Document Type

Capstone Experience

Graduation Date


Degree Name

Master of Public Health



First Committee Member

Hongying (Daisy) Dai

Second Committee Member

Carrie McAdam Marx

Third Committee Member

Fang Qiu


Purpose: Tobacco product susceptibility is defined as the interest a person has to start smoking. Tobacco product initiation refers to whether a person has ever used tobacco products. We aim to understand and explain how genetic and environmental factors affect tobacco products' susceptibility and initiation in children. Methods: The classical twin model estimates three sources of variance: additive genetic (A), shared environmental (C), and unique environments (E). Each source of variance is latent and is calculated from the similarity in the correlations of twin pairs on a phenotype. The magnitude of difference in the correlation of a particular phenotype by zygosity is used to attribute additive genetic or shared environmental sources of variance. Data for this study were obtained from The Adolescent Brain Cognitive Development (ABCD) study. Results/Findings: A total of 884 twin pairs with study variables data were included in the present analyses. We estimate how much the variation in a phenotype is due to additive genetic effects (A), the common environment (C), and the unique, random environment (E) by SAS software. Tobacco products' susceptibility is primarily influenced by environmental factors, especially one’s unique factors (C2=37%, pConclusion: This study suggests that environmental factors, incredibly unique environments, impact tobacco product susceptibility, and there is an additive genetic liability combined with environmental factors that can explain tobacco product initiation at an early age. This result advocates intervention strategies focusing on the unique environment to decrease children’s smoking susceptibility and calls for more studies on the genetic components of smoking initiation.