Table 2. Characteristics of the Studies about the XRCC1 Arg399Gln polymorphism (rs25478) Included in the Meta-analysis.

Author	Year	Ethnicity	Cancer Site	Genotyping Method	Control Source	Matching Criteria	Adjusted Variables	Case				Control				HWEd	MAFe
								N	AA	AB	BB	N	AA	AB	BB
Dos Reis	2013	Mixed	Oral	PCR-RFLP	PBa	Age, sex, race, smoke	None	150	64	62	24	150	62	54	34	0.002	0.407
Yuan	2012	Asian	Head&neck	TaqMan	PB	Age, sex	Age, sex, smoke, alcohol	390	221	146	23	886	481	339	66	0.558	0.266
Sturgis	1999	Mixed	Head&neck	PCR-RFLP	HBb	Age, sex, race	None	203	94	77	32	424	181	197	46	0.483	0.341
Majumder	2005	Asian	Oral	PCR-RFLP	HB	None	None	310	135	143	32	348	158	163	27	0.088	0.312
Harth	2008	Caucasian	Head&neck	RT-PCR	HB	None	Age, sex	310	114	166	30	300	143	121	36	0.189	0.322
Applebaum	2009	Mixed	Head&neck	PCR-RFLP	PB	Age, sex	Age, sex, race, education, smoke, alcohol, HPV16	483	192	229	62	547	232	246	69	0.763	0.351
Li	2007	Caucasian	Head&neck	PCR-RFLP	PB	Age, sex, race	Age, sex, smoke, alcohol	830	335	374	121	854	360	385	109	0.702	0.353
Majumder	2007	Asian	Oral	PCR-RFLP	HB	None	Age, sex, smoke	309	134	143	32	385	170	179	36	0.255	0.326
Tae	2004	Asian	Head&neck	MAPA	HB	None	Age, smoke, alcohol	129	69	51	9	157	86	64	7	0.251	0.248
Varzim	2003	Caucasian	Larynx	PCR-RFLP	PB	None	None	88	37	40	11	178	80	80	18	0.759	0.326
Csejtei	2009	Caucasian	Head&neck	PCR-RFLP	HB	Age, sex	None	108	50	47	11	102	53	41	8	0.986	0.279
Kowalski	2009	Caucasian	Head&neck	PCR-RFLP	HB	Age	None	92	37	44	11	124	49	53	22	0.253	0.391
Demokan	2005	Caucasian	Head&neck	PCR-RFLP	PB	None	None	95	42	41	12	98	39	46	13	0.922	0.367
Krupa	2011	Caucasian	Larynx	PCR-RFLP	HB	Age, sex	None	253	93	111	49	253	105	113	35	0.603	0.362
Kostrzewska-Poczekaj	2013	Caucasian	Head&neck	PCR-RFLP	PB	None	None	290	110	154	26	158	50	81	27	0.550	0.427
Jelonek	2010	Caucasian	Head&neck	PCR-RFLP	PB	Age, sex	None	104	47	50	7	110	35	62	13	0.068	0.400
Ramachandran	2006	Asian	Oral	PCR-RFLP	PB	Age, sex	Age, sex, smoke, alcohol, betel quid chewing	110	46	48	16	110	73	33	4	0.910	0.186
Olshan	2002	Caucasian	Head&neck	PCR-RFLP	HB	Age, sex	Age, sex	98	45	50	3	161	62	82	17	0.183	0.360
Kietthubthew	2006	Asian	Oral	PCR-RFLP	PB	Age, sex, smoke, alcohol, betel chewing, religion	None	106	55	45	6	164	67	74	23	0.724	0.366
Kumar	2012	Asian	Head&neck	PCR-RFLP	PB	Age, sex, habits	None	278	128	124	26	278	98	144	36	0.133	0.388
Gugatschka	2011	Caucasian	Head&neck	TaqMan	PB	None	None	168	70	74	24	463	204	198	61	0.241	0.346
Ho	2007	Mixed	Oral	PCR-RFLP	HB	None	Age, sex, ethnicity, family history, smoke, alcohol, radiation exposure	138	61	62	15	503	220	216	67	0.229	0.348
Rydzanicz	2005	Caucasian	Head&neck	PCR-RFLP	PB	Smoke, occupational exposure	None	182	63	98	21	143	59	63	21	0.535	0.367
Gajecka	2005	Caucasian	Larynx	PCR-RFLP	PB	None	None	293	106	153	34	319	124	145	50	0.484	0.384
Matullo	2006	Caucasian	Head&neck	TaqMan	UKc	None	None	82	34	38	10	1094	484	482	128	0.632	0.337

^aPB: Population based;

^bHB: Hospital based;

^cUK: Unknown or unstated;

^dHWE: Hardy-Weinberg equilibrium in controls;

^eMAF: Minor allele frequency in controls.