Table 1: Characteristics of the included studies.

First authorYearCountryCaseControl
Age (years)ET-1 (pg/mL)Age (years)ET-1 (pg/mL)

NTG studies
Henry2006England88
Lee2012Korea4535
Sugiyama1995Japan5210
Chen2013China1837
Kunimatsu2006Japan3019
Galassi2011Italy4440
Cellini1997Italy1564.71565.8

POAG studies
Sugiyama1995Japan1010
Chen2013China3137
Nicolela2003Canada4124
Cellini2012Italy4040
Kunimatsu2006Japan1819
Holló1998Hungary2044

: number; data are expressed as mean ± standard deviation (SD).