Change in circulating undercarboxylated osteocalcin (ucOCN) is associated with fat accumulation in HIV-seropositive women.

Background Bone mineral density (BMD) loss and fat accumulation are common in people living with HIV (PLWH). The bone-derived hormone, undercarboxylated osteocalcin (ucOCN) regulates fat metabolism. We investigated the relationship between ucOCN change and body fat change among perimenopausal/postmenopausal HIV-seronegative and HIV-seropositive women on long-term antiretrovirals. Methods Perimenopausal and postmenopausal women enrolled in the Women's Interagency HIV Study (WIHS) MSK sub-study underwent trunk and total fat assessment via dual x-ray absorptiometry (DXA) at study enrollment (index visit) and again two years later. Circulating ucOCN and carboxylated osteocalcin (cOCN) were also measured at the index and two-year visits. The correlation between the two-year change in ucOCN and cOCN and change in trunk and total fat was assessed as a function of HIV-serostatus using linear regression modeling. Multivariate linear regression assessed the association between ucOCN and cOCN change and total and trunk fat change after adjusting for sociodemographic variables. Linear regression models restricted to HIV-seropositive women were performed to examine the contributions of HIV specific factors (index CD4 count, viral load, and cART use) on the associations. Results Increased ucOCN over the two-year follow-up was associated with less trunk and total fat accumulation in models adjusting for HIV-serostatus and participants sociodemographics, while there was no association with cOCN and the fat parameters. None of the HIV-specific factors evaluated influenced the association between ucOCN and fat parameters. Conclusion The current study suggests that increases in ucOCN are associated with decreased fat accumulation in HIV-seronegative and HIV-seropositive postmenopausal women on long-term antiretroviral therapy.