Journal of Adolescent Health 56 (2015) 557e563
www.jahonline.org Original article
Alcohol Mixed With Energy Drink Use Among U.S. 12th-Grade Students: Prevalence, Correlates, and Associations With Unsafe Driving Meghan E. Martz, M.S. a, b, *, Megan E. Patrick, Ph.D. a, and John E. Schulenberg, Ph.D. a, b a b
Institute for Social Research, University of Michigan, Ann Arbor, Michigan Developmental Psychology Department, University of Michigan, Ann Arbor, Michigan
Article history: Received August 19, 2014; Accepted January 26, 2015 Keywords: Alcohol mixed with energy drinks (AmED); Alcohol; Energy drink; Drinking; High school students; Driving
A B S T R A C T
Purpose: The consumption of alcohol mixed with energy drinks (AmED) is a risky drinking behavior, most commonly studied using college samples. We know little about rates of AmED use and its associations with other risk behaviors, including unsafe driving, among high school students. This study examined the prevalence and correlates of AmED use among high school seniors in the United States. Methods: Nationally representative analytic samples included 6,498 12th-grade students who completed Monitoring the Future surveys in 2012 and 2013. Focal measures included AmED use, sociodemographic characteristics, academic and social factors, other substance use, and unsafe driving (i.e., tickets/warnings and accidents) after alcohol consumption. Results: Approximately one in four students (24.8%) reported AmED use during the past 12 months. Rates of AmED use were highest among males and white students. Using multivariable logistic regression models controlling for sociodemographic characteristics, results indicate that students who cut class, spent more evenings out for fun and recreation, and reported binge drinking, marijuana use, and illicit drug use had a greater likelihood of AmED use. AmED use was also associated with greater odds of alcohol-related unsafe driving, even after controlling for sociodemographic, academic, and social factors and other substance use. Conclusions: AmED use among 12th-grade students is common and associated with certain sociodemographic, academic, social, and substance use factors. AmED use is also related to alcoholrelated unsafe driving, which is a serious public health concern. Ó 2015 Society for Adolescent Health and Medicine. All rights reserved.
Conflicts of Interest: The authors report no potential, perceived, or real conflicts of interest. Disclaimer: The content here is solely the responsibility of the authors and does not necessarily represent the official views of the sponsors. The study sponsor had no role in (1) study design; (2) the collection, analysis, and interpretation of data; (3) the writing of the report; or (4) the decision to submit the article for publication. * Address correspondence to: Meghan E. Martz, M.S., University of Michigan Developmental Psychology Department, University of Michigan, 2044 East Hall, 530 Church Street, Ann Arbor, MI 48109. E-mail address: [email protected] (M.E. Martz). 1054-139X/Ó 2015 Society for Adolescent Health and Medicine. All rights reserved. http://dx.doi.org/10.1016/j.jadohealth.2015.01.019
IMPLICATIONS AND CONTRIBUTION
Research on alcohol mixed with energy drink use has focused predominantly on college students. The present study, using nationally representative samples of high school seniors, shows that this potentially dangerous drinking behavior occurs earlier during high school and is associated with other risky behaviors, including alcohol-related unsafe driving.
