“…In the contrary studies that were rated as yes (reported) in the quality assessment questions considered as low risk of bias. As a result, more than 80% of the studies had clearly settled objectives, 17 , 29–69 specified study populations, 17 , 29–35 , 37 , 39–53 , 55 , 56 , 58 , 60–64 , 66–69 inclusion/exclusion criteria, 17 , 29–35 , 37 , 40 , 42–51 , 53–57 , 59 , 61–69 adjusted confounders, 17 , 29–69 defined dependent variables, 17 , 29 , 30 , 32–44 , 46–51 , 53 , 55–58 , 63–69 and independent variables. 17 , 29–31 , 33 , 34 , 36 , 37 , 39–44 , 46–49 , 51–60 , 63–65 , 69 Whereas ≥50% participation rate, 29–31 , 33–35 , 37 , 39–42 , 44 , 46 , 48 , 50–53 , 55 , 56 , 61–63 , 65 , 68 , 69 justified sample size determination, 29–32 , 34 , 37–40 , 42–44 , 46–52 , 55–57 ,…”