Long‐Term Risk of Inflammatory Bowel Disease With MASLD: A Large‐Scale Prospective Cohort Study in UK Biobank

ABSTRACT Background Similar worsening epidemics globally have been showed in newly coined metabolic dysfunction‐associated steatotic liver disease (MASLD) and inflammatory bowel disease (IBD). We aimed to investigate the prospective association of MASLD, MASLD types, and cardiometabolic risk factors (CMRFs) with long‐term risk of incident IBD in a large‐scale population cohort. Methods Participants free of IBD at enrollment from UK Biobank were included. Baseline MASLD was measured by fatty liver index together with at least one CMRF, based on the latest AASLD/EASL criteria. MASLD type was classified as pure MASLD and MetALD (MASLD with increased alcohol intake). Primary outcome was incident IBD, including ulcerative colitis (UC) and Crohn's disease (CD). Multivariable Cox regression was conducted to examine the related associations. Results Overall, 403 520 participants (aged 56.2 ± 8.1 years, 45.6% males) were included. Of whom, 151 578 (37.6%) were considered as MASLD at baseline. During a median of 13.0 years' follow‐up, 2398 IBD cases were identified. Compared with normal population, individuals with MASLD showed significant higher associations of incident IBD (HR = 1.39, 95% CI: 1.21–1.60), UC (HR = 1.34, 95% CI: 1.13–1.58), and CD (HR = 1.51, 95% CI: 1.20–1.89). Meanwhile, results were consistent when assessing pure MASLD (HR = 1.43, 95% CI: 1.23–1.66) and MetALD (HR = 1.46, 95% CI: 1.15–1.86). The excess risk of incident IBD was more evident with the increase of CMRFs numbers ( p trend < 0.001). Conclusion MASLD, either pure MASLD or MetALD, and a combination of different CMRFs are all associated with increased risk of IBD, including both UC and CD. Additionally, there is greater risk of incident IBD as the number of CMRFs increase.