The use of alcohol mixed with energy drinks (AmED) has emerged as a high-risk drinking behavior, especially among youth. Although the U.S. Food and Drug Administration banned the sale of premixed alcoholic energy drinks in 2010 after deeming caffeine an “unsafe food additive” for alcoholic beverages [1], AmED use is relatively common. Most studies examining AmED consumption have predominately used college samples, finding prevalence rates ranging from 20%e25% [2e5]. In one of the few studies using a high school student sample, Azagba et al. [6] found that more than one third of Canadian high school seniors reported AmED use within the past year. In
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another study using a panel sample of youth drinkers, 7.4% of 16- to 18-year-olds reported AmED use within the past 30 days [7]. High schooleaged youth appear to be engaging in AmED use; yet, nationally representative prevalence rates and correlates among youth in the United States remain unknown. This is troublesome, considering that adolescents are especially vulnerable to risky drinking behaviors [8,9]. A serious danger of AmED use is that the stimulant effects of caffeine may be perceived as offsetting the depressant effects of alcohol, resulting in individuals feeling less intoxicated than they actually are [10e12]. Researchers have described this as “wide awake drunkenness” [13]. Thus, energy drinks may be used with the intent to diminish the depressant effects of alcohol. For example, college students’ motivations for AmED use include being able to drink more, getting drunk faster, and feeling less tired when drinking [12]. Not only does the discrepancy between perceived and actual intoxication contribute to drinking past the point of intoxication, but also it is associated with increased risktaking behavior [2,7,11,14]. College students classified as moderate drinkers with a high proportion of drinking occasions involving AmED use reported more physical consequences, including hangovers, blackouts, and vomiting compared with moderate drinkers with low AmED use [15]. Likewise, in a study that investigated consequences of AmED use through daily surveys of college students, students experienced more negative consequences and reported drinking greater amounts of alcohol on days when they consumed alcohol and energy drinks, compared with days when they consumed only alcohol [14]. AmED use is also associated with impaired driving, although this research is again limited to college students and adult samples [3,5,16,17]. Consuming AmED may contribute to driving after drinking because of the subjective perception that caffeine offsets the effects of alcohol that impair coordination and attention. College students who engaged in more frequent AmED use have been found to report significantly greater odds of driving after drinking, even after controlling for age, gender, binge drinking, and risk-taking propensity [3]. In a study testing subjective versus objective measures of alcohol intoxication, young adults reported feeling that they had less impaired motor coordination when they consumed AmED compared with when they consumed only alcohol [11]. Despite subjects’ perceptions of reduced effects of intoxication, AmED use did not improve objective measures of motor coordination or visual reaction time. Additionally, breath alcohol concentration remained unaffected by AmED use. In fact, in a study that tested driving performance using a driving simulator task, AmED use was associated with a greater number of speed fluctuations, lateral movements, and increased crashes compared with consuming alcohol without the addition of energy drinks [17]. To our knowledge, no studies to date have investigated the association between AmED use and unsafe driving among high school students. Research is needed to test this association for three key reasons. First, high school students are likely less experienced drivers. Second, the risk of motor vehicle crashes in the United States is highest among adolescents aged 16e19 years compared with any other age group [18]. Third, substance use is a known risk factor for unsafe driving [19e21]. Using nationally representative survey data on U.S. high school seniors, the present study aimed to (1) examine the prevalence of AmED use in relation to sociodemographic characteristics; (2) investigate associations between AmED use and academic and social factors and other substance use; and (3) test
