“…The studies were published over a 12-year period from 2009 to 2012. There were 14 studies from the USA [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]; eight studies from China [ 6 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]; four studies from the European region [ 37 , 38 , 39 , 40 ]; two studies from Canada [ 41 , 42 ]; two studies from Australia [ 43 , 44 ]; and one study from Peru [ 45 ].…”