. 2021 Jan 22;100(3):e24170. doi: 10.1097/MD.0000000000024170

Table 3.

Quality of evidence.

		Selection				Comparability	Outcome
Author/yr	Region/country	1) Representativeness of the sample	2) Sample size	3) Non-respondents	4) Ascertainment of the exposure (risk factor)	1) Confounding factors are controlled	1) Assessment of the outcome	2) Statistical test	Total	Quality
Clarke 2005	Washington/US	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Ahn 2011	Republic of Korea	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Sasson 2011	Atlanta/US	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Sasson 2012	29 sites/US	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Chiang 2014	Taipei/Taiwan	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Lee 2016	Republic of Korea	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Moncur 2016	North East England/UK	^∗∗	–	NA	^∗	-	^∗∗	^∗	6	middle
Dahan 2017	Paris/France	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Chang 2018	Republic of Korea	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high
Lee 2018	Republic of Korea	^∗∗	–	NA	^∗	^∗∗	^∗∗	^∗	8	high

^∗NA = non applicable, UK = United Kingdom, US = United States.

^∗The sample size item was not rated in all literature. When calculating the total score, it was treated as 0.