the relation between AmED use and alcohol-related unsafe driving (i.e., tickets/warnings after drinking alcohol and accidents after drinking alcohol). Few studies have examined sociodemographic characteristics in relation to AmED use, especially among high school students, and findings tend to be mixed. AmED use may be most prevalent among males [4,5,22], although some studies show no gender differences [6,23]. White youth are often most likely to report AmED use [2,5,22,23], but other studies have shown that black youth have higher consumption rates [6,7]. Youth of higher socioeconomic status are more likely to use AmED [24], but again these findings are inconsistent [4,7]. Based on this limited evidence, for our first aim, we hypothesized that males, white students, and students with parents having higher educational attainment would be most likely to report AmED use. For our second aim, based on findings demonstrating a link between substance use and academic and social risk factors [25e28], we hypothesized that lower grade point average, public school attendance, 4-year college plans, cutting class, and spending more evenings out for fun and recreation would be associated with greater likelihood of AmED use. Furthermore, in accordance with existing research showing a relation between AmED use and other types of substance use [6,23,29], we hypothesized that AmED users would be more likely to have engaged in other types of substance use, including binge drinking, marijuana use, and illicit drug use, compared with non-users. For our third aim, we hypothesized that AmED use would be associated with greater likelihood of tickets/ warnings after drinking alcohol and motor vehicle accidents after drinking alcohol. Although no existing research has examined AmED use associated with unsafe driving among high school students, the strong link between AmED consumption and unsafe driving in young adult samples [3,5,16,17] and the more limited driving experience of high school students offers plausible information to guide our hypothesis. Methods Sample The present study included data from 12th-grade students who participated in the Monitoring the Future (MTF) study [30] in 2012 and 2013. The MTF samples used here are nationally representative of the U.S. 12th graders. Since 1975, MTF has conducted annual surveys of high school seniors through selfreport questionnaires completed at school. The focus of the MTF questionnaires is to assess the attitudes, beliefs, and behaviors of youth, pertaining particularly to substance use. MTF uses a three-stage randomized sampling procedure using geographic areas, schools in those areas, and specific classes within each school. Sampling weights correct for differential probabilities of selection, and all analyses in the present study accounted for the MTF survey’s complex, multistage sampling design. All procedures are reviewed and approved on an annual basis by the University of Michigan’s institutional review board for compliance with federal guidelines for the treatment of human subjects. A question regarding AmED use was added to MTF surveys in 2012. Thus, data analyzed in the present study included two consecutive cohorts of 12th-grade students from 2012 to 2013. Two (of six) within-classroom randomly administered questionnaire forms included questions pertaining to AmED use. In
M.E. Martz et al. / Journal of Adolescent Health 56 (2015) 557e563
our analytic sample (N ¼ 6,498; 51.2% female), the majority of students identified as white (65.9%), followed by Hispanic (12.8%) and black (8.0%); 13.2% of students were of other race/ ethnicity. The majority (75.6%) of students reported having a parent with at least some college education. Measures AmED use. Students were asked on the MTF survey [30], “During the last 12 months, on how many occasions (if any) have you had an alcoholic beverage mixed with an energy drink (such as Red Bull)?” Response options ranged from 1 ¼ none to 7 ¼ 40 or more occasions. AmED use was dichotomized into 1 ¼ any use and 0 ¼ no use. Existing survey studies have used similar measures of AmED use [3,23]. Sociodemographic characteristics. Sociodemographic characteristics included gender, race/ethnicity, and parent education (a proxy for socioeconomic status) which tend to show associations with adolescent substance use [30] and AmED use, more specifically [2,4e7,22e24]. Gender was coded as male (1) versus female (0). Race/ethnicity was coded as white (reference group), black, Hispanic, or other. The other race/ethnicity group included adolescents who identified as Asian, Native American/Native Alaskan, Native Hawaiian/Pacific Islander, or multiple races/ ethnicities. Parent education was measured by the highest level of education obtained by at least one parent, coded as some college education or more (1) or high school degree or less (0). Academic and social factors. Because we sought to examine broadly the correlates of AmED use concerning adolescent health and well-being, we considered academic and social risk factors shown to be associated with substance use in previous studies [25e28], including GPA, school type (public vs. private), 4-year college plans, cutting class, and evenings out for fun and recreation. Grades were measured by GPA in the current school year, coded as B or higher (1) or Cþ or lower (0). Type of high school was coded as public (1) versus private (0). College plans were coded as definitely planning to graduate from a 4-year college (1) versus planning on less than a 4-year college education (0). Cutting class (i.e., missing