Risk factors for ulcerative colitis in a Chinese population: an age-matched and sex-matched case-control study

Cigarette smoking, alcohol use, appendectomy, and family history of inflammatory bowel disease (IBD) have all been shown to be associated with IBD, but there were no reports of risk factors for IBD in a Chinese population in which the incidence of IBD is increasing during the past decade. We conducted a case-control study to examine associations between previously reported environmental risk factors and development of ulcerative colitis (UC) in Wuhan city, central China.

A total of 177 patients with UC and 177 age-matched and sex-matched controls were prospectively studied in Wuhan city from January 2004 to December 2004. An age-matched and sex-matched case-control study was conducted to assess the role of smoking, alcohol use, appendectomy, and other potential risk factors in the development of UC by a detailed questionnaire.

Smoking was a protective factor and exsmoking is a risk factor for UC [compared with nonsmokers, smokers: odds ratios (OR)=0.28, 95% confidence intervals (CI): 0.16-0.48, P=0.0001; exsmokers: OR=4.36, 95%CI: 1.46-13.04, P=0.008]. Positive family history of IBD was a risk factor (OR=4.35, 95%CI: 1.21-15.71, P=0.025) whereas appendectomy was a protective factor (OR=0.24, 95%CI: 0.07-0.86, P=0.028) for UC. There were no significant associations between UC and other factors examined.

Although the incidence of UC in Chinese is relatively lower than that in white, the same risk factors for UC that were reported in white populations were associated with Chinese UC patients. Specifically, smoking was a protective factor for UC and exsmoking was associated with an increase risk of UC in a Chinese population. Family history of IBD was shown to be a risk for UC, whereas appendectomy was associated with a low risk for UC.