Evidence question

PubMed sourcedAbstract-based analysisUpdated Sep 2026Human reviewedUpdated Aug 2026

Evidence / Longevity & Preventive Medicine

CoverageLongevity & Preventive Medicine

Does vitamin D supplementation reduce mortality or major disease?

Reviewed by Neal Rouzier, MD, Preventive Medicine · Aug 2026

Updated Aug 2026·11 studies analyzed·2 core studies·Applies to: postmenopausal women

Bottom line

Meta-analyses show vitamin D supplementation does not significantly reduce all-cause mortality in unselected populations. Targeted repletion may benefit those with documented deficiency.[1–6]

Evidence confidence

Evidence Confidence

High
LimitedModerateHigh

Multiple high-quality studies directly address this question, with generally consistent findings.

Key uncertainty. Mortality benefit in deficient subgroups remains debated; many trials enrolled largely replete populations.

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Also asked

Vitamin D supplementation evidence▼

Meta-analyses show vitamin D supplementation does not significantly reduce all-cause mortality in unselected populations. Targeted repletion may benefit those with documented deficiency.

Vitamin D prevention▼

Meta-analyses show vitamin D supplementation does not significantly reduce all-cause mortality in unselected populations. Targeted repletion may benefit those with documented deficiency.

Body of evidence

Clinical Evidence Brief

RAGMD analyzed 9 relevant studies.

Overall finding

6 studies address mortality, with weighted findings showing benefit. 3 studies address hba1c / glycemic control, with weighted findings showing mixed findings. 2 studies address ldl-c, with weighted findings showing harm. 2 studies address weight / body composition, with weighted findings showing unclear findings. 3 randomized or systematic-review reports and 1 observational study address treatment. Test and replete documented vitamin D deficiency rather than supplementing unselected populations for mortality prevention.

Evidence by outcome

Direction: ↑ Favors treatment / reassuring · ↓ Harm signal · ↔ No clear effect · ± Mixed · ↗ Observational link · ? Unclear

Favors treatment

Mortality

high · 6 studies

6 studies address mortality, with weighted findings showing benefit. This is an objectively measured outcome. This is a hard clinical endpoint.

Objectively measured · Hard clinical endpoint

Studies

PMID 31405892PMID 24349197PMID 30415628PMID 37914564PMID 40616152PMID 34637926
Mixed

HbA1c / glycemic control

moderate · 3 studies

3 studies address hba1c / glycemic control, with weighted findings showing mixed findings. This is an objectively measured outcome. This is a surrogate endpoint and does not by itself prove a hard clinical outcome.

Objectively measured · Surrogate endpoint

Studies

PMID 42426860PMID 23824417PMID 42588058
Harm signal

LDL-C

moderate · 2 studies

2 studies address ldl-c, with weighted findings showing harm. This is an objectively measured outcome. This is a surrogate endpoint and does not by itself prove a hard clinical outcome.

Objectively measured · Surrogate endpoint

Studies

PMID 30415628PMID 42588058
Unclear

Weight / body composition

moderate · 2 studies

2 studies address weight / body composition, with weighted findings showing unclear findings. This is an objectively measured outcome. This is a surrogate endpoint and does not by itself prove a hard clinical outcome.

Objectively measured · Surrogate endpoint

Studies

PMID 42426860PMID 23824417
Harm signal

Major adverse cardiovascular events

moderate · 1 study

1 study addresses major adverse cardiovascular events, with weighted findings showing harm. This is an objectively measured outcome. This is a hard clinical endpoint.

Objectively measured · Hard clinical endpoint

Studies

PMID 30415628
Unclear

Sexual activity

moderate · 1 study

1 study addresses sexual activity, with weighted findings showing unclear findings. This is a patient-reported / subjective outcome.

Patient-reported

Studies

PMID 23824417

Magnitude / clinical importance

Effects were statistically detectable in some analyses but generally small.

Small domain-specific changes can still matter to patients, especially for symptoms, but they should not be described as large clinical effects.

Agreement across studies

Most studies agree on sexual activity (unclear findings), while mortality findings are benefit and less consistent across domains.

Supports main conclusion: 3 · Neutral / mixed: 5 · Credible conflicting: 1

Study counts describe the landscape; RAGMD weights studies according to design, quality, and directness.

