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.

Table 2 Summary odds ratios and 95% CI in the vitamin D receptor gene

SNP	Model	Total No. cases	Total No. controls	OR (95% CI)1	P value2	P value3
Cdx-2	Codominant (CC vs cc)	152/1561	146/1820	1.25 (0.98-1.59)	0.07	0.26
	Codominant (Cc vs cc)	926/2487	982/2802	1.09 (0.97-1.22)	0.15	0.64
	Codominant (C vs C)	1230/4048	1279/4622	1.10 (1.01-1.21)	0.03	0.47
	Dominant (CC + Cc vs cc)	1078/1561	1208/1820	0.98 (0.88-1.09)	0.72	< 0.001
	Recessive (CC vs Cc + cc)	152/2487	146/2802	1.22 (0.96-1.54)	0.10	0.23
FokI	Codominant (ff vs FF)	1844/5068	2377/5982	0.94 (0.87-1.01)	0.09	0.001
	Codominant (Ff vs FF)	6189/11 257	7583/13 565	0.98 (0.93-1.03)	0.34	0.001
	Codominant (f vs F)	9867/16 320	12 190/19 329	0.97 (0.94-1.00)	0.07	< 0.001
	Dominant (ff + Ff vs FF)	8033/5068	9960/5982	0.96 (0.92-1.01)	0.15	< 0.001
	Recessive (ff vs FF + Ff)	1844/11 257	2377/13 565	0.95 (0.89-1.02)	0.13	0.01
BsmI	Codominant (BB vs bb)	1512/3838	1817/4122	0.87 (0.80-0.94)	< 0.001	0.65
	Codominant (Bb vs bb)	4733/8571	5303/9425	0.94 (0.88-0.99)	0.03	0.64
	Codominant (B vs b)	7757/12 409	8937/13 577	0.93 (0.90-0.97)	< 0.001	0.85
	Dominant (BB + Bb vs bb)	6245/3838	7120/4122	0.92 (0.87-0.97)	0.003	0.84
	Recessive (BB vs Bb + bb)	1512/8571	1817/9425	0.90 (0.84-0.97)	0.006	0.28
ApaI	Codominant (AA vs aa)	748/578	1004/603	0.85 (0.73-0.99)	0.03	0.06
	Codominant (Aa vs aa)	1378/1956	1593/2196	0.91 (0.79-1.04)	0.18	0.39
	Codominant (A vs a)	2944/2534	3601/2799	0.92 (0.85-0.99)	0.02	0.04
	Dominant (AA + Aa vs Aa)	2161/578	2597/603	0.89 (0.78-1.01)	0.07	0.12
	Recessive (AA vs Aa + aa)	783/1956	1004/2196	0.89 (0.80-1.00)	0.05	0.21
TaqI	Codominant (tt vs TT)	382/1112	398/1320	1.05 (0.89-1.24)	0.58	0.07
	Codominant (Tt vs TT)	1086/2198	1298/2618	0.93 (0.83-1.05)	0.23	0.30
	Codominant (t vs T)	1850/3310	2098/3938	0.99 (0.92-1.08)	0.86	0.10
	Dominant (tt + Tt vs TT)	1468/1112	1696/1320	0.95 (0.85-1.07)	0.42	0.37
	Recessive (tt vs Tt + TT)	382/2198	398/2618	1.07 (0.92-1.25)	0.38	0.01

¹Based on fixed effects model;

²Test for overall effect;

³Test for heterogeneity. OR: Odds ratios.

Table 3 The BsmI effect odds ratios stratified by anatomical site

Model	Colon cancer			Rectal cancer
	Total No. cases/controls	OR (95% CI)	P value1	Total No. cases/controls	OR (95% CI)	P value1
Codominant (BB vs bb)	1365/1581	0.80 (0.68-0.93)	0.004/0.21	659/790	0.92 (0.73-1.15)	0.46/0.90
Codominant (Bb vs bb)	2257/2438	0.99 (0.88-1.12)	0.92/0.95	1029/1240	0.94 (0.80-1.11)	0.48/0.21
Codominant (B vs b)	5328/5972	0.91 (0.84-0.98)	0.01/0.25	2440/2966	0.95 (0.85-1.06)	0.38/0.99
Dominant (BB + Bb vs bb)	2664/2986	0.94 (0.84-1.05)	0.25/0.65	1220/1483	0.94 (0.77-1.16)	0.59/0.40
Recessive (BB vs Bb + bb)	2664/2986	0.80 (0.69-0.92)	0.002/0.19	1220/1483	0.93 (0.80-1.09)	0.40/0.51

¹Test for overall effect and heterogeneity, respectively. OR: Odds ratios.