Why do so many middle-aged women develop rheumatoid arthritis (RA)? Women are three times more likely to develop the condition—and researchers have identified a series of risk factors, including HRT (hormone replacement therapy), and starting menopause early.
HRT increases the risk by around 46 percent, as does an early menopause, and having a hysterectomy is another risk factor, say scientists from the Anhui Medical University School of Public Health in China.
RA is triggered by changes in levels of estrogen and progesterone, which is why the disease is far more common in women, but it had been assumed that HRT would have a protective effect as it boosts estrogen levels after the menopause—but it seems to be doing something else as well, the researchers fear.
It appears to affect the levels of other hormones, and “adversely affects joint health”, lead researcher Rieke Alten suggests.
The researchers studied the health of 223,526 women registered with the UK Biobank for 12 years, during which time 3313, or 1.5 percent, developed RA.