Effect of alendronate and vitamin D3 on fractional calcium absorption in a double-blind, randomized, placebo-controlled trial in postmenopausal osteoporotic women
Bibliographic record
Abstract
Menopause and increasing age are associated with a decrease in calcium absorption that can contribute to the pathogenesis of osteoporosis. We hypothesized that alendronate plus vitamin D(3) (ALN + D) would increase fractional calcium absorption (FCA). In this randomized, double-blind, placebo-controlled multicenter clinical trial, 56 postmenopausal women with 25-hydroxyvitamin D [25(OH)D] concentrations of 25 ng/mL or less and low bone mineral density (BMD) received 5 weekly doses of placebo or alendronate 70 mg plus vitamin D(3) 2800 IU (ALN + D). Calcium intake was stabilized to approximately 1200 mg/d prior to randomization. FCA was determined using a dual-tracer stable-calcium isotope method. FCA and 25(OH)D were similar between treatment groups at baseline (0.31 ± 0.12 ng/mL and 19.8 ± 4.7 ng/mL, respectively). After 1 month of treatment, subjects randomized to ALN + D experienced a significant least squares (LS) mean [95% confidence interval (CI)] increase in FCA [0.070 (0.042, 0.098)], whereas FCA did not change significantly in the placebo group [-0.016 (-0.044, 0.012)]. After ALN + D treatment, patients had higher 25(OH)D levels (LS mean difference 7.3 ng/mL, p < .001). The rise in serum 1,25-dihydroxyvitamin D(3) (p < .02) and parathyroid hormone (p < .001) were greater in the ALN + D group than in placebo-treated patients. ALN + D was associated with an increase in FCA of 0.07. To our knowledge, there is no other trial showing such a marked rise in calcium absorption owing to treatment with a bisphosphonate or owing to a small rise in 25(OH)D. This unique response of ALN + D is important for the treatment of osteoporosis, but the exact mechanism requires further study.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.004 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".