Conflicting findings

  • Among patients with elevated triglyceride levels despite the use of statins, the risk of ischemic events, including cardiovascular death, was significantly lower among those who received 2 g of icosa…
  • Growth hormone (GH) deficiency (GHD) is one of the most prevalent deficiencies in patients with hypopituitarism and several cohort studies have demonstrated an increased mortality risk in hypopituita…
  • Magnesium supplementation does not appear to improve insulin resistance in individuals with diabetes or prediabetes significantly.
  • The present meta-analysis of intervention studies shows that DHEA supplementation in elderly men can induce a small but significant positive effect on body composition that is strictly dependent on D…

Risks & harms

5 studies report safety-relevant findings. Design mix: Systematic review / meta-analysis, Randomized controlled trial, Narrative review. Rare-event inference should not rest on underpowered trials alone.

Who this applies to

Most studies included postmenopausal women.

What remains uncertain

  • Mortality benefit in deficient subgroups remains debated; many trials enrolled largely replete populations.
  • Mortality benefit in deficient subgroups remains debated; many trials enrolled largely replete populations.
  • Surrogate improvement does not prove a hard clinical outcome.

Clinical takeaway

Test and replete documented vitamin D deficiency rather than supplementing unselected populations for mortality prevention. Targeted repletion may be appropriate in deficiency; broad supplementation lacks mortality benefit in meta-analyses.

Favors treatment

Mortality?

Benefit

high[31405892 · 24349197 · 30415628 · 37914564 · 40616152 · 34637926]

Mixed

HbA1c / glycemic control?

Mixed findings

moderate[42426860 · 23824417 · 42588058]

Harm signal

LDL-C?

Harm

moderate[30415628 · 42588058]

Unclear

Weight / body composition?

Unclear findings

moderate[42426860 · 23824417]

Harm signal

Major adverse cardiovascular events?

Harm

moderate[30415628]

Unclear

Sexual activity?

Unclear findings

moderate[23824417]

Unclear

Quality of life?

Unclear findings

moderate[23824417]

Mixed

Blood pressure?

Mixed findings

limited[42588058]

3 randomized or systematic-review reports and 1 observational study address treatment. Weighted treatment findings show benefit.

3 RCT / systematic review · 1 observational

Large randomized trials strongly influence the conclusion

2 landmark studies with randomized or systematic-review designs strongly inform this conclusion.

Supporting studies provide additional context

9 supporting studies add context beyond the core evidence base.

Regimen & duration

Differences in hormone type, dose, duration, and patient population affect how results should be interpreted.

Long-term uncertainty

Evidence beyond long follow-up windows and in certain subgroups remains less complete.

9 analyzed studies

Strongest evidence

PloS one2013

Landmark studyPMID 24349197

Meta-analysis of long-term vitamin D supplementation on overall mortality.

INTRODUCTION: It has been suggested that vitamin D is effective to prevent mortality. However, there is no consistent conclusion that the effects of vitamin D supplementation on all-cause mortality are associated with duration of treatment.

Systematic review
Evidence
Relevance

Supporting literature

Cardiovascular Risk Reduction with Icosapent Ethyl for Hypertriglyceridemia.

Oral magnesium supplements and insulin resistance in individuals with diabetes and pre-diabetes: an updated systematic review and meta-analysis of randomized controlled trials.

Dehydroepiandrosterone supplementation in elderly men: a meta-analysis study of placebo-controlled trials.

+6 more

More in this focus area

Related evidence analyses

Other structured clinical questions in Longevity & Preventive Medicine.

Does magnesium supplementation improve metabolic health markers?

Trials in deficient or at-risk individuals show modest improvements in some glycemic and blood pressure markers, but routine supplementation for metabolic disease prevention is not strongly supported in general populations.

11 linked studies

Does DHEA supplementation improve health outcomes in aging adults?

DHEA raises circulating androgens and estrogens modestly but lacks robust outcome trial evidence for cardiovascular, cognitive, or mortality benefit in healthy aging adults without documented deficiency.

11 linked studies

When is growth hormone replacement appropriate in adults?

Growth hormone replacement is evidence-supported for adults with confirmed GH deficiency from pituitary disease, improving body composition and quality of life. Use in healthy aging or performance enhancement lacks safety and efficacy evidence.

11 linked studies

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