A RECENT study has explored the complex relationship between smoking and ulcerative colitis (UC), shedding light on how smoking may influence both the risk of developing UC and its severity in existing cases. Despite the known risks of smoking to general health, prior research has suggested that it may have a protective effect in the context of UC. This study aimed to clarify this relationship by analysing data from case-control studies, exploring the protective impact of smoking in comparison to non-smoking and smoking cessation. The key finding was that smoking may offer a protective effect against UC onset.
To examine the potential role of smoking in UC, the researchers conducted a meta-analysis of nine case-control studies sourced from multiple databases, including PubMed, Embase, and Scopus. The studies investigated the association between smoking and UC progression, providing insight into how smoking might influence both the incidence of the disease and the therapeutic outcomes. Statistical analysis was used to calculate pooled odds ratios and confidence intervals, helping to assess the strength of the relationships observed. The study also accounted for heterogeneity, ensuring that findings were robust despite varying study designs and population characteristics.
The results highlight a nuanced connection between smoking and UC, with observations indicating that smoking may not only reduce the risk of developing UC, but also alleviate its severity for those already diagnosed. Specifically, the pooled odds ratio (OR) for smoking compared to non-smoking was 0.48 (95% CI: 0.40–0.56), revealing a significant protective effect against UC onset. Furthermore, smoking appeared more protective than smoking cessation, with an OR of 0.26 (95% CI 0.21–0.32).
While these findings are intriguing, the study does have limitations. The reliance on case-control studies, which can be susceptible to recall bias, and the inclusion of only a small number of studies mean that further research is necessary to confirm these findings and explore the underlying mechanisms. Clinically, these results may encourage a deeper investigation into smoking’s role in UC management, but smoking cessation remains a critical priority for overall health.
Reference
Mi Y et al. Relationship between smoking status and ulcerative colitis: a meta-analysis based on a case–control study. Sci Rep. 2025;17(1):13329
