Rheumatoid arthritis (RA) is a disease caused by an abnormal body defense system—your immune system misfires, attacking normal joint tissues. Researchers think RA is caused by a combination of the genes you were born with and something that triggers those genes to cause RA. One of the triggers could be the female hormone estrogen. It makes sense, since 70% of people with RA are women. But we still have a lot to learn about RA and estrogen before we can know for sure. RA and the Role of Estrogen There is evidence that low levels of estrogen may trigger RA and high levels of estrogen may offer some protection: When a woman with RA gets pregnant, there is about a 70% chance her RA symptoms will get better during the pregnancy. This seems to correlate with the rise in estrogen. About six weeks after childbirth, when these hormones return to normal, many women have a relapse of RA symptoms. Studies show women who have low levels of estrogen due to early menopause, at about age 45 or younger, have an increased risk of RA compared with women who have normal-onset menopause. Risk of developing RA peaks for women at ages 50 to 54, the normal age of menopause, based on a study of more than 120,000 women. All this evidence suggests that estrogen protects some women against RA. But it doesn't explain why women who continue to get their periods and have plenty of estrogen are still three times more likely than men to have RA. And studies have not been able to show that giving women estrogen replacement therapy at the time of menopause reduces their risk of RA. The exact role of estrogen in RA remains a bit of a mystery. RA, Osteoporosis, and Menopause If you have RA and you're going through menopause, you're at increased risk of osteoporosis. Osteoporosis is the thinning of your bones. The decrease in estrogen that occurs during menopause is one risk factor for osteoporosis. Here are others related to RA: RA itself may increase bone loss, especially around affected joints. Steroid medications given for RA increase bone loss. Inactivity because of pain and stiffness from RA increases bone loss. Your doctor may want you to undergo a bone density test, which can diagnose osteoporosis and let you know whether you are in danger of a bone fracture. The test is painless and takes only a few minutes. Here are the best ways to protect yourself from osteoporosis during and after menopause: Eat a balanced diet with plenty of calcium and vitamin D. Do regular aerobic and weight-bearing/strengthening exercises. Don't smoke. Drink alcohol only in moderation (one drink or fewer per day). Depending on your health, your doctor may recommend taking a calcium/vitamin D supplement and/or a bisphosphonate drug, a prescription medication to stop bone loss. Key Takeaways The female hormone estrogen may have some protective effects in RA. Studies show that taking estrogen does not help prevent RA. Menopause may be a time of higher risk for women to develop RA. Women who have RA may be at higher risk of osteoporosis than other women after menopause.