Table 3 Ratings of methodological quality of included studies
Study | Risk of selection bias | Confounders | Data collection methods | Withdrawals and dropouts | Analysis | Quality rating |
|---|---|---|---|---|---|---|
Aihara and Minai [32] | Mod | Strong | Weak | Mod | Mod | Mod |
Kan and Tsai [39] | Mod | Strong | Weak | Mod | Mod | Mod |
Kelly-Irving et al. [36] | Weak | Weak | Mod | Mod | Weak | Weak |
Lutfiyya et al. [33] | Mod | Strong | Mod | Mod | Mod | Mod |
Lutfiyya et al. [34] | Mod | Strong | Mod | Mod | Mod | Mod |
Murata et al. [35] | Mod | Weak | Strong | Weak | Mod | Mod |
Periera et al. [37] | Mod | Weak | Weak | Strong | Mod | Mod |
Sohn et al. [40] | Weak | Weak | Strong | Weak | Mod | Weak |
Wyatt et al. [38] | Strong | Strong | Mod | Mod | Mod | Mod |