BACKGROUND:

Adolescent use of tobacco in any form is unsafe; yet the use of electronic cigarettes and other electronic vapor products (EVPs) has increased in recent years among this age group. We assessed the prevalence and frequency of cigarette smoking and EVP use among high school students, and associations between health-risk behaviors and both cigarette smoking and EVP use.

METHODS:

We used 2015 national Youth Risk Behavior Survey data (N = 15 624) to classify students into 4 mutually exclusive categories of smoking and EVP use based on 30-day use: nonuse, cigarette smoking only, EVP use only, and dual use. Prevalence of cigarette smoking and EVP use were assessed overall and by student demographics and frequency of use. Prevalence ratios were calculated to identify associations with health risk-behaviors.

RESULTS:

In 2015, 73.5% of high school students did not smoke cigarettes or use EVPs, 3.2% smoked cigarettes only, 15.8% used EVPs only, and 7.5% were dual users. Frequency of cigarette smoking and EVP use was greater among dual users than cigarette-only smokers and EVP-only users. Cigarette-only smokers, EVP-only users, and dual users were more likely than nonusers to engage in several injury, violence, and substance use behaviors; have ≥4 lifetime sexual partners; be currently sexually active; and drink soda ≥3 times/day. Only dual users were more likely than nonusers not to use a condom at last sexual intercourse.

CONCLUSIONS:

EVP use, alone and concurrent with cigarette smoking, is associated with health-risk behaviors among high school students.

What’s Known on This Subject:

Although cigarette smoking among adolescents has decreased, the use of certain emerging tobacco products, such as electronic vapor products (EVPs), has increased. Risks, including health-risk behaviors, associated with EVP use have not yet been fully explored.

What This Study Adds:

EVP use, alone and concurrent with cigarette smoking, is associated with several health-risk behaviors among high school students. This suggests comprehensive efforts to address health-risk behaviors among adolescents are warranted, including prevention strategies focused on all forms of tobacco use.

Cigarette smoking is the leading cause of preventable disease and death in the United States.1,3 Each year in the United States, an estimated 480 000 individuals die of smoking, and >3200 adolescents smoke their first cigarette each day.2 Data from the National Youth Tobacco Survey indicates that cigarette smoking decreased among high school students in the United States during 2011–2015.4 Similarly, data from the Youth Risk Behavior Survey (YRBS) has shown that cigarette smoking among this group is at an all-time low since 1991.5 However, this success is tempered by the finding that use of certain emerging tobacco products, including electronic vapor products (EVPs), has increased.4 This has resulted in no change in overall tobacco use among middle and high school students.4 

EVPs, also known as electronic nicotine delivery systems,6 include electronic cigarettes (e-cigarettes), electronic cigars, electronic pipes, vape pipes or pens, and electronic hookahs or hookah pens. EVPs are handheld devices that provide an aerosol that typically includes nicotine, additives, and other harmful and potentially harmful substances that are inhaled by the user.6,8 Data from the National Youth Tobacco Survey indicate that the percentage of US high school students who reported using an e-cigarette in the past 30 days increased from 1.5% to 16.0% during 2011–2015.4 

There is a range of potential impacts, including risks and possible benefits, of EVPs on patterns of use of cigarettes and other combustible tobacco products among adults.2 However, among youth, any form of tobacco use, including EVPs, is unsafe.2 EVPs typically contain nicotine; nicotine exposure during adolescence can cause addiction, might harm brain development, and could lead to sustained tobacco product use.2,9,10 Furthermore, longitudinal studies suggest that youth who use EVPs are more likely to subsequently initiate cigarette smoking.11,13 The use of multiple tobacco products among adolescents, including EVPs, is also of concern because multiple tobacco product users have greater nicotine dependence than single-product users.14,15 Accordingly, preventing adolescents from initiating the use of any form of tobacco product, including EVPs, is important to tobacco use prevention and control strategies.16 

Given that EVPs are relatively new to the US marketplace, little is known about the use of these products in the context of other health behaviors, which can persist throughout life and contribute to significant morbidity and mortality during adolescence and adulthood.5 Previous research on adolescent tobacco use indicates that cigarette smoking is associated with behaviors related to injury and violence, alcohol and drug use, sexual risk behaviors, physical activity, and school problems (ie, truancy).17,24 Additionally, research suggests that cigarette smoking may be a marker for these and other problem behaviors.23,25 However, the tobacco product landscape continues to diversify, and EVPs are now the most commonly used tobacco products among US high school students, surpassing conventional cigarettes in 2014.26 To date, studies on the association between EVPs and health-risk behaviors among adolescents and young adults has been limited to examining the associations between e-cigarette and substance use. These studies have found that use of e-cigarettes was associated with alcohol use, binge drinking, and marijuana use.12,27,31 

Several studies have assessed the prevalence and reasons for e-cigarette use; however, none have examined associated health-risk behaviors.13,32,33 To address this gap in the literature, this study examined the association between EVPs and a broad range of health-risk behaviors among high school students using data from the national YRBS. This study also compares the frequency of EVP and cigarette use among exclusive and dual users. Given the considerable increases in EVP use and dual tobacco use among adolescents in recent years, the findings from this study could provide critical information to guide public health promotion efforts.

