Abstract
INTRODUCTION: Electronic cigarettes are now the most commonly used form of tobacco product among youth in the United States. Current evidence suggests that although e-cigarettes are perceived as less harmful and preferred over combustible cigarettes by adolescents, adolescents who try e-cigarettes are at greater risk of transitioning to combustible cigarettes. The genetic and environmental contributions to liability for e-cigarette use have not yet been examined using a behavioral genetic design. METHODS: Behavioral genetic models of lifetime and current e-cigarette use and friends who use e-cigarettes were examined among female monozygotic and dizygotic twins. RESULTS: A total of 41 female twin pairs (65.9% monozygotic twins; age = 19.7, SD = 1.6) with complete data on the study variables were included in the present analyses. The majority of the sample (68.1%) had at least some friends who use e-cigarettes. Additive genetic effects on e-cigarette use were not present, but the shared environment explained 98.7% of the variance in lifetime e-cigarette use, 96.6% in current e-cigarette use, and 94.9% in affiliation with friends who use e-cigarettes. CONCLUSION: This first study on the behavioral genetics of e-cigarette use among adolescents and young adults suggest that environmental factors shared by twins within a family seem to play a predominant role in the initial stages of e-cigarette use, a finding that is consistent with what has been found for tobacco. The findings emphasize the importance of continuing population-based tobacco control interventions to reduce the burden of e-cigarette use among adolescents. IMPLICATIONS: The shared environment significantly influences the initiation and regular use of electronic cigarettes and affiliation with friends who use electronic cigarettes among adolescent and young adult females. These findings underscore the importance of formulating preventive interventions that mitigate the social effects of familial influences on e-cigarette use through social skills training, education on harms of e-cigarettes for young people, or altering social norms regarding initiation of novel tobacco products.