Exploring Strategies for Attenuating Changes in Bone Mineral Density in Men who have Sex with Men Using Tenofovir/Emtricitabine Pre-exposure Prophylaxis
Bibliographic record
Abstract
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.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".