Several forms of arthritis have been linked to HCV infection but this is rare. The type most commonly associated with hepatitis C is rheumatoid arthritis (RA). Blood levels of people with HCV often show elevated levels of rheumatoid factor and it is thought that this may be a trigger to the development of rheumatoid arthritis.
RA normally affects the synovial joints (see figure 1). These are joints with a space between them that is filled with a liquid called synovial fluid. Most joints in the body are of this type. RA causes membranes in these joints to overgrow causing inflammation of the linings of the joints.
Related 2010: Synovial Biopsy Findings in Arthritis Associated with Hepatitis C Virus Infection
Figure 1
Symptoms include pain, swelling, redness and stiffness. As the condition progresses invading inflammatory proteins may damage surrounding cartilage, tendons and bone so affecting joint movement. It is generally thought that HCV related RA is an autoimmune disorder that results in antibodies starting to attack normal body tissue, but some doctors think it may be more closely related to liver damage and argue that the fact that the condition usually affects people who have progressed to cirrhosis supports this.
What are HCV-associated rheumatic diseases?
HCV-associated rheumatic diseases are disorders of the joints and muscles that can result from the HCV virus. Painful joints and muscles combined with fatigue are usually the first and most common complaints.
Less common, but just as important, rheumatic disorders that can occur include joint swelling and inflammation of blood vessels (vasculitis).
The musculoskeletal complications of HCV-associated rheumatic disorders are a reaction to the immune system's fight against the virus. This leads to the formation of immune complexes (formed by the HCV or "antigen" combining with the patient's antibody against HCV) as well as the production of abnormal proteins called cryoglobulins.
Cryoglobulinemia
In the paper, which appears online in the journal Environmental Health Perspectives, a spatial analysis led by VerĂ³nica Vieira, MS, DSc, associate professor of environmental health, found that women in states like Vermont, New Hampshire and southern Maine were more likely to report being diagnosed with RA.
"There's higher risk in the northern latitudes," Vieira said. "This might be related to the fact that there's less sunlight in these areas, which results in a vitamin D deficiency."
The study looked at data from the Nurses' Health Study, a long-term cohort study of U.S. female nurses. Looking at the residential addresses, health outcomes and behavioral risk factors for participants between 1988 and 2002, researchers based their findings on 461 women who had RA, compared to a large control group of 9,220.
RA is a chronic inflammatory disease that affects the lining of the joints, mostly in the hands and knees. This chronic arthritis is characterized by swelling and redness and can wear down the cartilage between bones. RA is two to three times more common in women than in men.
Although the cause of RA is unknown, the researchers wrote, earlier studies have shown that vitamin D deficiency, which can be caused by a lack of sunlight, has already been associated with a variety of other autoimmune diseases.
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