title: Bone mineral density in HIV-negative men participating in a tenofovir pre-exposure prophylaxis randomized clinical trial in San Francisco.
abstract: BACKGROUND
  Pre-exposure prophylaxis (PrEP) trials are evaluating regimens containing tenofovir-disoproxil fumarate (TDF) for HIV prevention. We determined the baseline prevalence of low bone mineral density (BMD) and the effect of TDF on BMD in men who have sex with men (MSM) in a PrEP trial in San Francisco.
  
  
  RESULTS
  We evaluated 1) the prevalence of low BMD using Dual Energy X-ray Absorptiometry (DEXA) in a baseline cohort of 210 HIV-uninfected MSM who screened for a randomized clinical trial of daily TDF vs. placebo, and 2) the effects of TDF on BMD in a longitudinal cohort of 184 enrolled men. Half began study drug after a 9-month delay to evaluate changes in risk behavior associated with pill-use. At baseline, 20 participants (10%) had low BMD (Z score≤-2.0 at the L2-L4 spine, total hip, or femoral neck). Low BMD was associated with amphetamine (OR = 5.86, 95% CI 1.70-20.20) and inhalant (OR = 4.57, 95% CI 1.32-15.81) use; men taking multivitamins, calcium, or vitamin D were less likely to have low BMD at baseline (OR = 0.26, 95% CI 0.10-0.71). In the longitudinal analysis, there was a 1.1% net decrease in mean BMD in the TDF vs. the pre-treatment/placebo group at the femoral neck (95% CI 0.4-1.9%), 0.8% net decline at the total hip (95% CI 0.3-1.3%), and 0.7% at the L2-L4 spine (95% CI -0.1-1.5%). At 24 months, 13% vs. 6% of participants experienced >5% BMD loss at the femoral neck in the TDF vs. placebo groups (p = 0.13).
  
  
  CONCLUSIONS
  Ten percent of HIV-negative MSM had low BMD at baseline. TDF use resulted in a small but statistically significant decline in BMD at the total hip and femoral neck. Larger studies with longer follow-up are needed to determine the trajectory of BMD changes and any association with clinical fractures.
  
  
  BACKGROUND
  ClinicalTrials.gov: NCT00131677.
authors: San Francisco Department of Public Health, San Francisco, California, United States of America. albert.liu@sfdph.org
authors: Albert Y
authors: AY
authors: Liu
authors: Eric
authors: E
authors: Vittinghoff
authors: Deborah E
authors: DE
authors: Sellmeyer
authors: Risha
authors: R
authors: Irvin
authors: Kathleen
authors: K
authors: Mulligan
authors: Kenneth
authors: K
authors: Mayer
authors: Melanie
authors: M
authors: Thompson
authors: Robert
authors: R
authors: Grant
authors: Sonal
authors: S
authors: Pathak
authors: Brandon
authors: B
authors: O'Hara
authors: Roman
authors: R
authors: Gvetadze
authors: Kata
authors: K
authors: Chillag
authors: Lisa
authors: L
authors: Grohskopf
authors: Susan P
authors: SP
authors: Buchbinder
mesh_terms: D015502:Absorptiometry, Photon; D000225:Adenine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000293:Adolescent; D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology*; D015519:Bone Density / Q000187:drug effects*; D004608:Eligibility Determination; D050723:Fractures, Bone / Q000453:epidemiology / Q000503:physiopathology; D018023:HIV Seronegativity / Q000187:drug effects* / Q000502:physiology*; D018451:Homosexuality, Male; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000494:pharmacology*; D011314:Preventive Health Services / Q000379:methods*; D012495:San Francisco / Q000453:epidemiology; D000068698:Tenofovir; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D000068698:Tenofovir; D000225:Adenine