Cigarettes & colorectal neoplasia in IBD

Cigarettes & colorectal neoplasia in IBD

August 23, 2022

Issue 16

Clinical Question

What is the impact of cigarette smoking on colorectal neoplasia risk in IBD?

Editor’s Bottom Line

Cigarette smoking is associated with a small but significant increase in colorectal neoplasia among patients with IBD. Whether this relationship is causal, or reflective of other confounding factors related to lifestyle or disease activity remains to be proven.


van der Sloot KWJ, Tiems JL, Visschedijk MC, et al. Cigarette Smoke Increases Risk for Colorectal Neoplasia in Inflammatory Bowel Disease. Clin Gastroenterol Hepatol. 2022;20(4):798–805.e1.


Researchers at the University Medical Center Groningen in the Netherlands, retrospectively analyzed a cohort of 1,326 IBD patients followed for an average of 11–14 years. They analyzed biopsies taken during the study period and found that 8.6% of Crohn’s disease (CD) patients and 15.1% of ulcerative colitis (UC) patients developed colorectal neoplasia. Pathology reports showed that 7.2% of all participants with neoplasia had colorectal carcinoma, 7.8% had high-grade dysplasia, and 85% had low-grade dysplasia. Most neoplastic lesions were unifocal and polypoidal and in 59.5% of cases there was a documented history of inflammation at the site of the neoplasia.

Those with CD and colorectal neoplasia were a mean 48.7 years of age at baseline, compared to 40.3 years of age for CD patients without neoplasia. UC patients with neoplasia were a mean 51.7 years of age at baseline, compared to 42.8 years of age for those without neoplasia.

Multivariate analyses revealed several significant predictors of colorectal neoplasia in CD patients, namely a history of colorectal neoplasia in a first-degree relative (adjusted Odds Ratio [aOR]: 3.55; 95% Confidence Interval [CI], 1.58–7.96; p=0.002), high risk status for neoplasia according to the European Crohn’s and Colitis Organisation guidelines (aOR: 2.97; 95% CI, 1.35–6.52; p=0.007), and both active smoking and passive smoke exposure (aOR: 2.2 for active smoking; 95% CI, 1.02–4.75; p=0.044 and aOR: 1.87 for current passive smoke exposure; 95% CI, 1.09–3.20; p=0.024 and aOR: 4.79 for childhood passive smoke exposure; 95% CI, 1.72–13.34; p=0.003).  

In contrast, the only variable found to increase colorectal neoplasia risk in the UC population in the multivariate analysis was former smoking (aHR: 1.73; 95% CI, 1.05–2.85; p=0.032).


Study Design: Retrospective cohort analysis

Funding: None

Allocation: Not applicable

Setting: Single center

Level of Evidence: 2b