without an excuse) was coded as at least one class cut in the previous 4 weeks (1) versus no classes cut (0). Evenings out for fun and recreation during a typical week was coded as three or more evenings out (1) versus two or fewer evenings out (0). Other substance use. Existing research shows a link between AmED use and other substance use behavior [6,23,29]. Thus, in the present study, other substance use items included binge drinking, marijuana use, and other illicit drug use. Binge drinking was measured by the frequency of consuming five or more drinks in a row within the past 2 weeks, coded as any (1) or none (0). Marijuana use within the past 12 months was measured as any (1) or none (0). Any illicit drug use (other than marijuana, alcohol, or tobacco) within the past 12 months was coded as any (1) or none (0). Alcohol-related unsafe driving. The present study included two measures of alcohol-related unsafe driving available in the MTF survey [20,30]. Driving violations (i.e., speeding, running a stop light, or improper passing) were measured by frequency of tickets or warnings received within the past 12 months that occurred after drinking alcoholic beverages. Response options
559
ranged from 0 ¼ none to 4 ¼ at least four but were dichotomized for analyses as any (1) or none (0). Motor vehicle accidents were measured by frequency of accidents (i.e., collision involving property damage or personal injury) while driving a car, truck, or motorcycle within the past 12 months that occurred after drinking alcoholic beverages. Response options ranged from 0 ¼ none to 4 ¼ at least four but were dichotomized as any (1) or none (0). Results To address Aim 1, we examined the prevalence of any AmED use among the full sample. Results indicate that approximately one quarter (24.76%) of 12th-grade students reported AmED consumption at least once during the past 12 months. Although more students reported past year AmED use in 2012 than in 2013 (26.11% in 2012 and 23.27% in 2013), this difference was not significant. In terms of associations between AmED use and other substance use, 62.36% of students reported any past 12 month alcohol use and 23.72% reported any past 2 week binge drinking. Among youth who reported past 12 month AmED use, 59.33% also reported binge drinking within the past two weeks. Figure 1 shows percentages of any past year AmED use. Table 1 displays percentages of AmED use among the total sample and sociodemographic subgroups, using the full AmED item response range. Bivariate logistic regression analyses (not shown) indicate that males had significantly greater odds of any AmED use than females (odds ratio [OR] ¼ 1.37; p < .001). For race/ethnicity, white students showed significantly greater odds of AmED use than black students (OR ¼ 3.29; p < .001), Hispanic students (OR ¼ 1.33; p < .05), and students of other race/ethnicity (OR ¼ 1.28; p < .01). Hispanics (OR ¼ 2.48; p < .001) and students of other race/ethnicity (OR ¼ 2.56; p < .001) had significantly greater odds of AmED use than black students. There were no significant differences in AmED use between Hispanic students and students of other race/ethnicity. No significant differences in AmED use were found based on parent education. For Aim 2, we examined correlates of AmED use through three multivariable logistic regression models (Table 2). The first model included only sociodemographic characteristics, the second model added academic and social factors, and the third model added other substance use items. Similar to our bivariate analyses, results of Model 1 indicate that males had significantly greater odds of AmED use than females. Additionally, white students had significantly greater odds of reporting AmED use than black students, Hispanic students, and students of other race/ethnicity. We found no significant differences in AmED use by parent education. Among the items included in Model 2, low GPA, cutting class at least once during the past 4 weeks, and spending three or more evenings out for fun and recreation during the past week were each significantly associated with greater odds of AmED use. School type (public versus private) and plans to attend a 4-year college were not significantly associated with AmED use. Results of Model 3 indicate that, controlling for sociodemographic groups and academic and social factors, binge drinking, marijuana use, and other illicit drug use were each significantly associated with greater odds of AmED consumption. To address Aim 3, we examined alcohol-related unsafe driving associated with AmED use in two logistic regression models (Table 3). The first model examined AmED use in relation to tickets or warnings after alcohol use, and the second model examined AmED use associated with accidents after alcohol
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Figure 1. Percentages of sociodemographic subgroups reporting the past 12-month AmED use. Total weighted sample N ¼ 6,498; 24.76% of total sample reported any AmED use during the past year.