The national YRBS monitors 6 priority health-risk behaviors biennially among high school students.5 The survey uses a 3-stage cluster sample design to obtain a nationally representative sample of public and private school students in grades 9 through 12 in the 50 states and the District of Columbia. Student participation is anonymous and voluntary, and local parental permission procedures are used. The survey is self-administered and students record their responses directly on a computer-scannable questionnaire or answer sheet. Sampling weights are applied to each record to adjust for nonresponse and the oversampling of black and Hispanic students. Additional details regarding YRBS sampling and psychometric properties have been published elsewhere.34,35 In 2015, the YRBS school response rate was 69%, the student response rate was 86%, the overall response rate was 60%, and the sample size was 15 624. The demographic distribution of the 2015 YRBS sample has been published elsewhere.5 An institutional review board at the Centers for Disease Control and Prevention approved the national YRBS.

Cigarette Smoking and EVP Use

Current cigarette smoking and EVP use were assessed with the following 2 questions: “During the past 30 days, on how many days did you smoke cigarettes?” and “During the past 30 days, on how many days did you use an electronic vapor product?” An introduction to the EVP question was provided to give examples of EVP brands (blu, NJOY, or Starbuzz) and examples of EVP types (e-cigarettes, e-cigars, e-pipes, vape pipes, vaping pens, e-hookahs, and hookah pens). Response options for both questions were as follows: 0 days, 1 to 2 days, 3 to 5 days, 6 to 9 days, 10 to 19 days, 20 to 29 days, and all 30 days. These questions were examined in 2 ways. First, each question was used in its original form to examine the number of days students smoked cigarettes and used EVPs (ie, frequency of use). Second, they were combined to create a 4-level variable with mutually exclusive categories: nonuse, cigarette smoking only, EVP use only, and dual use (cigarettes and EVP).

Health-Risk Behaviors

Dependent variables included those related to unintentional injuries and violence, substance use, and sexual risk behaviors (Table 1). Variables in these behavioral domains were included in a previous YRBS analysis that examined associations between tobacco use and health-risk behaviors.21 The current study also assessed dietary behaviors and physical activity (Table 1). The cut points used for fruit and vegetable consumption were based on earlier fruit and vegetable recommendations that used times/day as the measurement unit36 because current fruit and vegetable intake recommendations are reported in cup equivalents/day,37 which cannot be calculated using YRBS data. The soda cutpoint was based on a study of Americans aged 2 years and older, which found that the estimated 90th percentile of daily energy intake from sugar-sweetened beverages was 450 kcal (equivalent to three 12-oz cans of soda).38 The physical activity cutpoint was based on national recommendations.39 

TABLE 1

Question Wording and Analytic Coding for Included Health Risk Behaviors, National YRBS, 2015

