Date of Award

Spring 2022

Degree Type



Epidemiology and Biostatistics

Director of Thesis

Anthony Alberg, Ph.D.

First Reader

John Hartsell, MS-MPH

Second Reader

John Hartsell, MS-MPH


Background - Studies have shown that electronic nicotine delivery systems (ENDS) are unsafe for consumption. However, the prevalence of e-cigarette use among adolescents and young adults continues to increase, which is being addressed by research. Little attention has been paid to the effects of earlier age of ENDS initiation.

Purpose - This paper examined published research studies on the topic of the age of initiation of e-cigarette use in relation to 1) frequency of e-cigarette use and 2) risk of combustible tobacco cigarette smoking initiation. This research tested the hypothesis that an earlier age of e-cigarette initiation was associated with increased frequency of use and increased risk for combustible tobacco cigarette smoking.

Methods - A systematic review was performed by ascertaining, analyzing and interpreting published peer-reviewed articles obtained from PubMed’s MEDLINE database. Peer-reviewed articles containing keywords related to the research question were filtered based on inclusion criteria and data were organized in evidence tables to synthesize the evidence on this topic.

Results - Three cross-sectional studies and two longitudinal studies were included in the review. Two of the studies showed that earlier age of initiation of e-cigarettes was associated with greater frequency of use, but one study found no association. Three studies found that earlier age of initiation was associated with increased risk of cigarette smoking.

Conclusion - Findings tended to support the hypothesis that a younger age of initiation would lead to more frequent e-cigarette use and risk of cigarette smoking initiation. Due to a limited number of eligible articles, further research regarding the age of e-cigarette initiation would be helpful to better draw conclusions with longitudinal data. The implications of these findings are that future public health and government interventions can focus their efforts on decreasing exposure of young people to e-cigarette products to prevent further increases in prevalence and intensity. The importance in this research is that delaying the age of initiation can have public health benefits, even without changes in prevalence.

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© 2022, Andy Hu