1.00–1.41) and slightly higher in the fourth quartile (HR, 1.12, 0.87–1.46) compared with the first quartile when adjustments were made for BMD and BMI.
“In contrast to the relationship between type 2 diabetes (T2D) and fracture risk, we did not find consistent evidence that greater IR is associated with increased fracture risk after adjustment for BMI and BMD,” the investigators said.
This study examined the relationship among HOMA-IR, BMD and incident nonspine fractures in 2,398 community-dwelling, nondiabetic older adults (mean age, 74±3 years; 53 percent women; 38 percent black) in the Health, Aging and Body Composition Prospective Cohort Study (median follow-up, 12 years).
“Adults with T2D have higher fracture risk compared with nondiabetics, despite having higher BMD,” the investigators said. “IR has been associated with increased BMD.”