Health Risk BehaviorQuestionnaire ItemAnalytic Coding
Injury and violence   
 Text/e-mail while driving During the past 30 days, on how many days did you text or e-mail while driving a car or other vehicle?a ≥1 vs 0 days 
 Engaged in a physical fight During the past 12 months, how many times were you in a physical fight? ≥1 vs 0 times 
 Carried a weapon During the past 30 days, on how many days did you carry a weapon such as a gun, knife, or club? ≥1 vs 0 days 
 Attempted suicide During the past 12 months, how many times did you actually attempt suicide? ≥1 vs 0 times 
Substance use   
 Current alcohol use During the past 30 days, on how many days did you have at least 1 drink of alcohol? ≥1 vs 0 days 
 Current marijuana use During the past 30 days, how many times did you use marijuana? ≥1 vs 0 times 
 Ever synthetic marijuana use During your life, how many times have you used synthetic marijuana (also called K2, Spice, fake weed, King Kong, Yucatan Fire, Skunk, or Moon Rocks)? ≥1 vs 0 times 
 Ever use of other illicit drugs Combines all of the following individual questionnaire items: ≥1 vs 0 times 
 During your life, how many times have you used any form of cocaine, including powder, crack, or freebase? 
 During your life, how many times have you sniffed glue, breathed the contents of aerosol spray cans, or inhaled any paints or sprays to get high? 
 During your life, how many times have you used heroin (also called smack, junk, or China White)? 
 During your life, how many times have you used methamphetamines (also called speed, crystal, crank or ice)? 
 During your life, how many times have you used ecstasy (also called MDMA)? 
 During your life, how many times have you used hallucinogenic drugs, such as LSD, acid, PCP, angel dust, mescaline, or mushrooms? 
 Ever nonmedical use of prescription drugs During your life, how many times have you taken a prescription drug (such as OxyContin, Percocet, Vicodin, codeine, Adderall, Ritalin, or Xanax) without a doctor’s prescription? ≥1 vs 0 times 
Sexual risk behaviors   
 Lifetime sexual partners During your life, with how many people have you had sexual intercourse? ≥4 vs <4 persons 
 Currently sexually active During the past 3 months, with how many people did you have sexual intercourse? ≥1 vs 0 persons 
 Condom use at last sexual intercourse The last time you had sexual intercourse, did you or your partner use a condom?b No vs yes 
Dietary behaviors and physical activity   
 Fruit intake Combines 2 questionnaire items: <2 times/day vs ≥2 times/day 
 During the past 7 days, how many times did you eat fruit? (Do not count fruit juice.) 
 During the past 7 days, how many times did you drink 100% fruit juices such as orange juice, apple juice, or grape juice? (Do not count punch, Kool-Aid, sports drinks, or other fruit-flavored drinks.) 
 Vegetable intake Combines 4 questionnaire items: <3 times/day vs ≥3 times/day 
 During the past 7 days, how many times did you eat green salad? 
 During the past 7 days, how many times did you eat potatoes? (Do not count French fries, fried potatoes, or potato chips.) 
 During the past 7 days, how many times did you eat carrots? 
 During the past 7 days, how many times did you eat other vegetables? (Do not count green salad, potatoes, or carrots.) 
 Soda intake During the past 7 days, how many times did you drink a can, bottle, or glass of a sports drink such as Gatorade or PowerAde? (Do not count low-calorie sports drinks such as Propel or G2.) ≥3 times/day vs <3 times/day 
 Physical activity During the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day? (Add up all the time you spent in any kind of physical activity that increased your heart rate and made you breathe hard some of the time.) <7 days vs 7 days 
Health Risk BehaviorQuestionnaire ItemAnalytic Coding
Injury and violence   
 Text/e-mail while driving During the past 30 days, on how many days did you text or e-mail while driving a car or other vehicle?a ≥1 vs 0 days 
 Engaged in a physical fight During the past 12 months, how many times were you in a physical fight? ≥1 vs 0 times 
 Carried a weapon During the past 30 days, on how many days did you carry a weapon such as a gun, knife, or club? ≥1 vs 0 days 
 Attempted suicide During the past 12 months, how many times did you actually attempt suicide? ≥1 vs 0 times 
Substance use   
 Current alcohol use During the past 30 days, on how many days did you have at least 1 drink of alcohol? ≥1 vs 0 days 
 Current marijuana use During the past 30 days, how many times did you use marijuana? ≥1 vs 0 times 
 Ever synthetic marijuana use During your life, how many times have you used synthetic marijuana (also called K2, Spice, fake weed, King Kong, Yucatan Fire, Skunk, or Moon Rocks)? ≥1 vs 0 times 
 Ever use of other illicit drugs Combines all of the following individual questionnaire items: ≥1 vs 0 times 
 During your life, how many times have you used any form of cocaine, including powder, crack, or freebase? 
 During your life, how many times have you sniffed glue, breathed the contents of aerosol spray cans, or inhaled any paints or sprays to get high? 
 During your life, how many times have you used heroin (also called smack, junk, or China White)? 
 During your life, how many times have you used methamphetamines (also called speed, crystal, crank or ice)? 
 During your life, how many times have you used ecstasy (also called MDMA)? 
 During your life, how many times have you used hallucinogenic drugs, such as LSD, acid, PCP, angel dust, mescaline, or mushrooms? 
 Ever nonmedical use of prescription drugs During your life, how many times have you taken a prescription drug (such as OxyContin, Percocet, Vicodin, codeine, Adderall, Ritalin, or Xanax) without a doctor’s prescription? ≥1 vs 0 times 
Sexual risk behaviors   
 Lifetime sexual partners During your life, with how many people have you had sexual intercourse? ≥4 vs <4 persons 
 Currently sexually active During the past 3 months, with how many people did you have sexual intercourse? ≥1 vs 0 persons 
 Condom use at last sexual intercourse The last time you had sexual intercourse, did you or your partner use a condom?b No vs yes 
Dietary behaviors and physical activity   
 Fruit intake Combines 2 questionnaire items: <2 times/day vs ≥2 times/day 
 During the past 7 days, how many times did you eat fruit? (Do not count fruit juice.) 
 During the past 7 days, how many times did you drink 100% fruit juices such as orange juice, apple juice, or grape juice? (Do not count punch, Kool-Aid, sports drinks, or other fruit-flavored drinks.) 
 Vegetable intake Combines 4 questionnaire items: <3 times/day vs ≥3 times/day 
 During the past 7 days, how many times did you eat green salad? 
 During the past 7 days, how many times did you eat potatoes? (Do not count French fries, fried potatoes, or potato chips.) 
 During the past 7 days, how many times did you eat carrots? 
 During the past 7 days, how many times did you eat other vegetables? (Do not count green salad, potatoes, or carrots.) 
 Soda intake During the past 7 days, how many times did you drink a can, bottle, or glass of a sports drink such as Gatorade or PowerAde? (Do not count low-calorie sports drinks such as Propel or G2.) ≥3 times/day vs <3 times/day 
 Physical activity During the past 7 days, on how many days were you physically active for a total of at least 60 minutes per day? (Add up all the time you spent in any kind of physical activity that increased your heart rate and made you breathe hard some of the time.) <7 days vs 7 days 
a

Excludes students who did not drive a car or other vehicle during the past 30 days.

b

Excludes students who were not currently sexually active.

