French researchers have found rates of serious bone weakness in HIV-positive patients, particularly HIV-positive men, to be many times higher than in the general population’s, according to a new study published in the January 30 issue of AIDS.

Charles Casanave, MD, of the Fédération de Maladies Infectieuses et Tropicales in Bordeaux, France, and his colleagues enrolled 492 patients from a larger group of HIV-positive people being followed in southwestern France known as the Aquitaine Cohort. Seventy-three percent of the patients were men, 70 percent were active smokers—a risk factor for poor bone health—and less than 8 percent took supplemental calcium. The average age was 43 years for men and 41 years for women.

Body mass index (BMI), which is calculated based on a person’s height and weight, was available for 482 participants, 24 percent of whom had a BMI of less than 20, which is considered low and is a further risk factor for poor bone health. The vast majority of participants, 93 percent, were on combination antiretroviral therapy.

In order to diagnose osteopenia—a moderate reduction in bone mineral density—and osteoporosis—a more severe reduction in bone mineral density that can increase the risk of a serious fracture—Casanave’s team conducted dual energy X-ray absorptiometry (DEXA) scans on the participants’ spines and femurs, the large leg bone that links to the hip.

Fifty-five percent of the men in the study and 51 percent of the women were diagnosed with osteopenia. Thirty-four percent of the men and 8 percent of the women were diagnosed with the more serious osteoporosis. Other studies of bone health in people living with HIV have found rates of osteoporosis of 15 percent, which is almost four times higher than in similar people who are HIV negative.

Factors associated with osteopenia and osteoporosis in men included having acquired HIV through sex with other men and having an undetectable viral load. Men whose CD4 counts had ever been particularly low, known as the CD4 nadir, were also at greatest risk of osteopenia. The authors theorized that rates may have been higher in gay men because of higher rates of substance use in this community and higher rates of infection with herpes virus type 8 and Kaposis sarcoma, which can affect bone health.

In women, older age and low CD4 nadir were associated with a greater risk of having osteopenia or osteoporosis.

When measured directly, antiretroviral therapy was not associated with an increased risk for either disorder. Casanave’s team reasoned, however, that an undetectable viral load and low CD4 nadir both occur most commonly in people who’ve been on antiretroviral therapy and thus may point to some contribution of the meds on people’s bone health.

Casanave’s team also explains that the extremely high rates of osteoporosis found among the men in the study may be at least partially explained by the fact that the DEXA scans of the men had to be compared to samples from men in the United States, who on average consume more calcium than French men. The team is calling for more research to accurately determine how prevalent bone problems are in people living with HIV and what risk factors most contribute to those problems.