. 2018 Apr 26;9:452. doi: 10.3389/fphys.2018.00452

Table 2.

The Newcastle-Ottawa Scale (NOS) quality assessment of the enrolled studies.

Study ID		Selection		Comparability			Outcome		Total

	Representativeness of the exposed cohort	Selection of the non-exposed cohort	Ascertainment of exposure	Demonstration that outcome of interest was not present at start of study	Comparability of cohorts on the basis of the design or analysis (study adjusts for age^∗, ex^∗)	Assessment of outcome	Was follow-up long enough for outcomes to occur	Adequacy of follow up of cohorts
Irie et al., 2005	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Zhang et al., 2012	-	^∗	^∗	-	^∗∗	^∗	^∗	^∗	7
Gu et al., 2013	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Jiang et al., 2013	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Kong et al., 2014	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Schulkens et al., 2014	-	^∗	^∗	-	-	^∗	^∗	^∗	5
Fu et al., 2015	-	^∗	^∗	-	^∗∗	^∗	^∗	^∗	7
Grosset et al., 2016	-	^∗	^∗	-	-	^∗	^∗	^∗	5
Ohue et al., 2016	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Wang et al., 2016	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Choi et al., 2017	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Liu et al., 2017	-	^∗	^∗	-	^∗∗	^∗	^∗	^∗	7
Melief et al., 2017	-	^∗	^∗	^∗	^∗∗	^∗	^∗	^∗	8
Sideras et al., 2017	-	^∗	^∗	-	^∗∗	^∗	^∗	^∗	7

^∗Means one score, ^∗∗means two scores.