“…According to the SIGN checklist, 18 of the studies [ 7 , 20 , 28 , 30 , 31 , 33 , 35 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 49 , 55 ] were rated “high quality” and 17 studies were “acceptable quality” [ 5 , 6 , 15 , 19 , 29 , 34 , 36 , 46 , 47 , 48 , 50 , 51 , 52 , 53 , 54 , 56 ]. Although the studies were rated as being high and acceptable quality, for sample selection random assignment was used and no detailed description of the procedure was provided.…”