Table 3.

Meta-analysis for 1G/2G polymorphism with OA risk.

Category	na	2G2G vs. 1G1G				2G2G + 2G1G vs. 1G1G				2G2G vs. 2G1G + 1G1G				2G vs. 1G
		I2 (%)	Pb,c	OR (95% CI)	Pd	I2 (%)	Pb,c	OR (95% CI)	Pd	I2 (%)	Pb,c	OR (95% CI)	Pd	I2 (%)	Pb,c	OR (95% CI)		Pd
Total	5	87.8	0.00	0.69 (0.36–1.32)	0.54	80.9	0.00	0.88 (0.47–1.63)	0.69	87.1	0.00	1.30 (0.68–2.47)	0.41	89.0	0.00	0.90 (0.86–1.54)		0.66
OA type
Knee	4	88.3	0.00	1.06 (0.35–3.25)	0.90	84.7	0.00	1.00 (0.43–2.34)	0.98	84.7	0.00	1.09 (0.55–2.14)	0.79	91.1	0.00	0.96 (0.52–1.76)		0.90
Other	1	/	/	2.92 (1.64–5.19)	0.00	/	/	0.60 (0.38–0.9)	0.02	/	/	2.53 (1.54–4.15)	0.00	/	/	0.69 (0.50–0.96)		0.03
Ethnicity
Asian	2	90.6	0.00	1.22 (0.25–5.99)	0.61	79.0	0.02	0.89 (0.39–2.03)	0.79	90.7	0.00	1.48 (0.53–4.14)	0.45	80.2	0.02	0.90 (0.55–1.47)		0.68
Caucasian	3	91.0	0.00	1.22 (0.25–5.99)	0.80	87.4	0.00	0.91 (0.30–2.79)	0.87	89.6	0.00	1.20 (0.42–3.48)	0.72	93.6	0.00	0.90 (0.37–2.20)		0.83
Age
<60	2	2.5	0.31	3.46 (2.13–5.62)	0.00	41.3	0.19	0.49 (0.31–0.79)	0.00	0.0	0.56	2.74 (1.80–4.16)	0.00	69.7	0.06	0.56 (0.35–0.89)		0.01
≥60	3	83.2	0.00	0.66 (0.23–1.88)	0.43	78.7	0.00	1.42 (0.59–3.39)	0.43	78.6	0.00	0.82 (0.45–1.46)	0.49	87.3	0.00	1.25 (0.71–2.19)		0.44

I², 0–25: no heterogeneity; 25–50: modest heterogeneity; 50: high heterogeneity.

^aNumber of studies.

^bP value for heterogeneity test.

^cRandom effect model was used when P value < 0.05 for heterogeneity test; otherwise, fixed effect model was used.

^dP value for each test.