Table 1.

Characteristics of the 7 studies included in the meta-analysis.

Author	Year	Country	Ethnicity	Age, years mean ± SD or mean (range)		Samples, n		Genotying method
				Cases	Controls	Cases	Controls
Austin et al	2007	United States	African Americans	46.5 ± 12.9	45.4 ± 10.6	377	187	PCR-sequencing
Möller et al	2006	South Africa	South Africans	34 ± 14.8	27 ± 12.3	432	482	Taq Man SNP genotyping assays
Singh et al	2012	Northern Indian states	Indians	33.18 ± 13.29	36.85 ± 12.6	263	122	PCR-RFLP
Stockton et al	2004	Gambia	Gambians	36 (19-58)	32 (18-50)	320	320	PCR-RFLP, PCR-FRET
Zhao et al_a	2012	China	Chinese Han	36.47 ± 15.73	37.02 ± 15.29	219	215	PCR-sequencing
Zhao et al_b	2012	China	Chinese Uygur	28.8 ± 10.1	30.1 ± 8.9	86	72	PCR-sequencing
Zhao et al_c	2012	China	Chinese Kazak	28.8 ± 10.1	37.02 ± 15.29	120	93	PCR-sequencing

PCR = polymerase chain reaction; RFLP = restriction fragment length polymorphism; FRET = fluorescence resonance energy transfer.