“…Forty-three of the studies were cohort studies (38 of which were prospective studies) and one was a secondary analysis of data from a randomised controlled trial (RCT) [ 57 ]. All studies were published between 2008 and 2018 with a wide geographical spread; four studies conducted in the UK [ 41 , 44 , 72 , 74 ], eight in the USA [ 40 , 45 , 47 , 50 , 56 , 62 , 67 , 75 ], seven in France [ 51 , 53 , 55 , 63 , 70 , 73 , 78 ], five in Netherland [ 48 , 61 , 66 , 77 , 79 ], three each in both China [ 52 , 65 , 68 ] and Turkey [ 43 , 46 , 82 ], two each in Egypt [ 49 , 76 ], Brazil [ 54 , 81 ], and Italy [ 71 , 83 ], and eight in other countries [ 42 , 57 – 60 , 64 , 69 , 80 ]. The median sample size was 180 recruited participants, with the 21 being the lowest [ 58 ] and 2080 being the highest number of participants [ 61 ] (see Tables 2 , 3 ).…”