“…Moreover, to establish the same criteria and time frame for a lifetime, current, and dual e-cigarette use, we have defined lifetime use as “having ever used e-cigarettes, even just once,” current use as “the use of a tobacco product on at least one day in the past 30 days,” and dual use as “the use of both products (i.e., cigarette and e-cigarette) within the same reporting period (e.g., the past 30 days)” [ 40 ]. After these stages, a total of 53 articles were chosen for analysis ( Figure 1 ) [ 1 , 4 , 5 , 8 , 9 , 11 , 23 , 28 , 29 , 30 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , …”