Table 1.
Variable | k | % |
---|---|---|
Age groups | ||
Adolescents only | 14 | 45 |
Young adults only | 13 | 42 |
Adolescents & young adults | 4 | 13 |
Cigarette smoking status | ||
Smokers | 9 | 29 |
Non-smokers | 1 | 3 |
Smokers and non-smokers | 21 | 68 |
Smokeless tobacco use | ||
Smokeless tobacco | 6 | 19 |
NR | 26 | 84 |
Country | ||
USA | 20 | 65 |
Canada | 4 | 13 |
Germany | 2 | 6 |
Other countries each studied once (Bangladesh, China, France, Greece, India, Lebanon, Mexico, The Netherlands, Spain, Switzerland) | 10 | 32 |
Sampling | ||
Probability | 3 | 10 |
Convenience | 28 | 90 |
Many numbers add up to over k=31 or over 100% because some studies included multiple options for each characteristic. Some studies were conducted in multiple countries. NR: not reported.