Figure 1. Flowchart of study selection for the present study.

Table 1. The characteristics of included studies.

Table 1. The characteristics of included studies.

First Author, YearCountryEthnicitySample SizeGenotype Distribution (MM/Mm/mm)p Value for HWENOS ScoreCases ControlAbdulah, 2008United StatesCaucasian310/560139/121/50147/277/1360.888Zhou, 2008ChinaAsia1360/1360702/520/138592/605/1630.758Chen, 2009ChinaAsia212/232107/69/3671/114/470.968Kumar, 2011IndiaAsia301/424137/124/40174/190/600.637Cakmak, 2015TurkeyCaucasian220/24083/101/36102/118/200.217El-Menyar, 2015EgyptAsia236/152146/77/1284/58/1017Yang, 2018ChinaAsia540/548247/236/57244/251/530.498García-González, 2021YucatanCaucasian98/10123/53/2226/51/240.94 8

Table 2. Results of overall and subgroup analyses.

Table 2. Results of overall and subgroup analyses.

Genetic ModelPopulationNumber of StudiesTest of AssociationTest of HeterogeneityOR (95%CI)pPhI2, %ModelC vs. GTotal80.91 [0.79, 1.05]0.200.00270RAsian50.82 [0.71, 0.95]0.0070.0557RCaucasian31.12 [0.96, 1.30]0.160.339FCG vs. CC Total80.86 [0.78, 0.96]0.0070.000972RAsian50.85 [0.75, 0.95]0.0050.00165RCaucasian30.91 [0.70, 1.19]0.480.0285RGG vs. CCTotal80.80 [0.57, 1.12]0.190.000275RAsian50.76 [0.61, 0.91]0.0020.2624FCaucasian30.94 [0.30, 2.97]0.92<0.000191RGG + CGvs.CC Total80.78 [0.71, 0.86]0.13<0.0000137FAsian50.79 [0.70, 0.88]0.12<0.000146FCaucasian30.78 [0.63, 0.96]0.150.0247FGGvs.CC + CG Total80.92 [0.73, 1.16]0.470.0354RAsian50.88 [0.75, 1.05]0.150.770FCaucasian31.04 [0.47, 2.29]0.920.00185R