Chronic diarrhoea factors in subsequent development of rheumatoid arthritis

Women with chronic diarrhoea are likely to develop rheumatoid arthritis (RA), especially those who are current or previous smokers, a study reports.

The study used data from a French prospective cohort including 98,995 healthy women, among whom 65,424 were included in the analysis. All participants completed questionnaires inquiring about their lifestyles and health. Gastrointestinal transit was recorded at the third questionnaire (Q3) sent in 1993.

At Q3, usual gastrointestinal transit was normal in 46,598 (71.2 percent) women, diarrhoea in 1,835 (2.8 percent), constipation in 9,173 (14 percent), and alternating diarrhoea and constipation in 7,818 (12 percent). There were 530 women who developed RA after a mean of 11.7 years following Q3. Mean age at RA diagnosis was 65.2 years. A total of 162 women had seropositive RA.

Cox proportional hazards regression models, with age as the time scale, showed that chronic diarrhoea was associated with an increased risk of developing RA during follow-up (hazard ratio [HR], 1.70, 95 percent confidence interval [CI], 1.13–2.58), irrespective of dysthyroidism or dietary habits. This association was more pronounced among ever-smokers (HR, 2.21, 95 percent CI, 1.32–3.70).

Neither constipation nor alternating diarrhoea/constipation was linked to RA risk.

The present data are in line with the mucosal origin hypothesis of RA, where interaction between intestinal dysbiosis and smoking could occur at an early stage to promote autoimmunity, followed years later by clinical disease, according to researchers.