Table 2.

Quality assessment of included studies*

First author	Year	Random sample or whole population	Unbiased sampling frame (i.e. census data)	Adequate sample size (>300 subjects)	Measures were the standard	Outcomes measured by unbiased assessors	Adequate response rate (70%) and refusers described	Confidence intervals and subgroup analysis	Study subjects descirbed	Quality risk rating/8
Bethell	2011	1	1	1	1	1	1	1	1	8
NSCH	2011/2012	1	1	1	1	1	1	1	1	8
CHIS	2003	1	1	1	1	1	1	0	1	7
CHIS	2005	1	1	1	1	1	1	0	1	7
CHIS	2009	1	1	1	1	1	1	0	1	7
CHIS	2007	1	1	1	1	1	1	0	1	7
Ibironke	2011	1	1	1	1	1	0	1	1	7
Zuckerman	2009	1	1	1	1	1	0	1	1	7
Glascoe	2013	1	1	1	1	1	0	0	1	6
Stevens	2006	1	1	1	0	1	0	1	1	6
Ng	2010	1	1	1	1	1	0	0	1	6
Restall	2009	1	1	0	1	1	0	1	1	6
VSEHQ	2008	1	1	1	1	1	0	0	1	6
Davies	2009	1	1	0	1	1	1	0	0	5
Glascoe	1999	0	1	1	1	1	0	0	1	5
Glascoe	1997	0	1	1	1	1	0	0	1	5
Rose Jacobs	2008	0	0	1	1	1	1	0	1	5
Glascoe	2010	0	0	1	1	1	0	0	1	4
Glascoe	2010	0	0	1	1	1	0	0	1	4
Kosht-Fedyshin	2006	1	0	0	1	1	0	0	1	4
Limbos	2011	0	0	1	1	1	1	0	1	5
Oreto	2010	0	0	1	1	1	0	0	1	4
Tough	2008	0	0	1	1	1	0	0	1	4
Armstrong	2008	0	1	0	1		0	0	1	3
Campos	2010	0	0	1	1	1	0	0	0	3
Coghlan	2003	0	0	0	1	1	0	0	1	3
Kiing	2012	0	0	1	1	1	0	0	0	3
McGookin	2011	0	0	1	1	1	0	0	0	3
Palarca	2008	0	0	1	1	1	0	0	1	3
Roux	2011	0	0	1	1	1	0	0	0	3
Theeranate	2005	0	0	0	1	1	0	0	1	3
Wake	2005	0	0	1	1	1	0	0	0	3
Gustawan	2010	0	0	0	1	1	0	0	1	3
Chuan	2012	0	0	0	1	1	0	0	0	2
Mahli	2002	0	0	0	1	1	0	0	0	2
Matibag	2008	0	0	0	1	1	0	0	0	2
Sices	2009	0	0	0	1	1	0	0	0	2

*Quality rating system as per quality rating tool developed by Public Health Agency in Canada [19].