By David Liu, PHD

Thursday Dec 13 2012 (foodconsumer.org) -- A new study in Clinical Rheumatology suggests that vitamin D deficiency or insufficiency may increase risk of developing rheumatoid arthritis or increased rheumatoid arthritis activity.

G. G. Song from Korea University Anam Hospital, Korea University College of Medicine in Seoul, South Korea and colleagues meta-analyzed data from previous studies and found individuals with low serum vitamin D were at high risk for rheumatoid arthritis and increased disease activity.

The meta-analysis was based data from three cohort studies of 215,757 participants with 874 incident cases of rheumatoid arthritis identified and eight studies on the association between serum vitamin D concentrations and rheumatoid arthritis activity in 2885 rheumatoid arthritis patients and 1,084 controls without the disease.

Participants who had the highest intake of total vitamin D were 24 percent less likely to develop rheumatoid arthritis. compared with those who had the lowest intake. The association was found in all studies.

Among those who took vitamin D supplements, those taking highest amounts of vitamin D were 23.6% less likely to develop rheumatoid arthritis, compared with those taking lowest amounts.

Serum vitamin D levels were inversely associated with rheumatoid arthritis activity in all except for one which had a different result likely because many of the 85 rheumatoid arthritis in the study suffered vitamin D deficiency.

 The researchers concluded "Meta-analysis of 215,757 participants suggests that low vitamin D intake is associated with an elevated risk of RA (rheumatoid arthritis) development. Furthermore, available evidence indicates that vitamin D level is associated with RA (rheumatoid arthritis) activity."