Table 1.

Primary Classification of Youth and Young Adult Studies From TCORS 1.0, CENIC and COMET (September 2013–April 2018), by Study Type, Primary Theme, and FDA Priority^a

Classification	No. of studies (n = 258)
Study type
Systematic Review or Meta-Analysis	15
Longitudinal	46
Experimental	46
Qualitative	79
Observational	141
Primary themes included
Social media	18
Toxicity	22
Health effects	34
Other	34
Addiction	39
Transitions in use	42
Marketing	59
Trajectories of use	60
Dual/poly use	63
Communications	73
Psychosocial risk factors	89
Sociodemographic factors	124
Prevalence of tobacco use	144
Specific tobacco product use	177
FDA priorities directly addressed
Impact analysis	18
Toxicity	22
Health effects	33
Addiction	45
Marketing influences	53
Communications	62
Behavior	206

CENIC = Center for the Evaluation of Nicotine in Cigarettes; COMET = Consortium on Methods Evaluating Tobacco; FDA = Food and Drug Administration; TCORS = Tobacco Centers of Regulatory Science.

^aClassifications of articles in each category are not mutually exclusive.