Covariates

Three demographic characteristics were included in this analysis: sex (male, female), grade (9th, 10th, 11th, and 12th), and race/ethnicity. Students were classified into 4 racial/ethnic categories: white, non-Hispanic; black, non-Hispanic; Hispanic or Latino (of any race); and other or multiple race. The numbers of students in the other or multiple racial/ethnic group were too small for meaningful analysis. The YRBS questionnaire includes questions about 2 other types of tobacco use. Students were also asked their current (past 30-day) use of (1) smokeless tobacco products (chewing tobacco, snuff, or dip) as well as (2) cigars, cigarillos, or little cigars. The response options for these questions were split into 2 groups: any use and no use.

Analyses were conducted on weighted data using SUDAAN (Research Triangle Park, NC), a software package that accounts for the survey’s complex sampling design. The percentage of students in each category of the 4-level combined cigarette and EVP variable was calculated among students overall and by sex, race/ethnicity, and grade. χ2 tests were conducted to assess differences by demographics. Among cigarette users, the frequency of cigarette use was compared between cigarette-only smokers and dual users using pairwise comparisons (t statistic). In parallel, among EVP users, the frequency of EVP use was compared between EVP only and dual users using pairwise comparisons. Additionally, multivariable logistic regression models adjusted for sex, race/ethnicity, grade, smokeless tobacco use, and cigar smoking were used to estimate adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) for the associations between cigarette smoking or EVP use and health-risk behaviors using nonusers as the referent group. PRs were considered statistically significant if 95% CIs did not include 1.0. Lastly, linear contrasts were conducted to compare results for all health-risk behaviors by cigarette and EVP group using other referents (EVP only vs cigarette only, dual use vs cigarette only, and dual use vs EVP only). Differences were considered significant if the P value was < .05.

Nationwide, 73.5% of high school students did not smoke cigarettes or use EVPs, 3.2% smoked cigarettes only, 15.8% used EVPs only, and 7.5% were dual users of both cigarettes and EVPs (Table 2). The distribution across the 4-level cigarette and EVP use variable differed significantly by sex (P = .04), race/ethnicity (P < .001), and grade level (P < .001).

TABLE 2

Prevalence (95% CI) of Cigarette Use and Electronic Vapor Product Use, National YRBS, 2015

DemographicNonuseCigarette OnlyEVP OnlyDual Useχ2 (P)
Overall 73.5 (71.1–75.8) 3.2 (2.6–3.9) 15.8 (14.2–17.5) 7.5 (6.5–8.8)  
Sex     3.1 (.04) 
 Female 75.0 (72.3–77.5) 2.9 (2.2–3.9) 15.4 (13.8–17.1) 6.7 (5.6–8.1)  
 Male 72.0 (69.0–74.8) 3.5 (2.8–4.4) 16.3 (14.1–18.7) 8.3 (7.1–9.6)  
Race/ethnicity     5.5 (<.001) 
 White, non-Hispanic 71.9 (68.2–75.4) 3.6 (2.7–4.6) 15.6 (13.7–17.7) 8.9 (7.1–11.1)  
 Black, non-Hispanic 80.4 (76.1–84.1) 2.9 (1.7–4.9) 13.6 (11.0–16.7) 3.1 (2.1–4.5)  
 Hispanic 71.6 (68.9–74.2) 2.8 (2.1–3.6) 19.2 (17.0–21.6) 6.4 (5.4–7.6)  
Grade     14.8 (<.001) 
 9 79.1 (76.5–81.5) 1.8 (1.2–2.7) 13.4 (11.2–15.9) 5.7 (4.2–7.7)  
 10 75.2 (71.6–78.4) 2.3 (1.7– 3.1) 16.1 (13.9–18.5) 6.4 (5.0–8.2)  
 11 70.5 (67.2–73.5) 4.4 (3.4–5.7) 16.6 (14.1–19.5) 8.5 (6.9–10.3)  
 12 68.4 (64.6–71.9) 4.4 (3.3–6.0) 17.6 (15.1–20.4) 9.6 (7.8–11.7)  
DemographicNonuseCigarette OnlyEVP OnlyDual Useχ2 (P)
Overall 73.5 (71.1–75.8) 3.2 (2.6–3.9) 15.8 (14.2–17.5) 7.5 (6.5–8.8)  
Sex     3.1 (.04) 
 Female 75.0 (72.3–77.5) 2.9 (2.2–3.9) 15.4 (13.8–17.1) 6.7 (5.6–8.1)  
 Male 72.0 (69.0–74.8) 3.5 (2.8–4.4) 16.3 (14.1–18.7) 8.3 (7.1–9.6)  
Race/ethnicity     5.5 (<.001) 
 White, non-Hispanic 71.9 (68.2–75.4) 3.6 (2.7–4.6) 15.6 (13.7–17.7) 8.9 (7.1–11.1)  
 Black, non-Hispanic 80.4 (76.1–84.1) 2.9 (1.7–4.9) 13.6 (11.0–16.7) 3.1 (2.1–4.5)  
 Hispanic 71.6 (68.9–74.2) 2.8 (2.1–3.6) 19.2 (17.0–21.6) 6.4 (5.4–7.6)  
Grade     14.8 (<.001) 
 9 79.1 (76.5–81.5) 1.8 (1.2–2.7) 13.4 (11.2–15.9) 5.7 (4.2–7.7)  
 10 75.2 (71.6–78.4) 2.3 (1.7– 3.1) 16.1 (13.9–18.5) 6.4 (5.0–8.2)  
 11 70.5 (67.2–73.5) 4.4 (3.4–5.7) 16.6 (14.1–19.5) 8.5 (6.9–10.3)  
 12 68.4 (64.6–71.9) 4.4 (3.3–6.0) 17.6 (15.1–20.4) 9.6 (7.8–11.7)  

