Journal of AIDS & Clinical Research

Abstract

Jean-Luc Kortenaar, Angela M Cheung, Shabbir Mewa, Esther Waugh, Laurence Rubin and Darrell HS Tan*

Objective: Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) as HIV pre-exposure prophylaxis (PrEP) decreases bone mineral density (BMD). We explored the impact of vitamin D supplementation, dietary calcium intake, and bone loading exercise on BMD during the first 12 months of daily TDF/FTC PrEP.

Methods: All participants from the PREPARATORY-5 pilot demonstration project of gay and bisexual men were eligible for inclusion if they had dual-energy X-ray absorptiometry scans at both baseline and 12 months (n=39). Selfreported vitamin D supplementation was collected prospectively, whereas data on diet and exercise was obtained retrospectively after the trial period, using validated questionnaires. We compared median percent changes in BMD and trabecular bone score (TBS) between those with and without vitamin D supplementation, those with optimal (1000 mg/day) and inadequate (<500 mg/day) dietary calcium intake, and those in the highest versus lowest tertile of contemporaneous bone loading exercise.

Results: Median (interquartile range) participant age was 34 (29, 39) years, 74% were White, and most had some post-secondary education. Overall, median BMD declined significantly from baseline to 12 months at all anatomic sites, changing by -2.14% at the lumbar spine (p<0.01), -1.66% at the femoral neck (p<0.01), and -0.85% at the total hip (p<0.01). Compared to those not using vitamin D, those taking any vitamin D supplementation had a smaller median percent decline in the lumbar spine TBS that was not statistically significant (-1.42% versus -3.99%, p=0.06), and no difference in the lumbar spine BMD (-2.11% versus -2.14%, p=0.40), femoral neck BMD (-1.75% versus -1.17%, p=0.34) and total hip BMD (-0.89% versus - 0.69%, p=0.41). There were no significant differences in BMD or TBS according to dietary calcium intake or bone-loading exercise.

Conclusion: Vitamin D supplementation may have an attenuating effect on PrEP-related deterioration of lumbar spine bone microarchitecture. The relationship between vitamin D supplementation and PrEP-related changes in BMD warrants further investigation.