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Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.

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Ulcerative colitis epidemiology and demographics

Introduction

Overview

Overview

Ulcerative colitis (UC) is most common in early-industrialized regions such as North America, Northern and Western Europe, and Oceania. In these regions incidence has stabilized or declined since 1990, while prevalence continues to rise.[1][2] Incidence is now rising rapidly in newly industrialized countries of Asia, Latin America, and the Middle East. UC therefore can no longer be regarded as a disease confined to Western populations.[3] In the United States, UC prevalence is approximately 378 per 100,000 population, or about 1.25 million people.[4] UC is most often diagnosed in the second to fourth decades of life, but elderly-onset disease accounts for a growing share of new diagnoses. There is no consistent sex predominance.[5]

Epidemiology and Demographics

Epidemiology and Demographics

Global distribution and epidemiologic stages

The older description of a static north–south gradient, with identical worldwide distribution of UC and Crohn’s disease, has been replaced by a model of four epidemiologic stages through which regions move as they industrialize.[2] These stages have now been quantified using 522 population-based studies from 82 regions covering 1920–2024.[3]

Epidemiologic stages of inflammatory bowel disease
Stage Incidence and prevalence pattern Representative regions
1. Emergence Low incidence and low prevalence Developing countries
2. Acceleration in incidence Incidence rising rapidly; prevalence still low Newly industrialized countries in Asia, the Middle East, and Latin America
3. Compounding prevalence Incidence slowing, plateauing, or declining; prevalence rising steadily North America, Western Europe, Oceania
4. Prevalence equilibrium Prevalence plateaus as deaths in an aging IBD population balance new diagnoses Not yet observed; modeled for several high-income regions by about 2045[3]

Incidence

  • Early-industrialized regions: Since 1990, most population-based studies from North America and Europe report stable or declining UC incidence.[1] The highest UC incidence rates worldwide are reported from Northern Europe, particularly Scandinavia.[1][6]
  • United States: The age- and sex-standardized incidence of IBD is 10.9 per 100,000 person-years.[4] In a US employment-based claims cohort, UC incidence did not change between 2010 and 2019.[7]
  • Newly industrialized regions: Incidence is rising sharply. For example, UC incidence in Brazil had an average annual percentage change of +14.9% from 1988 to 2012.[1] In transitioning regions, UC incidence typically rises before Crohn’s disease incidence.[2] UC incidence in Japan has increased steadily since the 1960s.[7]
  • Children: Incidence of pediatric-onset IBD continues to rise.[8]

Prevalence

  • The highest prevalence is reported in Europe, reaching about 505 per 100,000 in Norway, and in North America.[1]
  • UC prevalence in North America exceeds 400 per 100,000.[6]
  • United States: A pooled, insurance-standardized analysis of 4 administrative datasets estimated UC prevalence at 378 per 100,000 (about 1.25 million Americans). Overall IBD prevalence was 721 per 100,000.[4]
  • Japan and the United States: In employment-based claims data from 2010 to 2019, UC prevalence rose in both countries. In the US it rose from 158 to 233 per 100,000; in Japan it reached an age-standardized 98 per 100,000 by 2019.[7]
  • Trajectory: UC begins early in life and carries low mortality, so prevalence keeps compounding in high-income regions. Prevalence equilibrium is projected there by about 2045, while incidence continues to rise in Asia, Africa, and Latin America.[3]

Age

  • UC can present at any age. It is most commonly diagnosed in the second to fourth decades, with peak onset at about 30–40 years.[5][9]
  • In US data, IBD incidence peaks in the third decade of life. It then stays at a lower, relatively stable level through the fourth to eighth decades, with no discrete second peak.[4]
  • Elderly-onset UC: Patients older than 60 years account for up to 20% of new UC diagnoses. This share is growing with population aging and complicates management because of comorbidity and polypharmacy.[5]

Sex

  • Men and women are affected roughly equally. Some adult series show a slight male predominance.[5]
  • The sex ratio varies by population. Men predominate among patients with UC in Japan, whereas women slightly predominate in a US employment-based cohort.[7]

