“…Therefore, many studies lacked data concerning some of the parameters. There were insufficient data regarding income in 26 studies ( 22 , 28 , 29 , 31 , 33 , 37 , 38 , 41 , 47 , 48 , 50 , 51 , 53 , 54 , 56 , 60 , 68 - 70 , 72 , 74 , 75 , 80 - 82 ) and educational level in 14 ( 26 , 28 , 30 , 37 , 39 - 41 , 46 , 59 , 61 , 62 , 65 , 68 ) of the 62 reviewed studies (Some of the studies had data on income but not on education, and others had the reverse). Employment and/or occupational status was assessed in 28 studies ( 22 - 24 , 28 , 29 , 31 , 34 - 37 , 39 - 42 , 44 , 45 , 53 , 54 , 58 , 59 , 61 , 67 - 69 , 70 , 77 , 78 , 81 , 82 ).…”