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Association between D intake and the risk of rheumatoid arthritis: A meta-analysis

Posted on: September 15, 2012   by  John Cannell, MD


A study involving 215,000 patients deserves a blog. Generally, I don’t write on papers looking at vitamin D intake from food, as the amount in food is meaningless. However, a study with this many people may show an association that smaller studies of vitamin D intake would miss.

In a meta-analysis, Dr Gwan Gyu Song and colleagues of the Korea University College of Medicine, found three studies totaling 215,000 patients that observed vitamin D intake and the onset of rheumatoid arthritis. Over 800 of those 215,000 patients eventually developed rheumatoid arthritis or RA. Dr Song also wanted to know if vitamin D levels were related to RA severity and found eight such studies with 2,800 RA patients to review.

Song GG, Bae SC, Lee YH. Association between vitamin D intake and the risk of rheumatoid arthritis: a meta-analysis. Clin Rheumatol. 2012 Sep 2.

RA is an inflammatory arthritis that often leads to destruction of joint cartilage and fusion of the joints. I have previously blogged on a study tying vitamin D to the increased risk of heart disease in RA patients. Sometimes RA “burns out,” usually after it has destroyed the affected joints. About 1% of the world has RA, usually women.

From the prevention studies, Dr Song and colleagues found that individuals with the highest level of intake from food had a 24% lower risk of developing RA. And of the severity studies, seven of the eight studies found the higher the D levels the less the activity. This strongly implies a treatment effect, at least from sunshine, which is likely where 80% of this vitamin D came from.

Although Dr Song and colleagues only called for more studies, I have spoken with enough rheumatologists treating RA to know, while it will not repair destroyed joints, it helps stop the inflammation in many RA patients. In a contradictory anecdote, however, one rheumatologist reported to me that his rheumatism (rheumatism is a non-specific term for medical problems affecting the joints and connective tissue) was sensitive to both the sun and vitamin D; both seeming to worsen his condition. My guess is that he had an active joint infection of some kind, and the vitamin D mobilized the naturally occurring antimicrobials, causing a “war” in his joints and thus more severe pain and swelling.

My advice: for those with RA, get your vitamin D levels up to 80 ng/ml by taking 5,000 to 10,000 IU/day of vitamin D and testing every three months for both adequacy and excess. Then adjust your dosage to the amount needed to maintain 80 ng/ml throughout the course of the year. For serious diseases, like RA, which can kill via excessive inflammation, I always recommend high normal levels to be sure the immune system has all the building blocks it needs. I also recommend sunshine or low-pressure sunbeds, as we all know UV radiation does more for the immune system then just make vitamin D.

1 Response to Association between D intake and the risk of rheumatoid arthritis: A meta-analysis

  1. [email protected]

    The abstract refers to the people taking a “lot of vitamin D”

    Which is probably 400 IU.

    Other studies have found far more than this 24% decrease in RA when taking >2,000 IU of vitamin D.

    24 RA studies, 96 Osteoporosis studies, 111 studies on bone health, 35 studies on chronic pain, at http://www.vitamindwiki.com/tiki-index.php?page_id=1442

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