The association between fracture risk and bone mineral density in black postmenopausal HIV-positive women on HAART

Abstract

Background: Osteoporosis affects millions of people, especially postmenopausal women, worldwide. Osteoporosis and associated fractures are also becomming a concern in the HIV-positive population as a result of higher life expectancy and possible fragility fractures due to the advancement in antiretroviral therapy (ART); increased prevalence of low bone mineral density (BMD) as a result of ART-induced bone demineralization as well as increased bone loss due the HIV-infection it self. Urbanisation also places the urban HIV-positive postmenopausal women at risk for the development of low BMD. In South Africa rapid urbanisation is associated with dietary and lifestyle changes that negatively influence BMD. Thus, the effects of long term use of ART in combination with other factors associated with the aging body as well as urbanisation are a concern. Objectives: This study aimed to determine the number of fracture risk factors and the association with BMD in black postmenopausal HIV-positive women on highly active antiretroviral therapy (HAART). Methods: This study was a cross-sectional analysis and baseline data from 120 HIV-positive black post-menopausal women in a prospective cohort study in the North West Province of South Africa was used. Bone mineral density (at the spine, left femoral neck and total body) was measured by dual X-ray absorptiometry (DXA). The number of fracture risk was determined using a checklist. Multivariate linear regression models were applied to assess associations of fracture risk score with site specific BMDs, adjusting for age, calcium intake, serum vitamin D, duration of HIV infection, duration of HAART and physical activity. Results: All participants had the age (>40 years) and female sex risk factors, with 39.2% having only two and 37.5% having three risk factors. The maximum number of risk factors was five. Age and underweight were the only individual risk factors significantly associated with BMD. In adjusted models, only age was significantly associated with BMD, but fracture risk was included in the final model for spine BMD and left femoral neck BMD. No significant association between fracture risk score and BMD was found. Conclusions: A maximum of five fracture risk factors were found, but fracture risk score was not significantly associated with BMD in this group of HIV-positive women.