Dual users of cigarettes and EVPs were significantly less likely than cigarette-only smokers to smoke cigarettes 1 to 2 days (32.8% vs 46.0%) but significantly more likely to smoke cigarettes 10 to 19 days (10.7% vs 5.3%) and 20 to 29 days (12.3% vs 4.1%) (Fig 1). Dual users of cigarettes and EVPs were significantly less likely than EVP-only users to use EVPs 1 to 2 days (29.2% vs 55.6%), but significantly more likely to use EVPs 6 to 9 days (14.7% vs 9.1%), 10 to 19 days (15.3% vs 7.5%), 20 to 29 days (5.8% vs 3.1%), and all 30 days (13.0% vs 5.3%) (Fig 2).

FIGURE 1

Cigarette smoking frequency among cigarette only smokers and dual users, National YRBS, 2015. “Dual user” is defined as a student who currently smokes cigarettes and uses electronic vapor products. *Statistical difference between cigarette-only smokers and dual users.

FIGURE 1

Cigarette smoking frequency among cigarette only smokers and dual users, National YRBS, 2015. “Dual user” is defined as a student who currently smokes cigarettes and uses electronic vapor products. *Statistical difference between cigarette-only smokers and dual users.

FIGURE 2

EVP use frequency among EVP-only users and dual users, National YRBS, 2015. “Dual user” is defined as a student who currently smokes cigarettes and uses electronic vapor products. *Statistical difference between EVP only users and dual users.

FIGURE 2

EVP use frequency among EVP-only users and dual users, National YRBS, 2015. “Dual user” is defined as a student who currently smokes cigarettes and uses electronic vapor products. *Statistical difference between EVP only users and dual users.

Unintentional Injuries and Violence

Cigarette-only smokers, EVP-only users, and dual users were significantly more likely than nonusers to engage in a physical fight (PR range: 1.72–2.87) and attempt suicide (PR range: 1.86–4.01) (Table 3). Both EVP-only users and dual users were significantly more likely than nonusers to text or e-mail while driving (PR: 1.39 and 1.41, respectively). Only dual users were significantly more likely than nonusers to carry a weapon (PR: 1.82; 95% CI: 1.30–2.56).

TABLE 3

Risk of Health Risk Behaviors by Cigarette Smoking and EVP Use, National YRBS, 2015

