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High Rate of Bone Thinning in Healthy Gay Men Without HIV
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XVII International AIDS Conference
August 3-8, 2008
Mexico City
Mark Mascolini
Declining bone mineral density (BMD) may afflict up to two thirds of people with HIV infection [1], but some men who have sex with men (MSM) may run a high risk of bone thinning even if they stay free of HIV [2]. One culprit may be drugs that enhance sexual pleasure, though classic factors could also be at play.
Clinicians and public health officials in San Francisco uncovered these findings while laying groundwork for a study of tenofovir as pre-exposure prophylaxis for HIV in gay men. Because tenofovir may have long-term effects on bone, the investigators recorded pretrial bone density with DEXA scans in 209 study participants, none of them infected with HIV.
Median age stood at 40 years in the study participants, 79% of whom were white, 6% Asian, 5% African American, and 8% Hispanic. Weight averaged 187 pounds. Over the past 3 months, 123 men (59%) drank alcohol once or more weekly, 123 (59%) took a multivitamin, calcium, or vitamin D, 65 (31%) used poppers (amyl nitrites), 25 (12%) used amphetamines, and 117 (56%) used any recreational drug.
Twenty (10%) of these otherwise healthy men had low BMD, defined as a Z score at or below -2.0, at the total hip, total spine, and/or femoral neck. Seventy-nine men (38%) had a Z score at or below -1.0 at one or more of these three sites. Nine men (4%) had osteoporosis as defined by the World Health Organization (T score at or below -2.5).
Popper or amphetamine use was significantly more likely in men with low BMD (P < 0.05), while supplemental vitamins or calcium were significantly more common in men with normal bone density (P < 0.05).
Multivariate analysis factoring in age, body mass index, race or ethnicity, alcohol use, and vitamin or calcium supplementation figured that using poppers inflated the risk of low BMD more than 5 times (adjusted odds ratio 5.4, 95% confidence interval 1.2 to 24.2). Amphetamine use raised the risk almost 6 times (adjusted odds ratio 5.8, 95% confidence interval 1.3 to 26.0).
Further tests in 16 men showed that 2 (12.5%) had vitamin D deficiency and 1 (6.25%) had hypogonadism.
The researchers suggested their findings raise the question of how much bone thinning seen in HIV-infected populations "may pre-date HIV infection." Although these findings are intriguing, the study must be viewed as an early step toward assessing osteopenia risk in HIV-uninfected populations with a high risk of becoming infected. The meta-analysis did not account for several osteopenia risk factors, such as cigarette smoking, family history of osteopenia, sedentary lifestyle, and medications or medical conditions that may predispose people to osteopenia.
References
1. Brown TT, Qaquish RB. Antiretroviral therapy and the prevalence of osteopenia and osteoporosis: a meta-analytic review. AIDS. 2006;20:2165-2174.
2. Liu A, Gvetadze R, Sellmeyer D, et al. Low bone density among a population of healthy HIV-negative MSM screening for a preexposure prophylaxis trial. XVII International AIDS Conference. August 3-8, 2008. Mexico City. Abstract THPE0169.
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