Quality assessment
Two independent reviewers conducted the methodological quality assessment of each study according to the quality of genetic studies (Q-Genie) tool which was developed by Sohani et al.22 in 2015 and subsequently validated. This tool consists of 11 items scored on a 7-point Likert scale specifically applicable to the quality assessment of published genetic association studies [22, 23]. In studies without control groups, scores ≤32 indicate poor quality studies, 33-40 indicate moderate quality studies, and >40 indicate good quality studies. For studies with control groups, scores for the parameters listed above are ≤35, 36-45, and >45, respectively[22].