Dairy product consumption and gastric cancer risk: A meta-analysis

Table 4 Methodological quality of case-control studies included in this meta-analysis

Ref.	Adequate definition of cases	Representativeness of cases	Selectionof control	Definition of control	Control for important factor or additional factor1	Exposure assessment	Same method of ascertainment for cases and cohorts	Nonresponse rate2	Total quality scores
Correa et al[59], 1985	*	*	-	*	**	*	*	-	7
Wu-Williams et al[60], 1990	*	*	*	-	-	*	*	-	5
Mettlin et al[24], 1990	-	*	-	*	**	*	*	-	6
Boeing et al[61], 1991	*	*	-	*	*	*	*	-	6
Boeing et al[62], 1991	*	*	-	*	*	*	*	-	6
Yu et al[63], 1991	*	*	*	*	**	*	*	-	8
Hoshiyama et al[39], 1992	*	*	*	-	**	*	*	-	7
Memik et al[64], 1992	*	*	*	*	-	-	*	-	5
Hansson et al[65], 1993	*	*	*	-	*	*	*	-	6
Inoue et al[66], 1994	*	*	-	*	-	*	*	*	6
Falcao et al[67], 1994	*	*	-	*	-	*	*	-	5
Cornée et al[68], 1995	*	*	-	*	*	*	*	-	6
Muñoz et al[4], 1997	*	*	-	*	*	*	*	-	6
Watabe et al[69], 1998	*	*	*	-	-	*	*	-	5
Ward et al[70], 1999	*	*	*	*	**	*	*	-	8
Muñoz et al[71], 2001	*	*	*	-	**	*	*	-	7
Kim et al[72], 2002	*	*	-	*	*	*	*	-	6
Chen et al[73], 2002	*	*	*	-	**	*	*	-	7
Ito et al[74], 2002	*	*	-	*	**	*	*	-	7
Lissowska et al[75], 200	*	*	*	-	**	*	*	-	7
De Stefani et al[76], 2004	*	*	-	*	**	*	*	-	7
Huang et al[77], 2004	-	*	-	*	*	*	*	-	5
Fei et al[78], 2006	*	*	-	*	-	*	*	-	5
Lucenteforte et al[79], 2008	*	*	-	*	**	*	*	-	7
Chen et al[80], 2009	*	*	-	*	*	*	*	-	6
Pourfarzi et al[81], 2009	*	*	*	*	*	*	*	-	7
Lazarevic et al[82], 2010	*	*	-	*	**	*	*	-	7
Icli et al[83], 2011	*	*	-	*	-	*	*	-	5
Pakseresht et al[84], 2011	*	*	*	*	**	*	*	-	8

¹A maximum of two stars could be awarded for this item. Studies that controlled for age received one start, whereas studies that controlled for smoking or drinking received an additional start;

²One star was assigned if there was no significant difference in the response rate between case and control subjects by using the χ² test (P = NS). NS: Not significant.