Table 3. Newcastle-Ottawa Quality Assessment of Cross-sectional, Cohort and Case-control Studies.

max. = maximum

Newcastle-Ottawa Quality Assessment
Newcastle-Ottawa Quality Assessment of Cross-sectional Studies
Studies	Selection (max. 5 stars)	Comparability (max. 2 stars)	Outcome (max. 3 stars)	Total Score (max. 10)
Minotti et al. [12]	3	2	3	8
Kuwabara et al. [13]	4	2	3	9
Yildiran et al. [14]	3	2	3	8
Newcastle-Ottawa Quality Assessment of Cohort Studies
Studies	Selection (max. 4 stars)	Comparability (max. 2 stars)	Outcome (max. 3 stars)	Total Score (max. 9)
Prentice et al. [15]	3	2	2	7
Huang et al. [16]	3	2	3	8
Lee et al. [17]	4	2	3	9
Eshak et al. [18]	4	2	3	9
Zhao et al. [19]	4	2	3	9
Stepaniak et al. [20]	4	2	2	8
Cangemi et al. [21]	3	2	2	7
Wannamethe et al. [22]	4	2	3	9
Espe et al. [23]	3	2	3	8
Goyal et al. [24]	3	2	3	8
Ferro et al. [25]	3	2	2	7
Newcastle-Ottawa Quality Assessment of Case-control Studies
Llopis-González et al. [26]	4	2	2	8
Godala et al. [27]	2	2	3	7
Xu et al. [28]	2	2	3	7
Naidoo et al. [29]	4	2	2	8
Nagao [30]	4	2	2	8