After studying immune cells taken from the joints of people with rheumatoid arthritis, scientists have found that once the disease sets in, some types of cell lose their sensitivity to vitamin D.
The team — which comprised researchers from University College London and the University of Birmingham, both in the United Kingdom — reports the new findings in the Journal of Autoimmunity.
Rheumatoid arthritis is an autoimmune disease that arises because the immune system attacks healthy tissue — usually the joints — by mistake, leading to painful inflammation and swelling.
The disease often affects several joints at the same time, such as the knees, hands, and wrists. It inflames the lining of the joint and eventually damages the joint itself. This can lead to long-lasting pain, problems with balance, and deformity.
Estimates suggest that approximately 1 percent of the world’s population has rheumatoid arthritis, including around 1.3 million adults in the United States. It affects women more often than men, raising the question of whether hormonal factors may be involved.