A number of studies indicate a clear link between cigarette smoking and rheumatoid arthritis. Rheumatoid arthritis (RA) is a debilitating disease of the immune system that affects the joints, usually the hands and feet, causing swelling, pain and sometimes deformity. It is approximately 3 times more common in women than in men. To understand the link between smoking and RA, we need to know about rheumatoid factor.

Rheumatoid factor (RF)
Rheumatoid factor (also known as RF) is an antibody found in the blood of 7 out of 10 people with rheumatoid arthritis. Only one in 20 people without RA test positive for rheumatoid factor. The higher the level of rheumatoid factor, usually the more severe the rheumatoid arthritis is. The concentration of rheumatoid factor ebbs and flows along with inactivity and flare ups of the disease.

Smokers and rheumatoid arthritis
Interestingly, studies of people with rheumatoid arthritis have shown that smokers are more likely to be positive for rheumatoid factor. Moreover, a study published in 2000 has shown that people with RA who smoked for longer had higher levels of rheumatoid factor in their blood than those who didn't. This usually indicates more severe rheumatoid arthritis. The study also showed that people who smoked for more than 20 years were found to have more severe disease in terms of damage shown on X-rays, but not necessarily more active disease in terms of tender, painful joints.

Smokers without rheumatoid arthritis
A Finnish study of healthy people without rheumatoid arthritis also found that those who smoked were much more likely to have raised rheumatoid factor than those who didn't smoke. These findings may show that smoking makes it more likely for people to get rheumatoid arthritis by inducing the rheumatoid factor. The people in the study are being followed up to see if they go on to develop RA.

Other factors
Researchers do not yet fully understand the effect of smoking on rheumatoid arthritis, but smoking does affect the immune system and sex hormones, and smokers have been found to have abnormalities in their white blood cells (which are involved in fighting infection and inflammation).

Clearly, there are many factors at play in the development of RA and researchers have suggested that having a genetic predisposition to the disease may be involved in addition to environmental factors.

Risk for smokers
So, while the exact nature of the mechanism linking smoking to rheumatoid arthritis remains unclear, there is no doubt that a link does exist. Recent research presented at the American College of Rheumatology Annual Scientific meeting in 2000 indicates that the risk of developing rheumatoid arthritis is nearly double for a woman who currently smokes, compared with a woman who is a non-smoker. The risk of developing rheumatoid arthritis is lower for former smokers compared with current smokers, but higher than for people who have never smoked.

Quitting
The good news is that you can do something about smoking and that stopping may well lower your risk of developing this debilitating condition.