Is Rheumatoid Arthritis Caused By Cigarette Smoking?

The results of several large studies conducted in the past two decades support the association between cigarette smoking and the development of RA.

In one study, researchers in Finland studied 512 patients with RA. They found that men who smoked in the past but had stopped smoking were 2? times more likely to develop RA than those who never smoked. For men who were currently smoking, the risk of RA was almost 4 times greater.

In Manchester, England, medical scientists evaluated the risk of smoking in pairs of twins where one twin had RA and the other did not. These scientists used a questionnaire to record information about the twin's smoking history. They found that if one of the pair of twins smoked, the other was also likely to smoke. In those twin pairs where one twin smoked and the other didn't, the smoker had a much higher risk of developing RA than the twin who didn't smoke. This was true in both identical twin and fraternal twin pairs.

In the United States, doctors studied the medical records of more than 30,000 women between the ages of 55 and 69 years who had enrolled in the Iowa Women's Health Study. These physicians found that the incidence of RA was almost double in those women who were currently smokers as compared to the incidence in nonsmokers. The risk of developing RA also appeared to be lower for former smokers as compared to current smokers; the risk of RA was higher in the former smokers as compared to those who never smoked. For women who had stopped smoking at least ten years prior to the start of the study, however, this risk was decreased to the same level as the risk for women who had never smoked. The U.S. doctors were not able to give a definitive reason for the association between smoking and RA in women. Some investigators in this study suggested that an interaction between the inhaled smoke and the woman's immune system might be the culprit. Others suggested that smoking might lower the level of estrogen, which in turn might increase the risk of RA. These researchers also mentioned that in other related studies, smoking was shown to raise the level of rheumatoid factor in the body.

These studies indicate that cigarette smoking significantly increases the risk of RA in both men and women. This risk of developing RA can be added to the long list of problems associated with tobacco use, such as lung, mouth, and throat cancer; emphysema; and heart disease. If you use tobacco, please discuss options for quitting with your physician. Quitting can save your joints and your life.