consumption. Both models controlled for sociodemographic groups, social and academic factors, and other substance use. Despite the fact that a relatively small number of students (N ¼ 87) reported receiving tickets or warnings after drinking alcohol, AmED use was significantly associated with greater odds of tickets or warnings after alcohol use, controlling for all other variables included in the model. This finding held even after accounting for the strong effect of binge drinking. As with driving violations, a small number (N ¼ 44) of students reported motor vehicle accidents after alcohol use. Yet, results show that AmED use was also significantly associated with greater odds of accidents after alcohol use, controlling for all other variables including binge drinking. Discussion Our findings indicate that AmED use is relatively common, with nearly one quarter of 12th-grade students reporting any
AmED consumption within the past year. Thus, high school seniors appear to be consuming AmED at rates similar to those of college students. Also in-line with previous research on college and adult-aged populations [3,5,13,16], the present study found associations between AmED use and alcohol-related unsafe driving. To our knowledge, this is the first nationally representative study to identify prevalence rates of AmED use and associations between AmED use and unsafe driving among U.S. high school students. Supporting our hypotheses for Aim 1, we found that AmED consumption was most common among males and white students, consistent with some previous research on AmED use [2,4e6,22,23] and substance use more broadly [30]. However, when including academic and social factors and substance use items in our analytic model, gender no longer remained significantly associated with AmED use. In accordance with other studies showing no significant differences by gender or race/ ethnicity, results from the present study suggest that both male
Table 1 Percentage of total sample and sociodemographic subgroups reporting the past 12-month occasions of AmED use N
Number of Occasions 0
Overall Sociodemographic groups Gender Male Female Race/ethnicity White Black Hispanic Other race Parent education Some college High school or less
1e2
3e5
6e9
10e19
20e39
40þ
%
%
%
%
%
%
%
6,498
75.24
11.74
5.31
3.24
1.97
0.88
1.63
3,169 3,329
72.23 78.07
11.95 11.54
6.09 4.56
3.83 2.69
2.73 1.24
0.89 0.87
2.26 1.02
4,283 522 836 857
72.57 89.66 77.82 77.28
12.75 5.95 10.75 11.21
6.18 2.21 4.79 3.34
3.72 0.96 2.14 3.37
2.31 0.48 1.64 1.46
0.72 0.55 1.13 1.67
1.76 0.15 1.77 1.71
4,911 1,587
74.51 77.50
12.21 10.28
5.15 5.78
3.48 2.51
2.11 1.52
0.87 0.91
1.66 1.52
AmED ¼ alcohol mixed with energy drinks.
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561
Table 2 Logistic regression models of the past 12-month AmED use
Sociodemographic groups Gendera Male Race/ethnicityb Black Hispanic Other Parent educationc Some college Academic and social factors Low GPAd Public schoole 4-year college plansf one class cutg three evenings outh Substance use Binge drinking past 2 weeks Marijuana use past 12 months Other illicit drug use past 12 months
Model 1; OR (95% CI)
Model 2; OR (95% CI)
Model 3; OR (95% CI)
1.33 (1.62e1.52)***
1.26 (1.10e1.45)**
1.04 (0.88e1.23)
0.32 (0.22e0.46)*** 0.78 (0.63e0.97)* 0.79 (0.66e0.94)**
0.31 (0.21e0.45)*** 0.71 (0.57e0.90)** 0.73 (0.61e0.89)**
0.33 (0.22e0.50)*** 0.72 (0.55e0.95)* 0.79 (0.64e0.99)*
1.09 (0.92e1.30)
1.19 (1.00e1.43)
1.11 (0.90e1.37)
1.26 1.33 0.94 2.55 1.93
(1.05e1.51)* (0.96e1.86) (0.80e1.09) (2.22e2.94)*** (1.68e2.23)***
0.86 1.24 1.01 1.43 1.24
(0.67e1.10) (0.89e1.73) (0.84e1.21) (1.20e1.71)*** (1.04e1.47)*
5.21 (4.31e6.29)*** 3.18 (2.65e3.82)*** 2.78 (2.30e3.37)***
Total weighted sample N ¼ 6,498. AmED ¼ alcohol mixed with energy drinks; CI ¼ confidence interval; GPA ¼ grade point average; OR ¼ odds ratio. a Reference category is female. b Reference category is white. c Reference category is high school or less. d Reference category is B or higher. e Reference category is private school. f Reference category is less than 4-year college plans. g Reference category is no classes cut during the past 4 weeks. h Reference category is two evenings out for fun and recreation during the past week. *p < .05; **p < .01; ***p < .001.
