25-hydroxyvitamin D → Depression

Mechanism

Observational papers have tied low 25(OH)D to later depression. The vitamin D receptor is expressed in brain. Reverse causation can produce the same correlation: people who are sliding stay indoors, and the number falls. Okereke, Reynolds, Mischoulon, Vyas, and colleagues tested 2000 IU a day of cholecalciferol inside VITAL. VITAL-DEP followed 18353 US adults aged 50 and older (mean 67.5) who were free of clinically relevant depressive symptoms at baseline. Median treatment was 5.3 years. The primary was depression or clinically relevant depressive symptoms, incident plus recurrent: a clinician diagnosis, new treatment, or a PHQ-8 of 10 or more. There were 609 events on vitamin D3 (12.9 per 1000 person-years) and 625 on placebo (13.3). The hazard ratio was 0.97 (95% CI 0.87 to 1.09, P=.62). Incident and recurrent splits were also null. PHQ-8 change differed by 0.01 points (-0.04 to 0.05). The authors had set 0.5 as the smallest change that would matter. Mean baseline 25(OH)D was 30.8 ng/mL. Subgroups, including baseline 25(OH)D, did not move the result. Rahman and colleagues read depression inside D-Health, a five-year Australian trial of monthly 60,000 IU versus placebo. PHQ-9 in 20487 people differed by 0.02 (-0.06 to 0.11). Clinically relevant depression (PHQ-9 of 10 or more) had an odds ratio of 0.99 (0.90 to 1.08). New antidepressant use in 16670 people had a hazard ratio of 1.04 (0.96 to 1.12). People already on antidepressants sat 0.25 PHQ-9 points lower. That is not the primary. Alavi and colleagues assigned 50,000 IU a week versus placebo for eight weeks in 78 clinic patients aged 60 and older who already had moderate to severe depression. GDS-15 fell from 9.25 to 7.48 on vitamin D. The placebo arm did not fall. That is a treatment trial in people already under care, not the prevention contrast.

Caveats

VITAL-DEP is prevention in people without current depression or treatment. It is not a trial of treating major depression. Participants could take up to 800 IU a day outside the study. Mean baseline 25(OH)D was already adequate. Few people were deficient. Events came from annual questionnaires: a diagnosis, new treatment, or a PHQ-8 of 10 or more. A subset sat an in-person interview. D-Health used a monthly bolus, not a daily pill. The sample was older Australians. Depression was a PHQ-9 and a prescribing record, not a structured interview. Subgroup signals in people already on antidepressants, or with predicted 25(OH)D under 50 nmol/L, do not rewrite the primary. Alavi is 78 people, eight weeks, three psychiatric clinics, already in treatment, and abstract only. The published contrast leans on a within-group GDS drop. It does not flip the identifying files. This page is not employment, income, or cognition. It is not an argument against treating a true deficiency. This is not medical advice and not a recommendation to take or skip a pill.

Effect

odds_ratio = 0.97. Okereke 2020 VITAL-DEP: HR 0.97 (95% CI 0.87-1.09), 609 vs 625 events, N=18353. PHQ-8 MD 0.01 (-0.04 to 0.05). Rahman 2023 D-Health: PHQ-9 MD 0.02 (-0.06, 0.11), N=20487.

Nodes

Named confounders

• Time outdoors
• Educational attainment
• Disposable income

Papers

• Effect of Long-term Vitamin D3 Supplementation vs Placebo on Risk of Depression or Clinically Relevant Depressive Symptoms and on Change in Mood Scores: A Randomized Clinical Trial.

  OI Okereke, CF Reynolds, D Mischoulon, G Chang, CM Vyas, NR Cook, A Weinberg, V Bubes · 2020 · JAMA

• Effect of vitamin D supplementation on depression in older Australian adults.

  ST Rahman, M Waterhouse, BD Romero, C Baxter, DR English, OP Almeida, M Berk, PR Ebeling · 2023 · International journal of geriatric psychiatry

• Effect of vitamin D supplementation on depression in elderly patients: A randomized clinical trial.

  NM Alavi, S Khademalhoseini, Z Vakili, F Assarian · 2020 · Clinical nutrition (Edinburgh, Scotland)