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Prevalence of substance use among middle school-aged e-cigarette users compared with cigarette smokers, nonusers, and dual users: Implications for primary prevention.

BACKGROUND
The objective of this study was to compare the prevalence of substance use in e-cigarette (EC)-only users with combustible cigarette (CC)-only users, dual users, and nonusers in a large sample of middle school-aged adolescents.


METHODS
Population-based cross-sectional school survey conducted in 15 middle schools in 3 counties in West Virginia in the United States between October and December of 2015 (N = 6547, girls = 49.6%; response rate 84.7%).


RESULTS
Approximately 4.3% of participants had used EC only, 4.5% had used CC only, and around 5.5% were dual users. Nonusers had the lowest prevalence of all 9 forms of substance use assessed in the study (i.e., chewing tobacco, any alcohol, drunkenness, marijuana, sniffing, prescription drugs, hallucinogens, synthetic marijuana, and bath salts), followed by EC and CC users. Dual users had the highest prevalence of 8 of 9 forms of substance use. Multinomial logistic regression models showed that EC-only users had significantly greater odds over nonusers of using 8 of 9 types of substances included in the study. Conversely, EC-only users had significantly lower odds of using 7 of 9 types of substances when compared with dual users. However, EC-only users did not differ from CC-only users in odds of use in any of the 9 substances included in this analysis.


CONCLUSIONS
Among middle school-aged adolescents, EC-only users do not differ from CC-only users in odds for other forms of substance use. Primary prevention programs should consider EC use initiation as a pathway to greater risk of other licit and illicit substances among young adolescents.