“…Of all the studies, 16 were performed in Europe [5,7,8,10,12,14,[18][19][20][21][22][23][24][25][26][27] , 5 in Asia [9,15,16,28,29] , 4 in North America [11,13,17,30] , 1 in Australia [31] , and 1 in South America [6] (online suppl. material 3 for table of included studies).…”