Skip to main content
. 2019 May 15;17:41. doi: 10.18332/tid/108614

Table 1.

Characteristics of studies in the systematic review (k=31)

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.