• Posted January 10, 2024

Hormonal Changes May Help Trigger Rheumatoid Arthritis in Women

Women are four to five times more likely than men to develop early-onset rheumatoid arthritis, and a few hormonal factors could be why, new research suggests.

Entering menopause early (before age 45), taking hormone replacement therapy (HRT), and having four or more kids are all related to heightened odds for developing rheumatoid arthritis, the study found.

Rheumatoid arthritis is an autoimmune disease in which the body's immune system attacks its own tissue, including the joints. Damage can progress to other organs.

It's long been known that women face higher risks for the disease than men, and a team led by Dr. Hai-Feng Pan at Anhui Medical University School of Public Health in Hefei, China, sought to determine why.

They analyzed British data on more than 223,500 UK Biobank participants whose health was tracked for an average of 12 years. Over that period, 3,313 women (1.5%) went on to develop rheumatoid arthritis.

Later onset of periods (having first period at age 14 rather than 13) was linked to a 17% higher risk for rheumatoid arthritis, as was an earlier start to menopause (before age 45).

Women who entered menopause before age 45 had a 46% higher risk for rheumatoid arthritis compared women who began menopause at 50 or 51, Pan's group found.

If a woman's "reproductive years" -- the time between her first period and when menopause began -- were 33 years or less, she faced a 39% higher risk for rheumatoid arthritis compared to women with more reproductive years, the team added.

Hysterectomy or oophorectomy (removal of the ovaries) also caused an uptick in risk.

Women who took birth control pills showed no increase in rheumatoid arthritis risk, although hormone replacement therapy use did up the odds by 46%.

Finally, women who bore four children had an 18% higher odds for the disease compared to women who had two kids, the research showed.

Pan's team stressed that the findings could not prove cause and effect, only associations.

"The findings of this study are significant and form a basis on which novel and target-specific intervention measures to curb the risk of [rheumatoid arthritis] in women may be developed," Pan's group said.

The findings were published Jan. 9 in the journal RMD Open.

More information

Find out more about rheumatoid arthritis at the Mayo Clinic.

SOURCE: BMJ, news release, Jan. 9, RMD Open, Jan. 9, 2024