Falls · VITD-FALL-01 · v2
The biggest and best-run trials of vitamin D pills tested for falls found no benefit at all: a 25,871-person US trial [12], a 21,315-person Australian trial [16], and a 5,108-person New Zealand trial [6] each showed no reduction in falls. Several trials also found that high doses made falls more common rather than fewer [3][9][13]. A smaller trial did show fewer falls, but only in women who were vitamin-D-deficient to begin with [14], and another found benefit only when the pills were paired with exercise, not from vitamin D by itself [17]. One study reporting benefit was observational and cannot prove cause [21]. Taken as a blanket statement about older adults in general, the trial evidence points to no benefit and sometimes harm, which is why the panel did not uphold the claim.
The corpus is dominated by large, low-bias RCTs that are uniformly null for falls: VITAL (N=25,871, OR 0.97, 95% CI 0.90-1.05) [12], D-Health (N=21,315, OR 1.02, 95% CI 0.95-1.10) [16], and ViDA (N=5,108, HR 0.99, 95% CI 0.92-1.07) [6]. STURDY found no fall prevention at 1,000 IU/d or higher and raised explicit safety concerns [13], and Uusi-Rasi found neither vitamin D nor exercise reduced the rate of falls [4][15]. High doses were associated with more falls, not fewer: increased incidence at 60,000 IU monthly [3], an IRR of 2.33 in long-term-care residents [9], and a U-shaped curve where high daily doses raised falls relative to medium doses (OR 5.6, 95% CI 2.1-14.8) [10]. Supportive signals were confined to a deficient postmenopausal fallers trial [14], a combined exercise-plus-vitamin-D arm [17], and one cross-sectional association [21]. The contested point: The division is between the unqualified general claim and a narrower deficiency-correction effect: the one clean supportive RCT [14] enrolled women deficient at baseline (25(OH)D 15.0 ng/mL), and the medium-dose benefit in [10] occurred in a low-25(OH)D population. The question is whether a real effect of correcting deficiency is being masked when averaged across replete, unselected older adults in whom the large trials [12][16][6] found nothing.
All 21 papers behind this claim with their DOIs and what each does to it, the panel’s arbitration, the evidence gap map and the open research questions. Free, and sent to your inbox.
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One reviewer's only job is to attack the finding. The challenges below were weighed before the grade was set.
The three largest, least-biased RCTs (VITAL [12] OR 0.97, D-Health [16] OR 1.02, ViDA [6] HR 0.99) are all null, directly contradicting the unqualified claim.
Dose-dependent harm: [3] and [9] show increased falls at high dose, [10]'s high-dose arm shows no benefit (OR 5.6 vs medium), and [13] raised explicit safety concerns — the net direction opposes the claim.
Where it remains uncertain. The only clean supportive RCT [14] was in vitamin-D-deficient fallers, and [17]'s benefit required co-administered exercise, so any effect may be confined to correcting deficiency rather than general supplementation.
Aleatory
Participants ranged from deficient (15.0 ng/mL in [14]) to replete (mean 77 nmol/L in [12]), so individual fall response to supplementation is inherently variable across the population.
Epistemic
Benefit appears only where baseline 25(OH)D was low ([14]; medium-dose arm of [10]), but the large trials did not enrol for deficiency, leaving the deficient-only effect untested at scale [12].
Inferential
[21] is cross-sectional and retrospective, so its lower fall frequency with cholecalciferol cannot establish causation.
The load-bearing papers from a corpus of 21, each classified by what it does to the claim. Every DOI is taken from the corpus the claim was graded on.
N=5108 RCT; falls HR 0.99 (95% CI 0.92-1.07), null.
“High-dose bolus vitamin D supplementation of 100 000 IU colecalciferol monthly over 2·5-4·2 years did not prevent falls or fractures in this healthy, ambulatory, adult population.”
Panel auditInternal validity: medium · scope of inference: Healthy ambulatory adults aged 50-84 in New Zealand, mostly not vitamin D deficient.Key limitations: falls were post-hoc · bolus monthly dosing · healthy replete population
Dose-dependent, non-monotonic effect; no benefit at commonly used doses.
“There was no decrease in falls on low vitamin D doses 400, 800 IU, a significant decrease on medium doses 1600, 2400,3200 IU (p=0.020) and no decrease on high doses 4000, 4800 IU compared to placebo (p=0.55).”
Panel auditInternal validity: medium · scope of inference: Elderly women (mean age 66) with baseline 25OHD below 20 ng/ml; effect depends on dose.Key limitations: falls secondary outcome · U-shaped dose response; higher doses increased falls · per-arm samples small
Largest dedicated falls analysis (N=25,871); null (OR 0.97, 95% CI 0.90-1.05).
“Daily supplemental vitamin D3 vs placebo did not decrease fall risk in generally healthy adults not selected for vitamin D insufficiency.”
Panel auditInternal validity: high · scope of inference: Generally healthy US adults (men 50+, women 55+) not selected for vitamin D insufficiency.Key limitations: not selected for deficiency · falls self-reported · mostly vitamin-D-replete at baseline
Higher monthly doses increased falls.
“they had no benefit on lower extremity function and were associated with increased risk of falls compared with 24,000 IU.”
Panel auditInternal validity: medium · scope of inference: Community-dwelling men and women 70+ with a prior fall, comparing vitamin D doses rather than vitamin D vs none.Key limitations: no placebo arm · dose comparison not supplementation vs none · small sample
4 of 21 papers shown. The full review lists all of them, with the panel’s arbitration →
Claims are graded at each quarterly release, and re-graded between releases only when a pivotal trial lands. Every change is a new version of the claim.
Multiple large, well-powered, low-bias RCTs show no reduction in falls and several show increased falls, so the blanket claim is refuted outside possible deficiency subgroups.
Release 2026-q4 re-graded every claim from its corpus under protocol v0.19. An earlier release's grade is shown for the record; it came from an earlier protocol and is not a movement.
Assumptions that carry weight but are not themselves established.
The panel records the gap that would most move the claim, and the study that would close it.
Daily moderate-dose vitamin D in confirmed-deficient older adults. Benefit is confined to deficient populations ([14]; medium-dose arm of [10]) while the large null trials did not select for deficiency [12][16], so the deficiency-restricted effect is untested at scale. The panel rates this the highest-importance open gap for the claim, and names the study design that would close it: Large RCT enrolling only older adults with low baseline 25(OH)D, daily moderate dose, falls as the primary outcome.
Open question: Does daily moderate-dose vitamin D reduce falls specifically in older adults who are vitamin-D-deficient at baseline? Why it is still open: The only clean supportive RCT [14] was in deficient younger postmenopausal fallers, and the large null trials did not enrol for deficiency [12][16].
Priors is a sceptical first reader, not peer review, and not medical advice.
Release 2026-q4 · graded 26 Oct 2026 · protocol v0.19