Rheumatoid Arthritis, Estrogen, and Menopause
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.