Table 3. Study quality risk bias assessment for cohort studies.

Study ID	Study design	Selection					Outcome
		Representativeness of exposed cohort	Comparability	Ascertainment of exposure	Demonstration that outcome of interest was not present at start of study		Assessment of outcome	Enough follow-up length
Taha 2015	Cohort	Truly representative	Single institution	Medical center registry records	Yes		Independent Assessment	No (retrospective)