VITAL Trial: Vitamin D and Autoimmune Disease Risk

Last reviewed 2026-10-04 by Jack Mayeux, APRN, FNP. This page is clinical content and is reviewed on a regular schedule.

Medically reviewed by Jack Mayeux, FNP

In a 25,871-person trial, 2,000 IU of vitamin D a day was linked to 22% fewer new autoimmune diseases over 5 years.

This article walks through the BMJ (2022) (https://doi.org/10.1136/bmj-2021-066452) paper in plain English: what was studied, what changed, what the limits are, and what it does not prove. Full citation and DOI link (https://doi.org/10.1136/bmj-2021-066452) are at the end, with a PubMed record (https://pubmed.ncbi.nlm.nih.gov/35082139/).

What the study found

VITAL was a nationwide, randomized, double-blind, placebo-controlled trial with a 2x2 factorial design, enrolling 25,871 US adults (men 50 and older, women 55 and older). Participants took vitamin D (2,000 IU/day), omega-3s (1,000 mg/day), both, or placebos, and autoimmune diagnoses were confirmed by medical record review over a median of 5.3 years.

Vitamin D was associated with a 22% lower rate of confirmed autoimmune disease (123 vs 155 cases, HR 0.78), while the 15% lower rate with omega-3s was not statistically significant. The vitamin D result was borderline (P=.05), and VITAL's primary heart and cancer outcomes were null.

Key finding (from the study record): Vitamin D 2,000 IU/day for ~5.3 years: confirmed autoimmune disease HR 0.78 (123 vs 155 cases), a 22% reduction; omega-3 HR 0.85 (NS).

How the study was done

• Design: Nationwide double-blind 2x2 factorial RCT (VITAL) • Who was studied: 25,871 adults (men >=50, women >=55) • Journal / year: BMJ (2022) • First author: Hahn J et al.

From the abstract: OBJECTIVE: To investigate whether vitamin D and marine derived long chain omega 3 fatty acids reduce autoimmune disease risk. DESIGN: Vitamin D and omega 3 trial (VITAL), a nationwide, randomized, double blind, placebo controlled trial with a two-by-two factorial design. SETTING: Nationwide in the United States.

What it means — and what it does not

Useful takeaway: In a 25,871-person trial, 2,000 IU of vitamin D a day was linked to 22% fewer new autoimmune diseases over 5 years.

Limits and caveats: Borderline significance (P=.05); older adults; omega-3 arm not significant. VITAL's main cancer/CVD outcomes were null.

This evidence can inform a conversation with a licensed provider. It is not a guarantee of similar results for you, and it is not a recommendation to start, stop, or change any medication on your own.

How this connects to care

A2Z serves men in Utah with telehealth evaluation, labs, and provider-guided plans when appropriate. The TRT program is $149/month and includes initial labs only. Tadalafil and enclomiphene, sermorelin, and tirzepatide (compounded, not FDA-approved) are separate products.

Relevant pages on this site:

• TRT program (https://a2ztrt.com/trt)

FAQ

What did this study actually find?

In a 25,871-person trial, 2,000 IU of vitamin D a day was linked to 22% fewer new autoimmune diseases over 5 years. The design was: Nationwide double-blind 2x2 factorial RCT (VITAL). Population: 25,871 adults (men >=50, women >=55).

Does this mean I should start treatment?

No. Research informs care; it does not prescribe it. A licensed provider reviews your symptoms, labs, and history before any decision. Results vary.

What are the main limits of this evidence?

Borderline significance (P=.05); older adults; omega-3 arm not significant. VITAL's main cancer/CVD outcomes were null.

Keep reading

• TRT and Insulin Sensitivity in Men With Type 2 Diabetes (https://a2ztrt.com/post/testosterone-insulin-sensitivity) • Can You Drink Alcohol on TRT? What Men Should Know (https://a2ztrt.com/post/can-you-drink-alcohol-on-trt) • Does TRT Cause Hair Loss? What the Evidence Actually Says (https://a2ztrt.com/post/does-trt-cause-hair-loss) • What Is a Normal Testosterone Level, Really? (https://a2ztrt.com/post/what-is-a-normal-testosterone-level)

Practical questions to bring to a consult

Research is most useful when it turns into better questions:

• Do my symptoms and labs line up with the kind of men this study enrolled? • Which of the study’s limits apply to me (age, heart risk, anemia, fertility goals, medications)? • What monitoring would we use if we tried a related therapy — hematocrit, PSA, glucose, sleep, or something else? • Are we talking about a branded FDA-approved medication, a different formulation, or a compounded product that is not FDA-approved?

A short, honest consult is the right place for those answers — not a social post. Start a free consult in Utah (https://a2ztrt.com/contact).

Reference

Hahn J et al. Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial. BMJ. 2022. https://doi.org/10.1136/bmj-2021-066452 (https://doi.org/10.1136/bmj-2021-066452) · PubMed 35082139 (https://pubmed.ncbi.nlm.nih.gov/35082139/).

Next step

Start a free consult in Utah (https://a2ztrt.com/contact). Bring your questions — including anything this study raised for you.

The TRT program is $149/month and includes initial labs only. Tadalafil and enclomiphene, sermorelin, and tirzepatide (compounded, not FDA-approved) are separate products.

Talk to a licensed provider. Results vary. Not medical advice.