Trends in Inflammatory Bowel Diseases Across a Eurasian Crossroad: A Decade of Multicenter Data

Abstract

Background: The incidence of inflammatory bowel disease (IBD) is rising in newly industrialized nations, yet nationally representative data from Türkiye are limited. We characterized recent epidemiologic trends, clinical features, and geographic distribution of newly diagnosed IBD across Türkiye.

Methods: This retrospective multicenter cohort included adults (≥18 y) with newly diagnosed IBD at 24 gastroenterology centers spanning all 7 Turkish regions (2010-2022). Demographics, disease behavior/extent, smoking status, family history, and province of residence were collected. Temporal and regional patterns were analyzed using χ2 tests and segmented regression.

Results: Among 3463 patients, 51.1% had UC, 44.0% CD, and 0.7% IC. Males comprised 57.7%; median age at diagnosis was 30 years for CD and 32 years for UC. Annual IBD diagnoses more than doubled from 2010 to 2021. The UC-to-CD ratio increased from 0.94:1 (2010-2016) to 1.29:1 (2016-2022, P < 0.001). CD most often showed inflammatory behavior (55.5%) and ileocolonic involvement (37.1%); UC frequently presented as pancolitis (39.3%). Smoking (24.2% vs 10.9%) and family history (6.8% vs 4.5%) were more common in CD than UC (both P <0.01). Choropleth mapping revealed a west-to-east gradient, with Marmara and Aegean regions bearing the highest burden. Multivariable analysis showed UC diagnosis was independently associated with state-hospital care, residence in Central Anatolia or the Black Sea, and age ≥60 years.

Conclusion: Incident IBD in Türkiye has risen steadily, with UC now exceeding CD. Patients predominantly present in early adulthood. Regional and hospital-level differences highlight the need for a national registry and targeted resource allocation.

Keywords: Crohn’s disease; Türkiye; epidemiology; inflammatory bowel disease; ulcerative colitis.