Smoking was associated with increased complication rates in Crohn's disease but linked to lower complication rates and higher remission in ulcerative colitis, according to a recent study.
The retrospective cohort study, published in Frontiers in Gastroenterology, analyzed data from 2016-2022 of 373 IBD patients, including 209 with Chron's disease and 164 with ulcerative colitis. Patients were aged over 18 years and excluded if they had a history of cancer (other than colon cancer) or other gastrointestinal disorders. The study assessed smoking habits, complications, and remission rates.
Among the Chron's disease patients, 43.7% were nonsmokers, 33% were smokers, and 23.3% were secondary smokers. Chron's disease complications were observed in 53.6% of patients, with higher rates among smokers (62.6%) and secondary smokers (77.7%) compared to nonsmokers (56.6%).
In ulcerative colitis, smoking was associated with lower complication rates, with smokers showing a complication rate of 21.4% compared to 55% in nonsmokers. Additionally, smoking duration had a significant impact on complications, with fewer complications observed in those smoking for 1 to 5 years compared to those with longer smoking histories. There were 44 nonsmokers, 9 smokers, and 13 secondary smokers in the group.
"Smoking’s protective effect against ulcerative colitis has been extensively studied, although the precise mechanisms remain incompletely understood. One proposed mechanism involves the immunomodulatory effects of nicotine, a key component of tobacco smoke," wrote study investigators. "However, it is important to note that the impact of smoking on ulcerative colitis remission is still a topic of debate. While some studies have observed a positive association, others have reported conflicting or even negative findings."
Limitations included retrospective design and single-center focus, noted investigators.
They reported no conflicts of interest.