Inflammatory bowel disease (IBD) encompasses many chronic gastrointestinal diseases, including Ulcerative Colitis (UC) and Crohn’s Disease (CD).1 Although the prevalence of IBD appears to be flattening in Western Europe and North America, at around 0.3%, limited data indicates that IBD is increasing in low and middle-income countries.2 In the Middle East and North Africa (MENA), the prevalence of IBD is largely unknown and data about possible risk factors of IBD are also scarce. However, findings, mostly pertaining to UC, from a few countries suggest a rising incidence of IBD in the region.3–5 Data related to CD are also scarce. There appears to be no published data on either UC or CD from Qatar.
CD and UC are multifactorial diseases whose causes are not completely understood. Research suggests that these diseases may result from the interplay between genetic susceptibility, innate and adaptive immunity, dysbiosis, and environmental factors.1 However, the contribution of each of these factors is still unknown. Some of the environmental factors that have been identified as risk factors for UC and CD include diet, UV exposure, stress, and smoking, although their contribution to disease risk differs between CD and UC.1 Recent research also suggests that the effects of some of these risk factors on the risk of UC and CD, especially smoking, may differ between populations6 and between genders.7
Tobacco smoking is one of the most researched risk factors for IBD development. Substantial research has shown that adulthood smoking is associated with a higher risk of CD.8–10 However, this association remains debatable as other studies have not found smoking to be a risk factor for CD development.11,12 For example, in a study of Ashkenazi Jews, a population with one of the highest prevalence rates of CD, smoking has not been shown to be a risk factor.12 Similarly, in Spain, no differences were observed in smoking exposure between CD cases and controls.11 These findings suggest that the effect of smoking on CD development may differ across populations. On the other hand, while only a few studies have been conducted, most findings point towards weak or no associations between childhood passive smoking and CD.8,13 To the best of our knowledge, research on the association between cigarette smoking and CD in Arab populations in the Middle East and North Africa are scarce.
