Table 1.

Characteristics of case-control studies included in the meta-analysis.

First author	Year	Country	Ethnicity	Distribution of PAI genotypes						Sample Size (DR/DWR)	HWE	Reference Number
				4G/4G		4G/5G		5G/5G
				DR	DWR	DR	DWR	DR	DWR
Nagi	1997	U.S.A.	Pima Indian	14	18	44	45	12	39	70/102	0.43	[19]
Broch	1998	Spain	Caucasian	17	19	46	48	19	28	82/95	0.85	[21]
Wong	2000	China	East Asian	31	16	38	28	15	13	84/57	0.91	[23]
Santos	2003	Brazil	Caucasian	24	22	41	59	34	30	99/111	0.47	[16]
Globocnik-Petrovic	2003	Slovenia	Caucasian	39	25	58	40	27	15	124/80	0.89	[18]
Liu	2004	China	East Asian	15	27	26	49	15	15	56/91	0.36	[24]
Zietz	2004	Germany	Caucasian	48	112	55	173	28	73	131/358	0.68	[20]
Murata	2004	Japan	East Asian	78	43	86	35	24	14	188/92	0.14	[22]
Ezzidi	2009	Tunisia	Caucasian	77	54	167	242	139	177	383/473	0.56	[17]

DR: diabetic retinopathy; DWR: diabetes without retinopathy; HWE: Hardy-Weinberg equilibrium.