Vitamin D and fish oil supplements may reduce risk of autoimmune disease, trial finds | 試驗發現,維生素 D 和魚油補充劑可降低自身免疫性疾病的風險

News Release

With a more pronounced effect after two years of supplementation

Peer-Reviewed Publication

BMJ

Taking daily vitamin D supplements – or a combination of vitamin D and omega-3 fish oil – appears to carry a lower risk of developing autoimmune disease, with a more pronounced effect after two years, finds a trial of older US adults published by The BMJ today.

The researchers say the clinical importance of these findings is high, “given that these are well-tolerated, non-toxic supplements, and that there are no other known effective therapies to reduce rates of autoimmune diseases.”

Autoimmune disease happens when the body’s natural defence system mistakenly attacks normal cells. Common conditions include rheumatoid arthritis, psoriasis, and thyroid diseases, which increase with age, particularly among women.

Both vitamin D and omega-3 fatty acids derived from seafood are known to have a beneficial effect on inflammation and immunity, but no large randomised trials have tested whether these supplements can lower the risk of autoimmune disease.

So researchers set out to test the effects of vitamin D and omega-3 fish oil supplements on rates of autoimmune diseases in 25,871 US adults (average age 67; 51% women; 71% non-Hispanic white).

When they joined the trial, participants provided information on their age, ethnicity, region of residence, income, education, lifestyle, weight, medical history, diet and supplement use. Blood levels of vitamin D and omega-3 fatty acids were also measured.

Participants were then randomly allocated to receive vitamin D (2,000 IU/day) or matched placebo, and omega-3 fatty acids (1,000mg/day) or matched placebo, and were asked to report any diagnosed autoimmune disease over an average 5.3 year period.

These included rheumatoid arthritis, polymyalgia rheumatica (pain and stiffness in the muscles around the shoulders, neck and hips), thyroid disease, and psoriasis, among others.

Reported cases were confirmed using medical records. Those with insufficient documentation for certainty were classed as “probable” cases.

Over the full duration of the trial, a confirmed autoimmune disease was diagnosed in 123 participants in the vitamin D group compared with 155 in the placebo group – a 22% lower relative rate.

In the omega-3 fatty acid group, 130 confirmed cases were diagnosed compared with 148 in the placebo group (a 15% reduction), but this was not a statistically significant result.

However, when probable cases were included, omega-3 fatty acid supplements did significantly reduce the rate by 18% compared with placebo and there was a significant interaction with time, indicating a stronger effect the longer supplements were taken.

Similar results were found when only the last three years of the trial were considered. The vitamin D group had 39% fewer confirmed cases than placebo, while the omega-3 fatty acid group had 10% fewer confirmed cases than placebo. Both vitamin D and omega-3 fatty acid supplements decreased autoimmune disease by about 30% versus placebo alone.

This was a large trial involving a diverse general population with high rates of follow-up and adherence to treatment. However, the researchers acknowledge that they tested only one dose and formulation of each supplement, and say the results may not apply to younger individuals.

Nevertheless, they say this is the first direct evidence that daily supplementation with either agent – or a combination of vitamin D and omega-3 fatty acids – for five years among older US adults reduces autoimmune disease incidence, with more pronounced effect after two years of supplementation.

“We are continuing to follow participants for two years in an extension study to test the time course of this autoimmune disease reduction effect,” they write. “Further trials could test these interventions in younger populations, and those with high autoimmune disease risk.”

