“…Most of the included studies ( n = 39, 63 %) were published between 2005–2013 (Fig. 2 ) [ 13 , 14 , 28 , 30 – 34 , 36 , 38 , 39 , 42 – 48 , 50 – 52 , 55 – 59 , 63 , 67 , 69 – 71 , 73 – 77 , 79 – 81 ]. The majority of studies were retrospective cohort studies ( n = 29, 47 %) [ 2 , 25 , 27 , 28 , 30 – 36 , 38 , 40 , 41 , 43 , 44 , 49 – 51 , 55 , 61 , 62 , 65 , 66 , 70 , 72 , 80 , 82 , 83 ], while 29 % were prospective cohort studies ( n = 18) [ 26 , 29 , 37 , 39 , 42 , 46 – 48 , 52 – 54 , 56 , 60 , 67 , 71 , 74 , 79 , 81 ] and 11 % ( n = 7) were randomized controlled trials or cohort [ 57 – 59 , 69 , 75 ...…”