Vitamin D receptor gene polymorphisms and colorectal cancer risk: A systematic meta-analysis

Table 1 Characteristics of case-control studies included in the meta-analysis

First author	Year	Country	Racial descent	Mean age in cases	Mean age in controls	Cases/controls	Genotyping method	Quality control	Adjusted	Studied polymorphisms
Ingles et al[11]	1998	United States	American	62.3	62.2	373/394	PCR-RFLP	Yes	Yes	FokI
Kim et al[13]	2001	United States	American	58.0 ± 9.7	53.0 ± 11.0	393/406	TaqMan	Yes	Yes	BsmI
Peters et al[27]	2001	United States	American	18-74	18-74	208/184	PCR-RFLP	Yes	NR	FokI
Slatter et al[23]	2001	United States	American	NR	NR	424/366	PCR-RFLP	NR	Yes	FokI, BsmI, TaqI
Speer et al[14]	2001	Hungary	European	64	63	56/112	PCR-RFLP	NR	NR	BsmI
Grau et al[29]	2003	United States	American	60.8 ± 9.0	60.9 ± 9.0	372/379	PCR-RFLP	Yes	Yes	FokI, TaqI
Wong et al[28]	2003	Singapore	Asian	66	56.5	217/890	PCR-RFLP	Yes	Yes	FokI
Peters et al[35]	2004	United States	American	62.9	62.3	763/774	PCR-RFLP	Yes	NR	TaqI
Slattery et al[15]	2004	United States	American	30-79	30-79	1936/2130	PCR-RFLP	NR	Yes	FokI, BsmI
Murtaugh et al[30]	2006	United States	American	30-79	30-79	2450/2821	PCR-RFLP	NR	Yes	FokI
Park et al[16]	2006	South Korea	Asian	55	55	190/354	PCR-RFLP	NR	Yes	FokI, BsmI, ApaI, TaqI
Flügge et al[12]	2007	Germany	European	61.9 ± 10.0	62.2 ± 11.2	256/256	PCR-RFLP	Yes	Yes	Cdx-2, FokI, BsmI, ApaI, TaqI
Kadiyska et al[19]	2007	Bulgaria	European	59	59 ± 5	133/94	PCR-RFLP	NR	Yes	BsmI
Slattery et al[18]	2007	United States	American	30-79	30-79	2380/2990	TaqMan	Yes	Yes	FokI, BsmI
Yaylim-Eraltan et al[31]	2007	Turkey	European	59.1 ± 4.0	52.0 ± 0.8	26/52	PCR-RFLP	NR	Yes	FokI, TaqI
Grünhage et al[32]	2008	Germany	European	65 ± 9	63 ± 8	192/220	PCR-RFLP	NR	Yes	FokI
Hubner et al[17]	2008	United Kingdom	European	NR	NR	137/409	TaqMan	Yes	Yes	Cdx-2, FokI, BsmI, ApaI, TaqI
Ochs-Balcom et al[24]	2008	United States	American	62.8 ± 10.2	58.5 ± 12.1	250/246	TaqMan	Yes	Yes	Cdx-2, FokI, TaqI
Parisi et al[20]	2008	Spain	European	NR	NR	170/120	PCR-RFLP	NR	Yes	BsmI
Theodoratou et al[21]	2008	United Kingdom	European	62.0 ± 10.8	62.4 ± 10.5	3005/3072	Microarray	Yes	Yes	Cdx-2, FokI, BsmI, ApaI
Wang et al[33]	2008	China	Asian	38-78	19.6 ± 1.3	69/218	PCR-RFLP	NR	Yes	FokI
Jenab et al[22]	2009	Europe	European	NR	NR	1248/1248	TaqMan	Yes	Yes	FokI, BsmI
Mahmoudi et al[34]	2010	Iran	Asian	52.7 ± 14.0	44.4 ± 17.7	160/180	PCR-RFLP	Yes	Yes	ApaI, TaqI

NR: Not reported.