Table 3.

The Newcastle–Ottawa scale of included studies: reviewers judgment

Sample representativeness (selection)Sample size (selection)Counfounding controlled (comparability)Statistical tests (outcome)Total stars and quality rating
Park et al., 2011 (22)***3/6 moderate
Cole et al., 2002 (23)****4/6 moderate
Cole et al., 2003 (24)****4/6 moderate
Crotta et al., 2004 (25)**2/6 low
Fenochi et al., 2006 (26)*1/6 low
Chen et al., 2007 (27)*1/6 low
van Rossum et al., 2008 (28)****4/6 moderate
Parente et al., 2009 (29)**2/6 low
Levy et al., 2010 (30)*1/6 low
Cai et al., 2011 (31)****4/6 moderate
Gregory et al., 2011 (32)**2/6 low
Senore et al., 2012 (33)***3/6 moderate
Hol et al., 2012 (34)****4/6 moderate
Quintero et al., 2012 (35)****4/6 moderate
Ferrari et al., 2012 (36)****4/6 moderate
McDonald et al., 2012 (37)***3/6 moderate
Kluhsman et al., 2012 (38)*1/6 low
Gupta et al., 2013 (39)***3/6 moderate
Kelley et al., 2013 (40)****4/6 moderate