Association between low C-peptide and fragility fractures in postmenopausal women without diabetes

Purpose : C-peptide has been shown to exert several, previously unknown, biological effects. A recent cross-sectional study demonstrated an association between low C-peptide serum levels and low lumbar bone density of postmenopausal women not affected by diabetes. To date, very little research attention has been directed toward the association between C-peptide and osteoporotic fractures. To contribute toward filling this gap, we investigated the association between C-peptide and fractures in postmenopausal women. Methods: A cohort of 133 non-diabetic postmenopausal women with and without a history of fractures was evaluated in this cross-sectional investigation. Standardized interviews were performed to gather information on the patients’ fracture history. All of the participants underwent a bone mineral density assessment by DXA, radiographs, and a serum C-peptide measurement. Results: Thirty-four women presented fractures. Bivariate analysis revealed an inverse correlation between C-peptide and fractures (r= -0.27, p=0.002). A significant difference in mean C-peptide levels was also found between women with vs. without fractures (p=0.01, adjusted for age, BMI and glucose). Logistic regression analysis showed that C-peptide levels, femoral and vertebral BMD were all negatively associated with fracture status.(B=-1.097, ES=0.401, p=0.006, 95%CI 0.15-0.73; B= -15.6, SE=4.17, p<0.001, CI 0.001-0.002; B=-24.8, SE =5.23, p<0.001,CI 0001-0.002; respectively). Conclusions: This study confirms an inverse association between serum C-peptide levels and a history of fractures in postmenopausal women without diabetes. These results suggest that C-peptidemay exert an effect on bone mineral density. However, further large-scale studies are needed in order to corroborate this finding and investigate the potential underlying mechanisms involved