Cigarette smoking and passive smoke exposure was found to be linked to an increased risk of developing colorectal neoplasia (CRN) in patients with inflammatory bowel disease (IBD), according to the results of a study published in Clinical Gastroenterology and Hepatology.

A team of investigators from the University Medical Center Groningen conducted a retrospective cohort study in which they evaluated 1386 patients with IBD, with prior biopsy specimens examined and recorded in the Dutch nationwide pathology registry (PALGA), for the development of CRN. They based assessments of the study group population on clinical factors and history of active and passive cigarette smoke exposure. The researchers used Cox regression modeling to estimate active and passive cigarette smoke exposure and its subsequent effect according to the current risk stratification for prediction of CRN.

The investigators discovered that 153 (11.5%) patients developed CRN, comprising 11 (7.2%) colorectal carcinoma, 12 (7.8%) high-grade dysplasia, and 130 (85%) low-grade dysplasia diagnoses. For Crohn disease (CD), active smoking (hazard ratio [ HR] 2.2; 95% CI, 1.02-4.75) and passive smoke exposure (HR 1.87; 95% CI, 1.09-3.2) were found to be associated with a significantly increased risk for CRN. For ulcerative colitis (UC), former smoking increased the risk for CRN (HR 1.73; 95% CI, 1.05-2.85), but passive smoke exposure had no effect.


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This study was limited by the inclusion of data from a single tertiary IBD clinic, lack of cigarette smoke exposure details, and a relatively small sized study population. Nevertheless, the researchers determined that active and passive cigarette smoke is linked to the development of CRN in patients with CD and that former active smoking increases the risk for CRN in patients with UC. These findings suggest that individuals with IBD, especially CD, can decrease their risk for CRN through smoking cessation efforts and by avoiding exposure to cigarette smoke.

The authors concluded that “this study is the first to describe the important role of cigarette smoke in CRN development in IBD patients. Adding this risk factor improves the current risk stratification for CRN surveillance strategies.”

Reference

van deer Sloot KWJ, Tiems JL, Visschedijk MC, et al. Cigarette smoke increases risk for colorectal neoplasia in inflammatory bowel disease. Clin Gastroenterol Hepatol. Published online January 13, 2021. doi:10.1016/j.cgh.2021.01.015