“…Fifteen studies were conducted in Asia. Eleven of the studies were in China ( 15 , 22 , 23 , 25 , 29 , 30 , 32 , 33 , 35-37 ), one in Japan ( 31 ), one in India ( 19 ), one in Iran ( 28 ), and one in Pakistan ( 24 ); four studies were conducted in Europe, one in Georgia ( 21 ), one in Belgium ( 17 ), one in the Italian ( 18 ), one in Spain ( 34 ); two studies were performed in the Eurasian country of Turkey ( 16 , 26 ); one study was performed in African Morocco ( 27 ); one study was performed in North America Mexico ( 20 ). All studies were retrospective observation studies, except one was the case-control study ( 15 ).…”