Table 2.

Results of overall and subgroups analyses of pooled ORs and 95% CIs

Genetic model	Subgroup	Number of studies	OR (95% CI)	I 2 (%)
T vs. C	Overall	25	0.99 (0.79-1.23)	62.2
	Caucasian	16	0.89 (0.72-1.09)	52.92
	Asian	7	1.99 (0.84-4.69)	73.63
	Other ethnic	2	0.67 (0.34-1.31)	0
	HWE (yes)	20	1.02 (0.82-1.27)	51.3
	HWE (no)	5	0.83 (0.38-1.82)	83.19
	HB	9	1.53 (0.89-2.64)	65.78
	PB	13	0.82 (0.64-1.06)	57.02
	Mixed	3	1.02 (0.53-1.96)	57.81
TT vs. CC	Overall	23	1.14 (0.78-1.66)	35.7
	Caucasian	14	0.99 (0.65-1.51)	31.23
	Asian	7	1.58 (0.35-6.62)	56.26
	Other ethnic	2	0.81 (0.03-20.41)	0
	HWE (yes)	18	1.26 (0.82-1.94)	23.2
	HWE (no)	5	0.58 (0.16-2.11)	61.03
	HB	9	1.48 (0.77-2.86)	38.86
	PB	11	0.70 (0.32-1.56)	50.29
	Mixed	3	1.42 (0.53-3.76)	0
CT vs. CC	Overall	23	0.97 (0.70-1.36)	59.1
	Caucasian	14	0.87 (0.60-1.26)	57.75
	Asian	7	1.57 (0.63-3.91)	64.84
	Other ethnic	2	0.66 (0.32-1.36)	0
	HWE (yes)	18	0.89 (0.71-1.11)	39
	HWE (no)	5	0.98 (0.26-3.77)	84.49
	HB	9	1.43 (0.77-2.66)	58.68
	PB	11	0.79 (0.52-1.21)	51.96
	Mixed	3	0.81 (0.33-2.02)	65.39
(CT + TT) vs. CC	Overall	23	1.02 (0.76-1.37)	55.1
	Caucasian	14	0.90 (0.66-1.23)	50.66
	Asian	7	1.97 (0.85-4.53)	63.16
	Other ethnic	2	0.65 (0.31-1.33)	0
	HWE (yes)	18	0.94 (0.76-1.16)	35.9
	HWE (no)	5	0.89 (0.29-2.75)	82.18
	HB	9	1.56 (0.90-2.73)	54.51
	PB	11	0.83 (0.58-1.19)	47.83
	Mixed	3	0.90 (0.37-2.22)	66.87
TT vs. (CT + CC)	Overall	23	1.22 (0.85-1.75)	35.2
	Caucasian	14	1.11 (0.75-1.63)	16.14
	Asian	7	1.11 (0.13-9.92)	70.43
	Other ethnic	2	0.92 (0.04-23.08)	0
	HWE (yes)	18	1.42 (0.93-2.17)	37.6
	HWE (no)	5	0.80 (0.40-1.61)	20.27
	HB	9	1.03 (0.27-3.88)	59.09
	PB	11	1.04 (0.66-1.65)	36.77
	Mixed	3	1.74 (0.67-4.52)	0

HWE: Hardy Weinberg Equilibrium; Mixed: hospital and population based; PB: population based; HB: hospital based.