Early menopause—before the age of 45—taking hormone replacement therapy (HRT), and having 4 or more children are among several hormonal and reproductive factors linked to a heightened risk of rheumatoid arthritis in women, according to a long-term study of over 223,000 women.

Scientists have found long-term exposure to high levels of air pollution was associated with an approximately 40% higher risk of rheumatoid arthritis, a 20% higher risk of inflammatory bowel disease