Sample characteristics | N | US* studies (n=23) | Non-US† studies (n=17) |
---|---|---|---|
Product type | |||
E-cigarette | 17 | 10 | 7 |
Cigarette | 10 | 4 | 6 |
Little cigar, cigarillo, cigar | 4 | 2 | 2 |
Hookah | 3 | 2 | 1 |
Various tobacco products | 3 | 2 | 1 |
Smokeless tobacco | 2 | 2 | 0 |
Bidi | 1 | 1 | 0 |
Outcome measures‡ | |||
Taste, appeal, risk perceptions | 11 | 4 | 7 |
Preference | 10 | 4 | 6 |
Expectancies and beliefs | 6 | 3 | 3 |
Reasons for use | 7 | 5 | 2 |
Intention to try, initiation | 12 | 7 | 5 |
Progression to regular use | 2 | 1 | 1 |
Dual/poly use | 3 | 2 | 1 |
Quit intention and quitting behaviour | 4 | 2 | 2 |
*One study included participants (13%) outside the USA.20
†One study included participants (41%) from the USA.21
‡Categories are not mutually exclusive.