Health Risk Behavior%Nonuse%Cigarette Smoking Only%EVP Use Only%Dual Usea
PRPR (95% CI)PR (95% CI)PR (95% CI)
Injury and violence         
 Text/e-mail while drivingb 34.4 Ref 53.4 1.19 (0.94–1.49) 52.7 1.39 (1.26–1.53) 62.7 1.41 (1.21–1.64) 
 Engaged in a physical fightc 16.5 Ref 36.3 1.88 (1.52–2.33) 29.6 1.72 (1.53–1.93) 55.2d,e 2.87 (2.53–3.26) 
 Carried a weaponb 2.5 Ref 8.0 1.48 (0.84–2.59) 4.9 1.45 (0.99–2.12) 12.0 1.82 (1.30–2.56) 
 Attempted suicidec 5.7 Ref 18.5 3.46 (2.51–4.77) 10.5f 1.86 (1.53–2.25) 23.3e 4.01 (3.17–5.08) 
Substance use         
 Current alcohol useb 18.7 Ref 72.7 2.67 (2.22–3.20) 61.9 2.62 (2.39–2.87) 86.4d,e 3.29 (2.88–3.77) 
 Current marijuana useb 9.9 Ref 51.4 3.49 (2.80–4.36) 43.7 3.70 (3.16–4.32) 69.7d,e 5.22 (4.42–6.18) 
 Ever synthetic marijuana use 3.2 Ref 26.1 5.39 (3.84–7.58) 14.5f 3.67 (3.04–4.44) 40.2d,e 8.65 (6.60–11.35) 
 Ever use of other illicit drugsg 6.1 Ref 29.2 3.23 (2.17–4.83) 19.8 2.73 (2.25–3.30) 50.7d,e 5.75 (4.48–7.40) 
 Ever nonmedical use of prescription drugs 9.3 Ref 36.1 2.66 (2.04–3.48) 24.8 2.30 (1.97–2.68) 54.9d,e 4.13 (3.44–4.96) 
Sexual risk behaviors         
 Four or more lifetime sexual partners 6.1 Ref 33.8 3.84 (2.86–5.16) 16.9f 2.35 (1.93–2.87) 39.0e 4.60 (3.64–5.81) 
 Current sexual activityh 21.5 Ref 56.3 1.93 (1.64–2.28) 46.2 1.86 (1.65–2.10) 63.8e 2.30 (1.91–2.78) 
 Did not use a condom at last sexual intercoursei 41.5 Ref 48.4 1.17 (0.93–1.49) 38.1 0.93 (0.82–1.05) 52.2e 1.27 (1.07–1.50) 
Dietary behaviors and physical activityj         
 Fruit <2 times/d 69.4 Ref 71.5 1.05 (0.96–1.14) 65.7 0.95 (0.90–1.01) 66.8 0.99 (0.93–1.06) 
 Vegetables <3 times/d 86.6 Ref 82.8 0.98 (0.94–1.02) 84.5 0.98 (0.95–1.01) 79.0 0.94 (0.91–0.98) 
 Soda ≥3 times/d 5.3 Ref 15.3 2.66 (1.79–3.95) 7.6f 1.35 (1.04–1.76) 18.1e 3.03 (2.26–4.05) 
 <7 d of physical activity 74.1 Ref 76.4 1.07 (1.00–1.15) 66.7f 0.91 (0.88–0.95) 69.5e 1.01 (0.96–1.07) 
Health Risk Behavior%Nonuse%Cigarette Smoking Only%EVP Use Only%Dual Usea
PRPR (95% CI)PR (95% CI)PR (95% CI)
Injury and violence         
 Text/e-mail while drivingb 34.4 Ref 53.4 1.19 (0.94–1.49) 52.7 1.39 (1.26–1.53) 62.7 1.41 (1.21–1.64) 
 Engaged in a physical fightc 16.5 Ref 36.3 1.88 (1.52–2.33) 29.6 1.72 (1.53–1.93) 55.2d,e 2.87 (2.53–3.26) 
 Carried a weaponb 2.5 Ref 8.0 1.48 (0.84–2.59) 4.9 1.45 (0.99–2.12) 12.0 1.82 (1.30–2.56) 
 Attempted suicidec 5.7 Ref 18.5 3.46 (2.51–4.77) 10.5f 1.86 (1.53–2.25) 23.3e 4.01 (3.17–5.08) 
Substance use         
 Current alcohol useb 18.7 Ref 72.7 2.67 (2.22–3.20) 61.9 2.62 (2.39–2.87) 86.4d,e 3.29 (2.88–3.77) 
 Current marijuana useb 9.9 Ref 51.4 3.49 (2.80–4.36) 43.7 3.70 (3.16–4.32) 69.7d,e 5.22 (4.42–6.18) 
 Ever synthetic marijuana use 3.2 Ref 26.1 5.39 (3.84–7.58) 14.5f 3.67 (3.04–4.44) 40.2d,e 8.65 (6.60–11.35) 
 Ever use of other illicit drugsg 6.1 Ref 29.2 3.23 (2.17–4.83) 19.8 2.73 (2.25–3.30) 50.7d,e 5.75 (4.48–7.40) 
 Ever nonmedical use of prescription drugs 9.3 Ref 36.1 2.66 (2.04–3.48) 24.8 2.30 (1.97–2.68) 54.9d,e 4.13 (3.44–4.96) 
Sexual risk behaviors         
 Four or more lifetime sexual partners 6.1 Ref 33.8 3.84 (2.86–5.16) 16.9f 2.35 (1.93–2.87) 39.0e 4.60 (3.64–5.81) 
 Current sexual activityh 21.5 Ref 56.3 1.93 (1.64–2.28) 46.2 1.86 (1.65–2.10) 63.8e 2.30 (1.91–2.78) 
 Did not use a condom at last sexual intercoursei 41.5 Ref 48.4 1.17 (0.93–1.49) 38.1 0.93 (0.82–1.05) 52.2e 1.27 (1.07–1.50) 
Dietary behaviors and physical activityj         
 Fruit <2 times/d 69.4 Ref 71.5 1.05 (0.96–1.14) 65.7 0.95 (0.90–1.01) 66.8 0.99 (0.93–1.06) 
 Vegetables <3 times/d 86.6 Ref 82.8 0.98 (0.94–1.02) 84.5 0.98 (0.95–1.01) 79.0 0.94 (0.91–0.98) 
 Soda ≥3 times/d 5.3 Ref 15.3 2.66 (1.79–3.95) 7.6f 1.35 (1.04–1.76) 18.1e 3.03 (2.26–4.05) 
 <7 d of physical activity 74.1 Ref 76.4 1.07 (1.00–1.15) 66.7f 0.91 (0.88–0.95) 69.5e 1.01 (0.96–1.07) 

