Viral Hepatitis Coinfection Is Linked to Bone Loss in HIV Positive Women but Not Men

By Liz Highleyman

Bone loss (osteopenia or the more severe osteoporosis) is common among people with HIV. To date, it is not fully understood whether this is due to HIV infection itself, antiretroviral drugs such as tenofovir (Viread), the normal aging process as HIV positive people survive longer, or some combination of these and other factors.

Hepatitis C virus (HCV) has been linked to bone loss in some studies; less in known about the effect of hepatitis B virus (HBV) on bone health. Viral hepatitis coinfection may be one of the multiple factors contributing to reduced bone mineral density (BMD) in HIV positive individuals, according to a presentation at the recent 16th Conference on Retroviruses and Opportunistic Infections (CROI 2009) in Montreal.

Vincent Lo Re from the University of Pennsylvania School of Medicine and colleagues aimed to determine whether viral hepatitis is an independent risk factor for low BMD in HIV positive patients.

To this end, they conducted a cross-sectional study that included 1237 HIV patients enrolled in the Modena HIV Metabolic Clinic Cohort in Italy; 625 participants were coinfected with hepatitis B and/or C.

The researchers used dual-energy X-ray absorptiometry (DEXA) to measure bone density of the lumbar spine and femoral neck. Clinical data, HBV and HCV status, and biomarkers of bone metabolism were assessed at the same time.

Results

Mean Z-scores (a standard measure of BMD) were lower among HIV positive women with viral hepatitis compared with HIV monoinfected women at the lumbar spine (difference -0.44; P < 0.001) and femoral neck (difference -0.25; P = 0.009)

However, differences in mean BMD Z-scores were not observed between HIV-viral hepatitis coinfected men and HIV monoinfected men at either the lumbar spine (difference -0.05; P = 0.5) or femoral neck (difference -0.08; P = 0.2).

After adjusting for age, body mass index, duration of HIV infection, use of antiretroviral therapy, physical activity, and tobacco smoking, viral hepatitis was significantly associated with low BMD among women (adjusted OR 2.87) but not among men (adjusted OR 1.19).

Coinfected women had a lower median parathyroid hormone concentration than HIV monoinfected women (56.9 vs 61.7 pg/mL), but similar median 25-hydroxyvitamin D (15.2 vs 16.0 ng/mL) and osteocalcin (4 ng/mL in both groups) levels.

Based on these findings, the investigators concluded, "We identified sex difference in comparison of BMD Z-scores between HIV/viral hepatitis coinfected and HIV-monoinfected patients."

Coinfected women had lower BMD Z-scores at both the lumbar spine and femoral neck compared to women with HIV alone," they continued. "No differences in BM Z-scores between coinfected and monoinfected men."

"The precise mechanisms for association between viral hepatitis and low BMD in HIV-infected women but not men remain unclear," the researchers noted.

In particular, it is not known whether HBV or HCV directly contribute to bone loss in HIV positive women (and if so, why this would not also be the case in men), or whether coinfected women might be more likely to have other risk factors for reduced bone density such as opiate use.

Univ of Pennsylvania School of Med, Philadelphia, PA; Univ of Modena and Reggio Emilia, Italy.

4/17/09

Reference
V Lo Re, G Guaraldi, M Leonard, and others. Viral Hepatitis Co-infection Is Associated with Reduced Bone Mineral Density in HIV-infected Women but Not Men. 16th Conference on Retroviruses and Opportunistic Infections (CROI 2009). Montreal, Canada. February 8-11, 2009. Abstract 820.