Although doctors aren't sure what causes rheumatoid arthritis (RA), they do have some ideas. For one thing, they think your genetic background (family history) may play a role. While your genetic background doesn't actually cause RA, it can make you more vulnerable to things in the environment, like bacteria and viruses, that may trigger the condition. The fact that many more women than men are affected has led some experts to believe that female hormones may also play a role in the development of RA.
Common risk factors for RA include:
- Gender. Women account for approximately 70% of RA sufferers. Recent studies show that the incidence of RA in women has increased modestly in the past 15 years whereas the disease had declined in the years prior to that. Experts say many factors may have led to the increase. These include an increase in cigarette smoking in women whilst a similar decline has occurred in men, vitamin-D deficiency and declining estrogen levels in oral contraceptives, among others.
- Age. Although RA can occur at any age, the onset of the disease is most common in adults age 45-65.
- Recent pregnancy. About 80% of women with RA notice an improvement in their symptoms during pregnancy. However, the condition may appear or get worse in the first year after a child is born. This suggests that hormones, or changes in certain hormones, may change the appearance of RA or even shift its incidence from one time period to another. Although this observation has been around for over 50 years, we still don't understand why this happens.
- Genetics. Certain genetic factors predispose people to RA.
- Smoking. Need another reason to quit? We've long known that there are many health risks associated with smoking cigarettes and breathing in secondhand smoke. Recent studies have shown that there's a strong link between smoking and triggering RA as well as increasing its severity if you smoke. Talk to your doctor about the best ways to kick the habit. It is also possible that the lung may be the portal of entry for other environmental triggers for RA – some recent studies have shown that there is a greater incidence of RA in people living near a freeway compared to living in rural areas.