Chronic diarrhea was linked with a higher risk of developing rheumatoid arthritis (RA), especially among ever-smokers, in a French cohort of more than 65,000 women.
The prospective cohort was part of a cancer and nutrition study that began in 1990. During the study, participants answered questionnaires about their lifestyle and health. The third questionnaire, mailed in 1993, assessed gastrointestinal (GI) disorders.
A total of 530 validated incident cases of RA among 65,424 women occurred after a mean 11.7 years after study baseline, the researchers reported.
Compared with not having a GI disorder, having chronic diarrhea was associated with an increased risk of subsequent RA independent of dysthyroidism or dietary habits. The study reported a hazard ratio of 1.7 (95% confidence interval [CI] 1.13, 2.58). Among women identified as ever-smokers, the hazard ratio was even higher: 2.21 (95% CI 1.32, 3.70).
The study found no link between constipation, or alternating diarrhea and constipation, with a heightened risk of RA development.
“These data fit with the mucosal origin hypothesis of rheumatoid arthritis, where interaction between intestinal dysbiosis and smoking could occur at an early stage to promote emergence of autoimmunity, followed years later by clinical disease,” the researchers wrote.
Nguyen Y, Mariette X, Salliot C, Gusto G, Boutron-Ruault MC, Seror R. Chronic diarrhoea and risk of rheumatoid arthritis: findings from the French E3N-EPIC Cohort Study. Rheumatology. 2020;59(12):3767-3775. doi:10.1093/rheumatology/keaa133