Influence of socioeconomic development on incidence and disease phenotype in inflammatory bowel disease: a population-based incident study across 16 regions.

INTRODUCTION

The global rise in inflammatory bowel disease (IBD) parallels socio-economic development, but its influence on disease epidemiology and phenotype remains unclear. We aimed to characterise IBD incidence, clinical features, and associations with socio-economic indices across newly industrialised countries.

METHODS

This prospective population-based study spanned 16 regions in Africa, Asia, Latin America, and the Middle East from October 2021 for one year. Poisson regression estimated incidence rate ratios (IRR) for Human Development Index (HDI), Socio-demographic Index (SDI), subnational HDI, and urban population percentage. Mixed-effects models examined associations with disease phenotype, activity, and treatment.

RESULTS

Of 606 incident cases (229 Crohn's disease [CD], 348 ulcerative colitis [UC], 29 IBD-unclassified), incidence varied widely. Hong Kong had the highest crude annual incidence (IBD 7.43; CD 2.69; UC 3.44) and Vietnam the lowest (0.13; 0.04; 0.08). Urban population (per 10% increase) was associated with higher incidence of IBD (IRR 1.68), CD (1.73), and UC (1.62). HDI and SDI significantly correlated with CD (IRR 4.05 and 2.96, respectively), but not subnational HDI. Higher HDI and subnational HDI were associated with increased odds of perianal CD (adjusted OR 2.61 and 2.40). Other disease phenotype, activity, and treatment pattern were not significantly linked to any index.

CONCLUSION

Higher urbanisation and development are associated with higher IBD incidence, particularly CD, but not with disease activity at diagnosis. Notably, perianal CD was more common in regions with higher HDI and subnational HDI, suggesting an association with regional socioeconomic development. These highlight the need for region-specific early diagnosis strategies.