Rising Incidence of Inflammatory Bowel Disease in South Asian Children in New Zealand—A Retrospective Population-Based Study

Abstract

Objectives: High rates of inflammatory bowel disease (IBD) are reported in children of South Asian (SA) descent in some western countries. This population-based study describes the incidence and clinical course of IBD in SA children compared to non-South Asian (NSA) children in New Zealand (NZ). Methods: Children (≤15 years) with new-onset IBD presenting to a centralized tertiary referral center in Auckland, NZ from 2010 to 2020 were identified. Disease phenotype, clinical characteristics, response to exclusive enteral nutrition, clinical remission rates at 3 and 12 months, biologic use, corticosteroid exposure, and disease complications were compared by ethnicity; IBD incidence was calculated. Results: There were 127 (26 SA; 101 NSA) children with Crohn disease, 41 (10 SA; 31 NSA) with ulcerative colitis, and 10 (3 SA; 7 NSA) with IBD-unclassified. IBD incidence in SA and NSA children was 14.1 per 100,000 and 4.3 per 100,000 respectively (P < 0.001). IBD incidence increased by 5.6% per year (P = 0.022), due to a greater rise in incidence in SA (SA 16.8% per year, P = 0.015; NSA 4.5% per year, P = 0.317). At presentation, SA children had worse biochemical parameters, severe colitis, and vitamin D deficiency. SA children had lower rates of remission following exclusive enteral nutrition (28.5% vs 65.0%, P < 0.001) or biologic induction (35.7% vs 70.8%, P = 0.020), at 3-month (35.3% vs 69.8%, P < 0.001) and 12-month follow-up (29.4% vs 55.0%, P = 0.005). No significant differences were found in disease location or corticosteroid burden. Conclusions: Increasing incidence of IBD was disproportionately represented by SA children with more severe disease and lower remission rates following exclusive enteral nutrition or biologic therapy.