The association between race and Crohn's disease phenotype in the Western Cape population of South Africa, defined by the Montreal Classification System.

Abigail Basson,Mikateko Mazinu,Gillian Watermeyer,Esme Jordaan,Rina Swart,Benoit Foligne

doi:10.1371/journal.pone.0104859

Abstract

BackgroundInter-racial differences in disease characteristics and in the management of Crohn's disease (CD) have been described in African American and Asian subjects, however for the racial groups in South Africa, no such recent literature exists.MethodsA cross sectional study of all consecutive CD patients seen at 2 large inflammatory bowel disease (IBD) referral centers in the Western Cape, South Africa between September 2011 and January 2013 was performed. Numerous demographic and clinical variables at diagnosis and date of study enrolment were identified using an investigator administered questionnaire as well as clinical examination and patient case notes. Using predefined definitions, disease behavior was stratified as ‘complicated’ or ‘uncomplicated’.ResultsOne hundred and ninety four CD subjects were identified; 35 (18%) were white, 152 (78%) were Cape Coloured and 7(4%) were black. On multiple logistic regression analysis Cape Coloureds were significantly more likely to develop ‘complicated’ CD (60% vs. 9%, p = 0.023) during the disease course when compared to white subjects. In addition, significantly more white subjects had successfully discontinued cigarette smoking at study enrolment (31% vs. 7% reduction, p = 0.02). No additional inter-racial differences were found. A low proportion of IBD family history was observed among the non-white subjects.ConclusionsCape Coloured patients were significantly more likely to develop ‘complicated’ CD over time when compared to whites.

Highlights

A subtype of inflammatory bowel disease (IBD), Crohn’s disease (CD) is believed to result from a complex interplay between genetic susceptibility and one or more environmental triggers
The majority of subjects in all racial groups were born in South Africa (95%), but individually, 100% of the Cape Coloureds compared to 77% of the white subjects, were born in South Africa (p,0.001)
There was no significant difference in the level of education between the white and Cape Coloured subjects, there was a significant difference in the median age at study enrolment [52.0 (IQR 40.0–67.5) years vs. 46.0 (IQR 38.0– 55.5) years, respectively] as whites were on average six years older at study enrolment (p = 0.04)

Summary

Introduction

A subtype of inflammatory bowel disease (IBD), Crohn’s disease (CD) is believed to result from a complex interplay between genetic susceptibility and one or more environmental triggers. Disease presentation and severity are known to vary between individuals, having important implications for disease management [1,2]. In recent years, issues of CD sub-classification by phenotype have been reviewed, and the Montreal classification system [2] (revised Vienna) is the accepted standard. Crohn’s disease is found in all racial groups worldwide. The majority of reports contributing to our understanding of disease presentation and clinical course originate primarily from Western populations, leaving a paucity of literature regarding the racial variability of CD phenotype [5,12,13,14]. Inter-racial differences in disease characteristics and in the management of Crohn’s disease (CD) have been described in African American and Asian subjects, for the racial groups in South Africa, no such recent literature exists

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