Initiation of Electronic Cigarette Use by Age Among Youth in the U.S

Introduction: The rapid increase in electronic cigarette (e-cigarette) smoking among U.S. youth requires data regarding the age pattern of initiation risk for effective tobacco use prevention.

Methods: Data from the 2014 National Youth Tobacco Survey (N=20,680, aged 11-19 years, 50.6% male) were analyzed using survival analysis in 2016 to quantify the likelihood of e-cigarette use initiation by age, overall and by gender and racial/ethnic groups.

Results: The estimated mean age of e-cigarette initiation was 17.50 (95% CI=17.47, 17.52) years. The estimated hazards of e-cigarette use initiation were 0 up to age 6 years, increased slowly from age 7 to 11 years, and continued with an accelerated increase up to age 17 years before it slowed down. There were significant gender (male > female) and racial/ethnicity (from high to low: multiracial, white, Hispanic, African, and Asian) differences in the age pattern.

Conclusions: E-cigarette smoking is initiated as young as age 7 years. Different from conventional cigarette smoking with peak initiation risk at age 14-15 years, the likelihood of initiating e-cigarette smoking continues to increase up to age 18 years. The unique age pattern and significant gender and racial/ethnic differences provide useful data to support further research to strengthen tobacco use prevention in the U.S.