Association of Insulin Resistance with Bone Mineral Density and Fracture Risk in Non-Diabetic Postmenopausal Women

Abstract There is conflicting literature evidence regarding the independent effects of insulin resistance and concomitant hyperinsulinemia on bone mineral density. In addition, it is still under debate whether the net effect is favorable or unfavorable for the fracture risk. Therefore, we conducted a cross-sectional study. Aim To assess the correlation between bone mineral density and fracture risk with insulin resistance and circulating insulin levels in non-diabetic postmenopausal women. Materials and methods The study analyzed 84 women. The mean age of the participants was 60.54 ± 7.07 years, and the mean postmenopausal period was 11.45 ± 6.62 years. A standard oral glucose tolerance test was performed with measurement of blood glucose and insulin levels at 0 and 120 min. Dual-energy X-ray absorptiometry was used to determine bone mineral density at lumbar spine and proximal femur. Fracture risk was calculated using the Fracture Risk Assessment Tool. Results We found that in non-diabetic postmenopausal women lower basal insulin levels (fasting insulin) were associated with a higher 10-year risk of major osteoporotic fracture when insulin sensitivity was preserved (HOMA-IR index < 2). Fasting insulin levels under 6.15 μIU/ml were considered high-risk regarding the fracture risk. On the other hand, higher stimulated insulin levels at 120 min (post-load insulin) were associated with a higher 10-year risk of major osteoporotic fracture at HOMA-IR index greater than 2. Stimulated insulin levels above 39.7 μIU/ml were considered high-risk regarding the fracture risk. Conclusion Our results revealed a negative relationship between stimulated insulin levels at HOMA-IR index above 2 and bone integrity in postmenopausal age. On the other hand, higher basal insulin levels at HOMA-IR index lower than 2 were associated with better parameters of postmenopausal bone health.