Objective: Fat intake is generally thought as a risk factor for onset of ulcerative colitis (UC), while epidemiological data had been controversial. This study aimed to evaluate the role of fat intake in the development of UC.

Methods: Comprehensive search in PubMed and Embase was conducted to identify all relevant studies, and the role of fat intake in the development of UC was quantitatively assessed by dose-response meta-analysis.

Results: Nine studies (four case-control and five prospective cohort) were indentified with a total of 966 UC cases and 171 589 controls. No evidence of a nonlinear dose-response association was found between fat intake and UC risk. Overall, the summary relative risks (RR) for per 30 g increment/day were 1.023 (95%confidence interval [CI]: 0.963-1.087; I2  = 24%; n = 6) for total fat intake, 1.063 (95%CI: 0.845-1.337; I2  = 44.5%; n = 4) for saturated fat intake, 1.214 (95%CI: 0.911-1.618; I2  = 63.1%; n = 4) for monounsaturated fat (MUFA) intake, and 1.247 (95%CI: 0.948-1.640; I2  = 25.4%; n = 4) for polyunsaturated fat (PUFA) intake, respectively. Subgroup and sensitivity analyses showed inconsistent results on PUFA intake, which was significantly related with UC risk after adjusting for smoking (RR: 1.617, 95%CI: 1.045-2.502; I2  = 0%; n = 3). For PUFA and MUFA subtypes, no subtypes were significantly associated with UC risk (P > 0.05), and only docosahexaenoic acid showed a potential protective effect in the development of UC (RR for the highest versus lowest intake level: 0.642, 95%CI: 0.403-1.024; I2  = 34.4%; n = 3)

Conclusions: This meta-analysis suggested a lack of association between fat intake and UC risk, and large-scale prospective designed studies are warranted to confirm our findings.