Table 2.

Summary of the result

Study	Cases	Controls	OR	95% CI	Z	P	Weight (%)
							Fixed	Random
Zhengetal., 1990[17]	50/404	29/404	1.826	1.1302.952			15.46	15.46
Bundgaardetal., 1995[18]	88/161	167/483	2.281	1.5873.278			27.11	27.11
Garroteetal., 2001[19]	148/200	103/200	2.68	1.7604.081			20.16	20.16
Lissowskaetal., 2003[21]	89/122	65/124	2.448	1.4374.170			12.56	12.56
Rosenquistetal., 2005[22]	28/132	22/320	3.647	1.9996.654			9.85	9.85
Changetal., 2013[25]	68/317	25/296	2.96	1.8144.831			14.86	14.86
Total (fixedeffects)	471/1336	411/1827	2.496	2.0673.015	9.5	<0.001	100	100
Total (randomeffects)	471/1336	411/1827	2.501	2.0713.020	9.518	<0.001	100	100

OR: Odds ratio; CI: Confidence interval