Race, ethnicity, and migration

  • In the United States, IBD prevalence is 812 per 100,000 in White, 504 in Black, 458 in Hispanic, and 403 in Asian Americans. IBD is therefore less often diagnosed in Black, Asian, and Hispanic Americans, though it still occurs in substantial numbers.[4]
  • People of Ashkenazi Jewish ancestry have a 2- to 5-fold higher risk of UC.[10][11] Ethnic differences in IBD risk have diminished over time, which points to environmental contributions.[12]
  • Migration: Children of migrants who move from low- to high-incidence countries develop IBD risk approaching that of the host population. This supports a strong gene–environment interaction.[12][9]
  • For genetic, environmental, and lifestyle determinants of UC, see Ulcerative colitis risk factors.
References

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Ng SC, Shi HY, Hamidi N, Underwood FE, Tang W, Benchimol EI; et al. (2017). “Worldwide incidence and prevalence of inflammatory bowel disease in the 21st century: a systematic review of population-based studies”. Lancet. 390 (10114): 2769–2778. doi:10.1016/S0140-6736(17)32448-0. PMID 29050646.
  2. ↑ 2.0 2.1 2.2 Kaplan GG, Windsor JW (2021). “The four epidemiological stages in the global evolution of inflammatory bowel disease”. Nat Rev Gastroenterol Hepatol. 18 (1): 56–66. doi:10.1038/s41575-020-00360-x. PMID 33033392 Check |pmid= value (help).
  3. ↑ 3.0 3.1 3.2 3.3 Hracs L, Windsor JW, Gorospe J, Cummings M, Coward S; et al. (2025). “Global evolution of inflammatory bowel disease across epidemiologic stages”. Nature. 642 (8067): 458–466. doi:10.1038/s41586-025-08940-0. PMID 40307548 Check |pmid= value (help).
  4. ↑ 4.0 4.1 4.2 4.3 4.4 Lewis JD, Parlett LE, Jonsson Funk ML, Brensinger C, Pate V, Wu Q; et al. (2023). “Incidence, prevalence, and racial and ethnic distribution of inflammatory bowel disease in the United States”. Gastroenterology. 165 (5): 1197–1205.e2. doi:10.1053/j.gastro.2023.07.003. PMID 37481117 Check |pmid= value (help).
  5. ↑ 5.0 5.1 5.2 5.3 Le Berre C, Honap S, Peyrin-Biroulet L (2023). “Ulcerative colitis”. Lancet. 402 (10401): 571–584. doi:10.1016/S0140-6736(23)00966-2.
  6. ↑ 6.0 6.1 Gros B, Kaplan GG (2023). “Ulcerative colitis in adults: a review”. JAMA. 330 (10): 951–965. doi:10.1001/jama.2023.15389. PMID 37698559 Check |pmid= value (help).
  7. ↑ 7.0 7.1 7.2 7.3 Yamazaki M, Chung H, Xu Y, Qiu H (2023). “Trends in the prevalence and incidence of ulcerative colitis in Japan and the US”. Int J Colorectal Dis. 38 (1): 135. doi:10.1007/s00384-023-04417-6. PMC PMC10198866 Check |pmc= value (help).
  8. ↑ Bouhuys M, Lexmond WS, van Rheenen PF (2023). “Pediatric inflammatory bowel disease”. Pediatrics. 151 (1): e2022058037. doi:10.1542/peds.2022-058037.
  9. ↑ 9.0 9.1 Ungaro R, Mehandru S, Allen PB, Peyrin-Biroulet L, Colombel JF (2017). “Ulcerative colitis”. Lancet. 389 (10080): 1756–1770. doi:10.1016/S0140-6736(16)32126-2. PMID 27914657.
  10. ↑ Ordás I, Eckmann L, Talamini M, Baumgart DC, Sandborn WJ (2012). “Ulcerative colitis”. Lancet. 380 (9853): 1606–1619. doi:10.1016/S0140-6736(12)60150-0. PMID 22914296.
  11. ↑ Wu Y, Gettler K, Kars ME, Giri M, Li D, Bayrak CS; et al. (2023). “Identifying high-impact variants and genes in exomes of Ashkenazi Jewish inflammatory bowel disease patients”. Nat Commun. 14 (1): 2256. doi:10.1038/s41467-023-37849-3. PMID 37080976 Check |pmid= value (help).
  12. ↑ 12.0 12.1 Cosnes J, Gower-Rousseau C, Seksik P, Cortot A (2011). “Epidemiology and natural history of inflammatory bowel diseases”. Gastroenterology. 140 (6): 1785–1794. doi:10.1053/j.gastro.2011.01.055. PMID 21530745.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Fahad Hasan, M.D.[2] Usama Talib, BSc, MD [3]