“…A large proportion of included studies were conducted within the United States, 30 , 36 , 43 , 45 , 46 , 48 , 50 , 51 , 56 , 58 , 59 , 63 with other studies originating in Iran, 34 , 61 India, 31 , 62 China, 38 , 60 Turkey, 39 , 44 the United Kingdom, 64 Germany, 41 , 55 Taiwan, 47 , 54 Hong Kong, 35 the Netherlands, 37 Denmark, 40 Canada, 29 Portugal, 52 Thailand, 49 Greece, 53 Australia, 42 and Italy. 57 Sample sizes ranged from 38 to 652 participants, aged 18 years and older, with an equal proportion of men and women, except for obstetric studies.…”