Risk Factors for Crohns Disease

Risk factors for Crohn's Disease include smoking, lefthandedness, adult appendectomy, and use of oral contraceptives, nonsteroidal anti-inflammatory drugs (NSAIDs), and antibiotics; demographics also affect the risk for Crohns Disease.

Geographical, economical, educational, and occupational status can impact the risk. Crohns disease is more prevalent in developed countries and is more common in white-collar workers and individuals with indoor, sedentary occupations.³ It has been theorized that those with sedentary jobs have delayed intestinal transit time, resulting in increased contact between food antigens and the intestinal mucosa.

Several clinical and case-control studies have determined smoking increases the risk of developing Crohn Disease, and contributes to earlier disease onset, site of the disease, rate of relapse after surgery, and disease severity.^4-6 Two studies demonstrate an association between childhood second-hand smoke exposure and increased risk for developing Crohn's Disease.^7,8

Previous antibiotic use appears to be a risk factor for Crohns Disease. A case-control study of 302 young Crohns Disease patients (< 25 years) compared to matched controls investigated childhood risk factors for development of the disease. Crohn's Disease patients reported more frequent use of antibiotics in childhood and more frequent upper respiratory infections than control patients. Other factors that appeared to increase disease risk were history of eczema and consumption of a low fiber diet.⁹ Another study demonstrated a higher frequency of childhood infections, specifically pharyngitis, as well as more frequent use of antibiotics for otitis media and pharyngitis, in Crohn's Disease patients compared to controls.¹⁰ Utilizing the United Kingdom's General Practice Research Database, researchers at Queen's Medical Centre in Nottingham, England, found a statistically significant association between Crohns disease and prior antibiotic use in 587 Crohn's Disease cases and 1,460 controls.¹¹

Women taking oral contraceptives have twice the risk of developing Crohns Disease.¹² Use of low dose oral contraceptives does not appear to significantly influence the activity or course of the disease, although contraceptives compound the risk of thromboembolic events, which is already high due to hypercoagulation characteristic of Crohn's Disease.¹³ There is also some evidence of NSAID induced Crohn’s disease in the small and large bowel.^14-16

Other factors that may increase the risk of developing Crohn’s disease are appendectomy in adulthood^17,18 and left-handedness, with lefthanded individuals having twice the risk of righthanded persons.^19,20



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