PRs (adjusted for sex, race/ethnicity, grade, smokeless tobacco use, and cigar smoking): comparisons are considered significant if 95% CIs do not include 1.0. Linear contrasts: differences are considered significant if P < .05 for the contrast. Significant differences are noted on the prevalence estimates.

a

“Dual use” is defined as currently smoking cigarettes and using EVPs.

b

During the 30 d before the survey.

c

During the 12 mo before the survey.

d

Linear contrast is significant for dual use vs cigarette smoking only.

e

Linear contrast is significant for dual use vs EVP use only.

f

Linear contrast is significant for EVP use only vs cigarette smoking only.

g

Cocaine, inhalants, heroin, methamphetamines, ecstasy, and hallucinogenic drugs.

h

During the 3 mo before the survey.

i

Analyzed among students who were currently sexually active.

j

During the 7 d before the survey.

Substance Use Behaviors

Cigarette-only smokers, EVP-only users, and dual users were significantly more likely than nonusers to currently drink alcohol (PR range: 2.62–3.29), currently use marijuana (PR range: 3.49–5.22), ever use synthetic marijuana (PR range: 3.67–8.65), ever use other illicit drugs (PR range: 2.73–5.75), and report ever nonmedical use of prescription drugs (PR range: 2.30–4.13) (Table 3).

Sexual Risk Behaviors

Cigarette-only smokers, EVP-only users, and dual users were significantly more likely than nonusers to have ≥4 lifetime partners (PR range: 2.35–4.60) and be currently sexually active (PR range: 1.86–2.30) (Table 3). Only dual users were significantly more likely than nonusers not to use a condom at last sexual intercourse (PR: 1.27; 95% CI: 1.07–1.50).

Dietary Behaviors and Physical Activity

Dual users were significantly less likely to eat vegetables <3 times per day compared with nonusers (PR: 0.94; 95% CI: 0.91–0.98) (Table 3). Cigarette-only smokers, EVP-only users, and dual users were significantly more likely than nonusers to drink soda ≥3 times/day (PR range: 1.35–3.03). EVP-only users were significantly less likely not to engage in daily physical activity compared with nonusers (PR: 0.91; 95% CI: 0.88–0.95).

Linear Contrasts

Engaging in health-risk behaviors did not generally differ between EVP-only users and cigarette-only smokers (Table 3); however, cigarette-only smokers were significantly more likely than EVP-only users to attempt suicide, ever use synthetic marijuana, have ≥4 lifetime sexual partners, drink soda ≥3 times/day, and be physically active <7 days in the 7 days before the survey. When comparing dual users to cigarette-only smokers, dual users were significantly more likely than cigarette-only smokers to engage in all substance use behaviors and physical fighting. When comparing dual users to EVP-only users, significant differences were observed for all substance use and sexual risk behaviors, physical fighting, attempted suicide, soda intake, and physical activity. In all cases, dual users were more likely to engage in these behaviors compared with EVP-only users.

The findings of this study are consistent with other studies documenting an association between EVP use, particularly e-cigarettes, and other substance use.12,27,31 However, this study also shows that EVP use is associated with other health-risk behaviors. For a majority of the behaviors examined in this study, cigarette-only smokers and EVP-only users were as likely to engage in that behavior, suggesting that the associations between health-risk behaviors and EVP use mirror the associations between health-risk behaviors and conventional cigarettes. The pattern of cigarette-only and EVP-only users having intermediate risks between nonusers and dual users is consistent with other published studies.29,30 Consequently, addressing the diversity of tobacco use as part of youth health promotion efforts is important.

