Isotretinoin Use and the Risk of Inflammatory Bowel Disease: A Population-Based Cohort Study

Limited evidence suggests that isotretinoin may be associated with inflammatory bowel disease (IBD). To explore this association, we conducted a retrospective population-based cohort study in British Columbia, Canada, among participants who were newly treated with isotretinoin or topical acne medications. The entire population of untreated provincial residents aged 12–29 years served as the reference group. During the 12-year study period, we identified 46,922 participants treated with isotretinoin, 184,824 treated with a topical acne medication, and 1,526,946 untreated individuals. Compared with untreated individuals, we observed no significant association between isotretinoin use and IBD (rate ratio (RR) 1.14; 95% confidence interval (CI) 0.92–1.41). As expected, we found no association with topical acne medications (RR 1.11; 95% CI 0.99–1.24). In prespecified secondary analyses, isotretinoin was associated with IBD among individuals aged 12–19 years (RR 1.39; 95% CI 1.03–1.87) and topical acne medications were associated with ulcerative colitis (RR 1.19; 95% CI 1.00–1.42). Our primary analyses found no association between isotretinoin and IBD. In prespecified secondary analyses, some evidence was found of associations with isotretinoin as well as topical acne medications, suggesting a possible association between IBD and acne itself. Additional research is needed to explore this possibility.