Background:  High prevalence of osteopenia and osteoporosis has been described in HIV⁺ patients. A possible association with HAART remains controversial. We conducted a prospective study to identify factors associated with reduced bone mineral density (BMD) among HIV⁺ individuals.

Methods:  Consenting ambulatory HIV⁺ adults were enrolled. All participants completed a detailed questionnaire and a dual-energy X-ray absorptiometry (DEXA) scan of lumbar spine and femoral neck. Full laboratory and HAART-related information were also obtained. Osteopenia and osteoporosis were diagnosed according to the WHO criteria. Logistic regression analysis was performed in both univarite and multivariate setting to investigate factors associated with abnormal BMD.

Results:  From January 2005 to July 2007, 299 patients completed the study:  79% were Caucasian, 89% male, median age was 48 years (IQR 43 to 55). A full 67% of patients had abnormal DEXA scans with osteopenia in 54% and osteoporosis in 13 %. Using an Akaike’s information criterion model selection approach, the multivariate analysis confirms that age, body mass index (BMI), ethnicity, and current CD4 count were risk factors for low BMD. Low physical activity and alcohol intake were also significantly associated with low BMD among men. There was no correlation between abnormal BMD and any metabolic or laboratory parameters evaluated. When ART drugs were explored, tenofovir (TDF) exposure (but not protease inhibitor exposure or total ART exposure) was associated with low BMD. The mechanism behind this association could not be elucidated within this analysis.

Conclusions:  We found a 67% prevalence of abnormal BMD by DEXA scan in an unselected group of HIV⁺ individuals. Risk factors for low BMD included low BMI, older age, low CD4 cell count, alcohol consumption and lower physical activity. An association was also uncovered with longer exposure to TDF; this merits further study.