and female substance users may be at similar risk for AmED use after accounting for other risk factors. The physiological differences in alcohol metabolism for females compared with males, with women often becoming more intoxicated than men after consuming the same quantity of alcohol [31,32], highlights the need for future research to examine whether the effects of AmED use, and associated consequences, vary by gender. Our hypothesis that students with parents having higher educational attainment would be more likely to report AmED use was not supported. As with gender and race/ethnicity, conflicting findings in the literature indicate that additional research is needed to examine the relation between AmED consumption and parent education and other measures of socioeconomic status [4,7,24]. Results from the present study indicate that certain academic and social factors may be related to a greater likelihood of AmED use. As hypothesized, low grades were a risk factor for AmED use. However, against our hypotheses, school type (private vs. public) and 4-year college plans were not associated with AmED use. Although students attending public schools have been found to have higher rates of alcohol use than those of students at private schools [33], our findings suggest that school type may not be a factor in risk for AmED use. Considering that most studies on AmED use have used college student samples, our findings on college plans suggest that adolescents who do not attend college may be at similar risk for consuming AmED. The present study also showed an association between AmED use and cutting class and evenings out for fun and recreation, supporting our hypotheses. Given that existing research has identified cutting class and evenings out for fun and recreation as substance use risk factors [27,28], our findings suggest that placing AmED use in the greater constellation of
substance use behaviors may be appropriate when identifying emerging trends among youth. The present study supported our hypothesis, and built on previous findings, by showing an association between AmED consumption and other substance use, including binge drinking, marijuana use, and other illicit drug use [6,23,25]. Thus, including questions about AmED on substance use screening tools may be a useful strategy to help identify youth with broader substance use problems. Given that adolescent-onset substance use is linked to the development of later substance use problems [34,35], identifying AmED users during high school may target youth at risk for continued AmED consumption and associated negative consequences through early adulthood. Perhaps one of the most striking, yet troubling, findings from the present study was the association between AmED use and tickets/warnings and accidents after drinking alcohol, which was consistent with our hypothesis. Although we were unable to determine whether tickets or warnings and accidents related to drinking and driving occurred directly as a result of AmED use, by controlling for binge drinking in our analytic model, our findings suggest that youth who engage in AmED use may be especially at risk for alcohol-related unsafe driving. Motor vehicle injuries account for the greatest proportion of deaths among adolescents [18], indicating that more closely examining factors associated with alcohol-related unsafe driving among high school students is an important area of future research. Despite the importance and novelty of our findings, limitations exist. First, the data included in the present study are crosssectional. Thus, we could not assess temporal ordering of AmED use in relation to unsafe driving. Second, the survey forms offered limited item availability. Response options for AmED prevalence
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Table 3 Logistic regression models of any tickets or warnings and accidents after alcohol use during the past 12 months Tickets/warnings; OR (95% CI) Sociodemographic groups Gendera Male Race/ethnicityb Black Hispanic Other Parent educationc Some college Academic and social factors Low GPAd Public schoole 4-year college plansf one class cutg three evenings outh Substance use Binge drinking past 2 weeks Marijuana use past 12 months Other illicit drug use past 12 months AmED use AmED use past 12 months
