In addition to the other health problems associated with vitamin D deficiency, there is another one. Not having enough vitamin D can make rheumatoid arthritis (and other inflammatory arthritis, possibly) symptoms worse. These findings were reported recently by researchers in the United Kingdom.

In the July issue of Arthritis and Rheumatism, Dr. Sanjeev Patel of St. Helier University Hospital, Carsholton, and colleagues note that there is evidence that vitamin D and its metabolite 25-hydroxyvitamin D (25[OH]D), in particular, may have immunomodulatory effects. (Patel A, Farragher T, Berry J, Bunn D, Silman A, Symmons D. Association between serum vitamin D metabolite levels and disease activity in patients with early inflammatory polyarthritis.of Arthritis Rheum 2007;56:2143-2149).

Metabolites are what vitamin D is converted to in the body. Conversion to different forms of the vitamin can occur in the liver or kidney. Conversion is a common process. Many drugs taken for different diseases undergo this process. In fact, often the metabolite is the active form of the medicine or vitamin. In the case of vitamin D, there are two active metabolites: 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D.

The investigators wanted to find out whether metabolites of vitamin D might have an influence on polyarthritis.

Polyarthritis means a type of arthritis that affects many joints. The prototypical form of polyarthritis is rheumatoid arthritis.

The researchers measured serum levels of 25(OH)D and 1,25- dihydroxyvitamin D (1,25[OH]2D) in 206 patients within 6 months of the onset of symptoms of their disease.

They observed an inverse relationship between baseline levels of 25(OH)D and multiple measures of disease activity. In other words, the lower the vitamin D metabolite levels were, the more symptoms a patient had.

In particular, one measure- the Health Assessment Questionnaire or HAQ- is a common measure of how a patient feels. The researchers found that at baseline, 1,25(OH)2D levels had an inverse relationship with HAQ scores. At 1 year, baseline levels of both metabolites continued to have a significant inverse association with HAQ scores.

According to Dr. Patel, "The results of this study show that vitamin D deficiency may increase rheumatoid arthritis activity. We need to study this further and see if giving vitamin D or more potent drugs with vitamin D activity can relieve symptoms of rheumatoid arthritis."

So what is the message for you if you have rheumatoid arthritis? Make sure your rheumatologist checks your vitamin D levels routinely, particularly in the winter when vitamin D levels can plummet.

If your vitamin D levels are low, you need replacement therapy. In our practice we have noted that patients with vitamin D deficiency often have more flares than patients who have normal vitamin D levels. Vitamin D levels in our patients are monitored routinely.