Fig. 2

Methodological quality and study characteristics. References: a. Fair quality: [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42]. Good quality: [43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70]. b [28]. and [57]. c. Americas [8,9,10,11,12,13,14,15,16, 28,29,30,31,32,33,34, 43,44,45,46,47,48,49, 58], Europe [17,18,19,20,21,22,23, 35,36,37,38, 50,51,52, 57, 59,60,61,62,63], Asia [24,25,26, 39,40,41, 53,54,55, 64,65,66,67,68,69], Oceania [27, 56, 70] and Africa [42]. d. Brazil [8, 11, 13,14,15,16, 29, 33, 34, 43,44,45, 49], United States [9, 10, 12, 30,31,32, 46, 47, 58], Korea [26, 40, 41, 55, 64,65,66,67,68], Japan [24, 25, 53, 69], France [18, 61,62,63], England [19,20,21, 35], Germany [17, 23, 59], Denmark [37, 52, 60], Australia [27, 56, 70], Thailand [39, 54], United Kingdom [22, 57], Nigeria [42], Canada [28], Mexico [48], Laos [39], Spain [38], Sweden [36], and Switzerland [51]