Smoking Behaviour Changes After Diagnosis of Inflammatory Bowel Disease and Risk of All-cause Mortality

• Published in: Journal of Crohn's and colitis Vol. 16; no. 7; pp. 1030 - 1038
• Main Authors: Hua, Xinwei, Lopes, Emily W, Burke, Kristin E, Ananthakrishnan, Ashwin N, Richter, James M, Lo, Chun-Han, Lochhead, Paul, Chan, Andrew T, Khalili, Hamed
• Format: Journal Article
• Language: English
• Published: UK Oxford University Press 04-08-2022
• Subjects: Colitis, Ulcerative - diagnosis; Colitis, Ulcerative - epidemiology; Crohn Disease - diagnosis; Crohn Disease - epidemiology; Follow-Up Studies; Humans; Medicin och hälsovetenskap; Original; Prospective Studies; Risk Factors; Smoking - adverse effects; Smoking - epidemiology; Inflammatory bowel disease; mortality; behaviour change; smoking
• ISSN: 1873-9946; 1876-4479; 1876-4479
• DOI: 10.1093/ecco-jcc/jjac015

Abstract
Background and Aims
We examined smoking behaviour changes after diagnoses of Crohn’s disease [CD] and ulcerative colitis [UC] and evaluated their impact on mortality.
Methods
Study population included incident CD or UC cases from three cohorts of the Nurses’ Health Study [NHS], NHSII, and Health Professionals Follow-up Study. Smoking and other risk factors were prospectively assessed. Smoking behaviour changes were categorised as never, former [i.e., quit smoking before diagnosis], quitters [i.e., quit smoking after diagnosis], and current [i.e., continue smoking after diagnosis]. Follow-up for date and cause of death was completed through linkage to the National Death Index. Cox proportional hazard regression was used to estimate hazard ratios [HRs] and 95% confidence intervals [CIs].
Results
Among 909 eligible CD and UC cases, 45% were never smokers, 38% were past smokers, and 16% were active smokers at the time of diagnosis. Among active smokers, 70% of patients with CD and 44% of patients with UC continued to smoke after diagnosis. In patients with CD, compared with current smokers, the multivariable-adjusted HRs [95% CI] of death were 0.19 [0.10 to 0.38] for never smokers, 0.31 [0.16 to 0.57] for former smokers, and 0.41 [0.18 to 0.93] for quitters. Similarly for UC, compared with current smokers, we observed a reduced risk of mortality for never smokers [HR = 0.23, 95% CI 0.10 to 0.51], former smokers [HR = 0.23, 95% CI 0.11 to 0.48], and quitters [HR = 0.28, 95% CI 0.11 to 0.72].
Conclusions
In three cohorts of health professionals, a substantial proportion of patients with new diagnosis of CD and UC and history of smoking continued to smoke after diagnosis. Smoking cessation around the time of diagnosis was associated with a significant reduction in mortality.
Graphical Abstract