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Study finds an association between vitamin D and rheumatoid arthritis in 15 countries

Posted on: July 11, 2017   by  Vitamin D Council


Rheumatoid arthritis (RA) is a common form of arthritis, affecting approximately 1.3 million individuals in the United States. Some comorbidities of RA include an increased risk of cardiovascular disease, stroke, heart failure and infections such as tuberculosis.

A post hoc analysis of the COMORA study, published in the International Journal of Rheumatology, found that vitamin D status was associated with rheumatoid arthritis.

The Comorbidities in Rheumatoid Arthritis (COMORA) study analyzed data from 1,431 patients with RA across 15 countries. Disease activity was determined by DAS28 score, with higher scores indicating an increased severity of RA. Functional status of the patients was determined by a self-administered questionnaire. Patients were also asked to report prescription drug use and supplement intake. Vitamin D status was determined by a serum 25(OH)D collection at baseline of the study. The researchers defined vitamin D deficiency as 30 ng/ml.

This is what the researchers found:

  • The average vitamin D status was 27.3 ng/ml, and approximately 55% of patients fell in the insufficient range.
  • Patients with vitamin D insufficiency had more comorbidities and were significantly associated with lung diseases and osteoporosis therapy ( p= 0.006 and p=0.04, respectively).
  • Vitamin D status was inversely correlated with RA disease activity (p< 0.001).

The researchers summarized their findings:

“A status of low level of vitamin D is common in RA in different countries and under different latitudes… Many factors related to patients and their disease seem to be associated with low levels of vitamin D.”


Hassouni, N. Mawani, N. Allali, F. Rkain, H. et al. Research Article Evaluation of Vitamin D Status in Rheumatoid Arthritis and Its Association with Disease Activity across 15 Countries: (The COMORA Study). International Journal of Rheumatology, 2017.

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