Research on conventional cigarettes suggests that smoking occurs along with, or clusters with, various health-risk behaviors and that cigarette smoking may serve as a marker for these behaviors.17,25 This is important to consider in the context of public health practice because research indicates that among adults, the odds of reporting fair or poor health status increase with each unhealthy behavior that an individual engages in.40 The development of certain unhealthy behaviors during adolescence puts adolescents on trajectories toward chronic disease.25 The reason for the association between tobacco use and other health-risk behaviors may be due to common factors (ie, lack of resources such as health education), motivation by similar goals (ie, rejecting conventional social norms), or the activation of similar neural pathways.24,25,41 Cigarette smoking has also been found to be associated with emotional and behavioral problems, which could also make adolescents more vulnerable to developing other health-risk behaviors.42,43 Future studies may show similar vulnerabilities among EVP users, including whether e-cigarette use may be introducing youth with relatively low-risk profiles to substance use. Therefore, comprehensive efforts to address the health-risk behaviors among adolescents are warranted, including prevention strategies focused on all forms of tobacco use, including EVPs.

Despite the harms of EVP use among adolescents, use of these products among US middle and high school students has increased considerably in recent years, for several possible reasons. First, in 2014, 18 million youth were exposed to e-cigarette advertising.44 Given the link between marketing of conventional tobacco products and tobacco initiation among youth, it is likely that increases in e-cigarette marketing are contributing to increases in EVP use.44 Second, the flavorings frequently used in EVPs are appealing to adolescents.6,8,45 Third, use of EVPs may be considered more socially acceptable, particularly in indoor areas where conventional cigarette smoking is prohibited.6 Fourth, EVPs have been relatively easy for youth to access; they are available in retail stores, mall kiosks, and the Internet.6,46 However, efforts are underway to reduce potential public harms of these products through regulation. In May 2016, the US Food and Drug Administration finalized a rule extending its authority to all products that meet the definition of a tobacco product, including e-cigarettes. E-cigarettes are considered a tobacco product due to a 2011 court ruling.47 The 2016 rule sets a national minimum age for sales, requires tobacco product ingredient reporting and reporting of harmful and potentially harmful constituents, and ensures Food and Drug Administration premarket review of new and changed tobacco products.48 

This study found that dual users smoked cigarettes more frequently than cigarette-only smokers and used EVPs more frequently than EVP-only users. These findings are consistent with research showing that among US adolescents who ever smoked cigarettes, e-cigarette users were less likely than nonusers to abstain from cigarettes.49 Additionally, a study of Polish adolescents found that dual users of electronic and conventional cigarettes were more likely to smoke cigarettes daily and less likely to smoke fewer cigarettes per day than students who exclusively smoked conventional cigarettes.50 This lack of decline in smoking frequency among youth e-cigarette users is contrary to studies showing that EVP use may reduce cigarette smoking frequency among adults.51 These findings underscore the importance of evidence-based measures to prevent use of all forms of tobacco use, including experimental or intermittent use, among youth.52 Studies have shown that symptoms of tobacco dependence are evident even among adolescents who used only a single tobacco product on as few as 1 to 2 days during the previous month.15 

In addition to population-based interventions, such as youth access restrictions and comprehensive smoke-free policies that include EVPs,53 actions can also be taken in the clinical setting to address youth tobacco use. Screening of patients and their caregivers for EVP use can be incorporated into tobacco use screening.6 Counseling about the harms associated with adolescent tobacco use, including EVP use, is critical.6 It is particularly important that this counseling identify and correct misperceptions about the use of EVP products in this population.40 

This study has at least 4 limitations. First, YRBS data are self-reported, and students may misreport their behaviors. Although the EVP question is new to YRBS, a psychometric study has shown that the YRBS questions generally have good test-retest reliability.34 Second, the data are from an observational study; therefore, causality cannot be determined. Third, some of the behaviors investigated may not be risky for particular individuals under certain circumstances. For example, sexual intercourse without a condom may not be risky for mutually monogamous partners when another contraceptive method is used. Lastly, data are only collected on adolescents who attend school and therefore are not representative of all individuals in this age group. However, nationwide in 2012, ∼3% of persons aged 16 to 17 years were not enrolled in a high school program and had not completed high school.54 

EVP use, alone and concurrent with cigarette smoking, is associated with health-risk behaviors among high school students. Moreover, dual users of EVPs and conventional cigarettes reported using these products more frequently than exclusive users of these products. These findings underscore the importance of comprehensive efforts to address health-risk behaviors among adolescents, including prevention strategies focused on all forms of tobacco use, including EVPs. Additionally, educational and counseling efforts focusing on the harms associated with adolescent tobacco use, including EVPs, are critical.

     
  • CI

    confidence interval

  •  
  • EVP

    electronic vapor product

  •  
  • PR

    prevalence ratio

  •  
  • YRBS

    Youth Risk Behavior Survey

Dr Demissie conceptualized and designed the study, performed the data analysis, interpreted the study findings, and drafted the initial manuscript; Drs Everett Jones and Clayton conceptualized and designed the study, provided interpretation of the data, and reviewed and revised the manuscript; Dr King provided interpretation of the data and reviewed and revised the manuscript; and all authors approved the final manuscript as submitted.

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the US Public Health Service Commissioned Corps.

FUNDING: No external funding.

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Competing Interests

POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose.

FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.