Abstract
BACKGROUND & AIMS: The study sought to investigate the association between socioeconomic status (SES) and risk of incident irritable bowel syndrome (IBS), and the mediating role of lifestyle factors.</p>
METHODS: Participants free of IBS at recruitment were included in this retrospective analysis of a prospectively collected cohort (N = 353,790). SES was assessed through household income, education, and employment status, with different patterns identified through latent class analysis. Healthy lifestyle score was calculated including never smoking, moderate alcohol consumption, healthy diet, regular physical activity, normal body mass index, and healthy sleep duration. The primary endpoint was incident IBS. A Cox proportional hazards model with sequential mediation analysis was used to estimate the association and mediation effect.</p>
RESULTS: During a median follow-up of 14.5 years, 7240 (2.1%) incident IBS cases were identified. Overall, 94,660 (26.7%), 186,317 (52.7%), and 72,813 (20.6%) participants were classified into low, medium, and high SES patterns, respectively. A high SES pattern was associated with lower IBS risk vs a low SES pattern (hazard ratio, 0.61; 95% confidence interval, 0.57-0.66), with 10.2% of effect mediated by a healthy lifestyle score. Similar findings were observed for SES scores. Regarding individual SES items, higher household income and education and employed status were linked to 8%-32% lower IBS risk, with 5.6%-20.8% of mediation proportions. Notably, individuals with high SES pattern and healthy lifestyle score of 5 or 6 had a 55% (hazard ratio, 0.45; 95% confidence interval, 0.39-0.51) reduced IBS risk vs those with a low SES pattern and healthy lifestyle score of 0-2.</p>
CONCLUSIONS: Higher SES is associated with reduced risk of incident IBS with mediation effect of healthy lifestyle factors. Interventions targeting both SES inequalities and lifestyle improvements may help reduce IBS burden.</p>