Table S1.

Newcastle–Ottawa scale (NOS)

Reference	Is the case definition adequate?	Representativeness of the cases	Selection of controls	Definition of controls	Comparability of cases and controls on the basis of the design or analysis	Ascertainment of exposure	Same method of ascertainment for cases and controls	Nonresponse rate	Total scores
Barbier et al 20111	⋆	⋆	⋆	⋆	⋆	⋆	⋆	☆	7
Casadei et al 20152	⋆	⋆	⋆	⋆	⋆⋆	⋆	☆	☆	7
Papalezova et al 20123	⋆	☆	⋆	⋆	⋆⋆	☆	⋆	☆	6
Golcher et al 20154	⋆	⋆	☆	⋆	⋆⋆	⋆	⋆	⋆	8
Mokdad et al 20175	⋆	☆	⋆	⋆	⋆⋆	⋆	⋆	⋆	8
Moutardier et al 20046	⋆	⋆	⋆	⋆	⋆⋆	☆	⋆	☆	7
Vento et al 20077	⋆	⋆	☆	⋆	⋆⋆	⋆	⋆	☆	7
Tajima et al 20128	⋆	⋆	☆	⋆	⋆⋆	☆	⋆	☆	6
Motoi et al 20149	⋆	⋆		⋆	⋆⋆	⋆	⋆	☆	7
Fujii et al 201710	⋆	⋆	⋆	⋆	⋆⋆	☆	⋆	☆	7
Tzeng et al 201411	⋆	⋆	⋆	⋆	⋆⋆	☆	⋆	☆	7

Notes: ⋆, Get one point; ☆, get no point.