“…Detailed descriptions of the included studies are available in additional file 8. Of the 34 studies, 14 were set in the United States [ 35 , 36 , 39 , 43 , 45 , 47 , 49 , 50 , 51 , 56 , 57 , 58 , 59 , 64 ], seven in Canada [ 38 , 46 , 52 , 53 , 54 , 55 , 63 ], five in Australia [ 34 , 41 , 44 , 48 , 62 ], three in the UK [ 40 , 42 , 61 ], three in The Netherlands [ 33 , 37 , 65 ], one in Denmark [ 60 ] and one in which the countries included in the analysis were not explicitly stated [ 66 ].…”