Table 4:

Newcastle-Ottawa Scale (NOS) for Cohort

	Selection				Comparability	Outcome assessment
	Representativeness of the Exposed Cohort (Max.1)	Selection of the Non-Exposed Cohort (Max.1)	Ascertainment of Exposure (Max.1)	Demonstration that Outcome of Interest was Not Present at Start of Study (Max.1)	Comparability of Cohorts Based on Design or Analysis (Max.2)	Assessment of Outcome (Max.1)	Was Follow-Up Long Enough for Outcomes to Occur (Max.1)	Adequacy of Follow-Up of Cohorts (Max.1)	Score (Max.9)	Quality Score
Orlich et al., (39)	1	1	0	0	0	1	1	1	5	Poor
Tu et al., (40)	1	1	0	0	0	1	1	1	5	Poor
*Navratilova et al., (47)	1	1	1	1	2	1	1	1	9	Good
Garcia et al., (49)	1	1	1	0	0	0	1	1	5	Poor

Key: Scoring Interpretation

Good Quality: 3 or 4 stars in the Selection domain AND 1 or 2 stars in the Comparability domain AND 2 or 3 stars in the Outcome domain

Fair Quality: 2 stars in the Selection domain AND 1 or 2 stars in the Comparability domain AND 1 or 2 stars in the Outcome domain

Poor Quality: 0 or 1 star in Selection domain OR 0 stars in Comparability domain OR 0 or 1 star in Outcome domain

^*The star symbol represents studies that directly address the research question