To Örebro University

BACKGROUND: To assess the relationship between diet quality and risk of older-onset Crohn's disease (CD) and ulcerative colitis (UC).

METHODS: We conducted a prospective cohort study of 83,147 participants from the Swedish Mammography Cohort and the Cohort of Swedish Men. We used food frequency questionnaire to calculate adherence scores to multiple derived health diet patterns: Alternate Healthy Eating Index (AHEI), Healthy Eating Index-2015 (HEI-2015), Healthful Plant-Based Diet Index (HPDI), and modified Mediterranean Diet Score (mMED) at baseline in 1997 in both cohorts. Diagnoses of CD and UC were retrieved from the Swedish Patient Register. We used Cox proportional hazards modeling to estimate the adjusted hazard ratios (HRs) and 95% CIs.

FINDINGS: Through December of 2017, we confirmed 164 incident cases of CD and 395 incident cases of UC. Comparing the highest to the lowest quartiles, the adjusted HRs of CD were 0.73 (95% CI, 0.48, 1.12, Ptrend = 0.123) for AHEI; 0.90 (0.57, 1.41, Ptrend = 0.736) for HEI 2015; 0.52 (95% CI 0.32, 0.85, Ptrend = 0.011) for HPDI; and 0.58 (95% CI 0.32, 1.06, Ptrend = 0.044) for mMED. In contrast, we did not observe an association between any diet quality score and risk of UC.

INTERPRETATION: We found that several healthy eating patterns were associated with a lower risk of older-onset CD. Our findings provide a rationale for adapting different healthy dietary patterns based on individuals' food preferences and traditions for designing future prevention strategies for IBD.