Fig. 2.

The prevalence of Crohn’s disease outcomes among current and former smokers at diagnosis compared with never smokers, by country of recruitment. The reference for the current and former smoker groups consisted of never-smoking Crohn’s disease cases (China: N = 94; USA: N = 135). Odds ratios were adjusted for sex, age at diagnosis, family history of IBD, and duration of disease at questionnaire. All outcomes were based on patient self-report at the time of the questionnaire. India not shown due to limited number of outcomes