“…Of the 35 studies selected for the methodological assessment using the Downs and Black scale [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 ], 1 study scored 6/17 [ 35 ], 3 scored 7/10 [ 36 , 37 , 38 ], 11 scored 8/17 [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ], 12 scored 9/17 [ 50 , 51 ,…”