Heroin and methadone users who've ever been diagnosed with AIDS are at dramatically higher risk of bone loss as they get older, according to a study published in the September 24 issue of AIDS.

Potent combination antiretroviral (ARV) therapy has significantly cut the death rate and led to longer life spans in people with HIV. This means that people are now living into older age, when additional health problems typically strike. In fact, experts project that by 2015 more than half of all people with HIV in the United States will be older than 50.

A growing concern is bone mineral loss—called osteopenia when it is mild and osteoporosis when it is more severe. Numerous studies have found higher rates of bone mineral loss among people with HIV than their HIV-negative counterparts. This is particularly true of HIV-positive men.

A further risk factor for decreased bone mineral density (BMD) is use of opiates, including heroin and methadone. Both drugs have been associated with osteopenia and osteoporosis. Since a significant number of people with HIV are current or former drug users, Anjali Sharma, MD, MS, and her colleagues from the State University of New York Downstate Medical Center in Brooklyn set out to measure bone health within this population.

Sharma's team enrolled 389 men in the Bronx, New York, ages 49 and older who were HIV positive or at risk for infection. In total, 230 were HIV positive, and 159 were HIV negative. The men's average age was 56, and most were of average height and weight. More than half of the HIV-positive men had been positive for at least 10 years, and 77 percent of them reported using protease inhibitors. More than half were African American, roughly one quarter were Latino, and the remainder were white or another race. The median CD4 count among the HIV-positive men was 398, and 42 percent had a history of an AIDS diagnosis.

All of the men underwent extensive interviews to determine their behavioral and medical histories. Each of them also underwent dual energy X-ray absorptiometry (DEXA) scans to measure their bone health in the thigh, hip and lower back, both at the time they entered the study and roughly three years later.

Risk factors associated with diminished BMD were common: 88 percent had a history of cocaine use, almost all had a history of smoking (64 percent were current smokers), 47 percent had evidence of alcoholism, and 47 percent had low serum testosterone.

At time of first DEXA, 46 percent of the men overall had normal BMD, while 42 percent had osteopenia, and 12 percent had osteoporosis. Of the men who initially had a normal BMD, 14 percent progressed to osteopenia, and 86 percent continued to have healthy bones. The risk for developing osteopenia among this group was nearly three times higher in the HIV-positive men. Of those who were initially diagnosed with osteopenia, roughly 12 percent progressed to osteoporosis. The rate of progression here was the same for HIV-positive men as for HIV-negative men.

Most of the typical factors for reduced BMD were associated with bone loss in this study, including, age, race, use of corticosteroids or testosterone, and hepatitis C virus (HCV) infection.

Sharma's team, however, found a powerful interaction between use of heroin and a history of an AIDS diagnosis, such that the people with the greatest bone loss were heroin users who'd ever received an AIDS diagnosis. This held up after adjusting for all other risk factors. HCV status and current methadone use were also highly predictive. CD4 count and types of ARVs did not affect BMD.

Oddly, cigarette smoking was not significantly associated with bone loss. However, the authors comment that “the lack of an independent association of BMD loss with cigarette smoking might be due in part to the fact that nearly 90 percent of participants in the cohort were current or former smokers.”

“Taken together, these data suggest that HIV-infected opioid-using men may be at particular risk of bone loss as they age, as a result of comorbid disease such as hepatitis C infection, opioid substitution treatment with methadone, ongoing heroin use, progression to AIDS, or a combination of these factors,” the authors concluded.

“An improved understanding of factors associated with ongoing bone loss and fracture risk is needed,” they continued, “to help guide thresholds for assessment of BMD and for osteopenia treatment in HIV-infected persons and opioid users.”