Sixty-nine randomized trials covering 153,902 adults found that calcium and vitamin D supplements, taken alone or together, made little difference to the chance of breaking a bone. For vitamin D alone, the pooled risk ratio for any fracture was 1.00, which is no effect at all. For calcium alone it was 0.91, with a confidence interval that just reaches 1.01.
The systematic review and meta-analysis was led by Olivier Massé, a clinical pharmacist at CIUSSS North Montreal Island, with David Williamson as final author and seven other Canadian colleagues, among them Claudia Mei Mercurio, Sébastien Dupuis and Nicolas Dugré. It appeared in The BMJ in 2026, and its conclusion is blunt: the findings “do not support routine supplementation with calcium, vitamin D, or combined supplementation to prevent fractures or falls.”
Three supplement strategies, three bodies of evidence
The review, published in The BMJ as article e088050, pooled 69 randomized controlled trials involving 153,902 adults and compared calcium, vitamin D or both against placebo or no treatment. It was built on a protocol the same group registered and published in BMJ Open in 2024, which noted that earlier reviews had “generally shown no efficacy” for calcium or vitamin D alone and mixed results for the combination, according to the PubMed record of that protocol.
Per the BMJ Group summary, calcium alone was assessed in 11 trials with 9,067 participants, graded moderate-certainty evidence. Vitamin D alone covered 36 trials and 92,045 participants, and the combination 15 trials and 51,126 participants; both were graded high-certainty. Those three headline comparisons add up to 62 trials and 152,238 people. The summary does not itemise the remaining seven trials and 1,664 participants, so their exact role in the 69-trial total is not spelled out there.
Risk ratios that hug 1.0
The numbers matter more than the adjectives. As tabulated by The ObG Project, the risk ratio for any fracture was 0.91 (95% CI 0.81 to 1.01) for calcium, 1.00 (0.95 to 1.06) for vitamin D and 0.91 (0.84 to 0.99) for the two together. Only the combination has an interval that stays below 1.0, and barely. ScienceAlert’s account of the paper adds that the authors judged even that benefit too small to be clinically meaningful. Hip fractures and falls showed similarly minimal effects. Two of the three intervals include 1.0, meaning the data remain compatible with no effect at all, and the third has an upper bound of 0.99, one hundredth of a point below it. Every estimate in the review therefore sits on or very near the line of no difference, whichever supplement is examined.
The certainty grades change how much weight each row deserves. Moderate certainty for calcium alone means further trials could still shift that estimate; high certainty for vitamin D alone and for the combination means new evidence is unlikely to move them. Vitamin D alone carries the most weight in the whole review: 36 trials, 92,045 participants, close to 60% of the 153,902 total, and a pooled risk ratio of exactly 1.00. A result that large and that flat is hard to explain away as a shortage of data.
A risk ratio of 0.91 is a 9% relative reduction. Because most trial participants never fracture during follow-up, a relative cut of that size translates into a small absolute difference, which is the practical meaning of “barely moved.”
Populations the conclusion leaves out
The authors are explicit about the edges of their finding. According to the release, the conclusions may not apply to people with specific bone disorders or to those already receiving osteoporosis medications, and some analyses rested on relatively small numbers of trials or participants. ScienceAlert reports that few trials enrolled people with severe vitamin D deficiency, so the review cannot say whether supplements help those with documented deficiency or residents of care homes, where data were also thin. The same coverage notes that the review excluded people taking osteoporosis medication, which is the group most likely to be advised to pair a drug with calcium and vitamin D.
The scope of the claim is narrow and specific. Massé and colleagues evaluated routine supplementation to prevent fractures and falls in adults; they did not evaluate whether a person with diagnosed osteoporosis, a measured deficiency or a prescription bone drug should stop a regimen a physician set up. A clinician weighing those cases has a different question from the one the 69 trials answered, and the review says as much by flagging exactly those groups as outside its conclusion.
The review also leaves one policy gap on the table. ScienceAlert cites the authors’ observation that roughly 70% of the clinical guidelines they reviewed still recommend vitamin D supplementation. The PubMed listing for Massé and colleagues’ paper frames the question as how calcium, vitamin D or both affect fracture and fall outcomes in adults; for most older adults, the pooled answer across 153,902 participants is that they hardly do.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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