Association between serum osteocalcin and insulin resistance in postmenopausal, but not premenopausal, women in Korea

Abstract

Menopause is known to compound cardiometabolic disease risk factors, and a deeper understanding of the mechanism of this effect is needed. Recently, the osteoblast-derived protein osteocalcin was found to function as a regulator of glucose and fat metabolism. However, there is a lack of studies comparing the extent of association between osteocalcin and glucose metabolism in postmenopausal versus premenopausal women. To examine the relationship between serum osteocalcin and glucose metabolism in premenopausal versus postmenopausal women, we identified well-balanced pairs of premenopausal and postmenopausal women matched on propensity score. The interactions between serum osteocalcin levels and menopause status on fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) and the associations of these parameters with serum osteocalcin levels in premenopausal and postmenopausal women were statistically analyzed. Among the 61 matched pairs of premenopausal and postmenopausal women, significant interactions of menopause status and serum osteocalcin levels were observed for fasting insulin (P = 0.031) and HOMA-IR (P = 0.019). Furthermore, after logarithmical transformation for each variable, significant relationships between serum osteocalcin levels and fasting insulin (r = -0.307, P = 0.016) and HOMA-IR (r = -0.298, P = 0.019) were found in postmenopausal women, but no significant correlation was seen in premenopausal women (r = 0.002, P = 0.989 and r = 0.062, P = 0.633, respectively). Our study shows that the association between serum osteocalcin and insulin resistance varies according to menopause status, and that serum osteocalcin is associated with insulin resistance in postmenopausal women but not in premenopausal women. As postmenopausal women have a higher prevalence of obesity and other cardiac risk factors, the potential endocrine actions of osteocalcin may serve as a marker of metabolism in menopause status. Further studies are needed to define the precise nature of the relationship between osteocalcin and insulin resistance in postmenopausal women.