[Ends]


News Release

Study finds vitamin D supplements with or without Omega-3s decreased risk of autoimmune diseases

Vitamin D supplementation over five years reduced autoimmune disease rate by 22 percent compared to placebo

Peer-Reviewed Publication

Brigham and Women’s Hospital

Autoimmune diseases (AD) such as rheumatoid arthritis, polymyalgia rheumatica, autoimmune thyroid disease and psoriasis, are a leading cause of morbidity and mortality as people age. Few effective treatments are available for AD, but some preclinical studies have hinted that supplements, including vitamin D and omega-3 (or n-3) fatty acids, may have beneficial effects. In a new study published in BMJ, investigators from Brigham and Women’s Hospital evaluated whether taking vitamin D and/or omega fatty acid supplements could affect rates of AD. The team tested this in the large-scale vitamin D and Omega-3 Trial (VITAL), a randomized study which followed participants for approximately five years. Investigators found the people who took vitamin D, or vitamin D and omega-3 fatty acids had a significantly lower rate of AD than people who took a placebo.

“It is exciting to have these new and positive results for non-toxic vitamins and supplements preventing potentially highly morbid diseases,” said senior author Karen Costenbader, MD, MPH, of the Brigham’s Division of Rheumatology, Inflammation and Immunity. “This is the first direct evidence we have that daily supplementation may reduce AD incidence, and what looks like more pronounced effect after two years of supplementation for vitamin D. We look forward to honing and expanding our findings and encourage professional societies to consider these results and emerging data when developing future guidelines for the prevention of autoimmune diseases in midlife and older adults.”

“Now, when my patients, colleagues, or friends ask me which vitamins or supplements I’d recommend they take to reduce risk of autoimmune disease, I have new evidence-based recommendations for women age 55 years and older and men 50 years and older,” said Costenbader. “I suggest vitamin D 2000 IU a day and marine omega-3 fatty acids (fish oil), 1000 mg a day — the doses used in VITAL.”

VITAL is a randomized, double-blind, placebo-controlled research study of 25,871 men (age 50 and older) and women (age 55 and older) across the U.S., conducted to investigate whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) could reduce the risk for developing cancer, heart disease and stroke in people who do not have a prior history of these illnesses. Participants were randomized to receive either vitamin D with an omega-3 fatty acid supplement; vitamin D with a placebo; omega-3 fatty acid with a placebo; or placebo only. Prior to the launch of VITAL, investigators determined that they would also look at rates of AD among participants, as part of an ancillary study.

“Given the benefits of vitamin D and omega-3s for reducing inflammation, we were particularly interested in whether they could protect against autoimmune diseases,” said JoAnn Manson, MD, DrPH, co-author and director of the parent VITAL trial at the Brigham.

Participants answered questionnaires about new diagnoses of diseases, including rheumatoid arthritis, polymyalgia rheumatica, autoimmune thyroid disease, psoriasis and inflammatory bowel disease, with space to write in all other new onset ADs. Trained physicians reviewed patients’ medical records to confirm reported diagnoses.

“Autoimmune diseases are common in older adults and negatively affect health and life expectancy. Until now, we have had no proven way of preventing them, and now, for the first time, we do,” said first author, Jill Hahn, ScD, post-doctoral fellow at the Brigham.  “It would be exciting if we could go on to verify the same preventive effects in younger individuals.”

Among patients who were randomized to receive vitamin D, 123 participants in the treatment group and 155 in the placebo group were diagnosed with confirmed AD (22 percent reduction). Among those in the fatty acid arm, confirmed AD occurred in 130 participants in the treatment group and 148 in the placebo group. Supplementation with omega-3 fatty acids alone did not significantly lower incidence of AD, but the study did find evidence of an increased effect after longer duration of supplementation.

The VITAL study included a large and diverse sample of participants, but all participants were older and results may not be generalizable to younger individuals who experience AD earlier in life. The trial also only tested one dose and one formulation of each supplement. The researchers note that longer follow-up may be more informative to assess whether the effects are long-lasting.

Disclosures: The authors declare no competing interests.

Funding: This study was funded by the National Institutes of Health grants R01 AR059086, U01 CA138962, R01 CA138962.

Paper cited: Hahn J. et al. “Vitamin D and Marine n-3 Fatty Acid Supplementation and Incident Autoimmune Disease in the VITAL Randomized Controlled Trial” BMJ DOI: 10.1136/bmj-2021-066452


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