Table 1.

PECOS criteria for inclusion of studies.

Parameter	Criterion
Population	Ulcerative colitis patients diagnosed by specific criteria
Exposure	Varying levels of red meat or processed meat consumption
Comparison	Comparison of levels/different amounts of red meat or processed meat consumption
Outcomes	The occurrence risk of ulcerative colitis The recurrence risk of ulcerative colitis
Study design	Cohort study, case–control study