Accidents; OR (95% CI)
1.66 (0.90e3.01)
1.32 (0.56e3.13)
0.69 (0.19e2.53) 0.47 (0.17e1.35) 1.52 (0.73e3.14)
1.06 (0.26e4.30) 0.26 (0.04e1.74) 1.42 (0.47e4.27)
0.77 (0.40e1.48)
1.19 (0.53e2.68)
0.95 1.44 0.47 1.26 1.48
2.36 0.43 0.40 1.97 0.83
(0.53e1.70) (0.44e4.67) (0.27e0.84)* (0.72e2.20) (0.80e2.72)
12.81 (3.35e48.97)** 1.44 (0.52e4.02)
(0.98e5.68) (0.14e1.35) (0.15e1.05) (0.84e4.60) (0.35e1.98)
3.85 (1.10e13.46)* 1.79 (0.43e7.51)
1.78 (0.94e3.38)
1.92 (0.77e4.78)
2.23 (1.07e4.62)*
4.32 (1.27e4.66)*
Total weighted sample N ¼ 6,498. AmED ¼ alcohol mixed with energy drinks; CI ¼ confidence interval; GPA ¼ grade point average; OR ¼ odds ratio. a Reference category is female. b Reference category is white. c Reference category is high school or less. d Reference category is B- or higher. e Reference category is private school. f Reference category is less than 4-year college plans. g Reference category is no classes cut during the past 4 weeks. h Reference category is two evenings out for fun and recreation during the past week. *p < .05; **p < .001.
included only past year rates of use. Besides the measures of unsafe driving included in the present study, no other items were available to assess alcohol-related consequences. Future studies should investigate prevalence and correlates of AmED use at different levels of intensity and frequency, as well as AmED use associated with other alcohol-related consequences. Third, there were no available measures of typical risky driving behaviors, or of driving after alcohol consumption that did not result in tickets/ warnings or accidents. Thus, the extent of unsafe driving in this sample may be underestimated. To assess the unique association between AmED use and unsafe driving, future studies are needed to control for typical risky driving behaviors and risk-seeking personality traits. Finally, our analyses were limited by the small number of students who reported alcohol-related unsafe driving. In terms of public health, such low numbers are encouraging. Despite the low incidence, we found a relatively strong association between AmED consumption and unsafe driving. In summary, AmED use has emerged as a risky drinking behavior both on the individual level and in the public health domain. Our findings provide evidence showing that AmED consumption is relatively common among high school seniors and associated with certain sociodemographic characteristics, academic and social factors, and other substance use. Additionally, an important and novel contribution of this study is the finding that AmED use is associated with a greater likelihood of
alcohol-related unsafe driving among high school students. The present study provides a needed foundation for future studies to examine more detailed measures of AmED use and to investigate more direct associations between AmED consumption and other health risk behaviors. Acknowledgments The authors thank Deborah Kloska for assistance with analyses. The research conducted in this article was funded by support from the National Institute on Drug Abuse (R01 DA001411 to L. Johnston) and the National Institute on Alcohol Abuse and Alcoholism (R21 AA021426 to M.E.P.). References [1] FDA news release. FDA warning letters issued to four makers of caffeinated alcoholic beverages. Available at: http://www.fda.gov/NewsEvents/ Newsroom/PressAnnouncements/ucm234109.htm; Nov 2010. Accessed August 19, 2014. [2] Berger L, Fendrich M, Fuhrmann D. Alcohol mixed with energy drinks: Are there associated negative consequences beyond hazardous drinking in college students? Addict Behav 2013;38:2428e32. [3] Brache K, Stockwell T. Drinking patterns and risk behaviors associated with combined alcohol and energy drink consumption in college drinkers. Addict Behav 2011;36:1133e40. [4] Miller KE. Wired: Energy drinks, jock identity, masculine norms, and risk taking. J Am Coll Health 2008;56:481e9. [5] O’Brien MC, McCoy TP, Rhodes SD, et al. Caffeinated cocktails: Energy drink consumption, high-risk drinking, and alcohol-related consequences among college students. Acad Emerg Med 2008;15:453e60. [6] Azagba S, Langille D, Asbridge M. The consumption of alcohol mixed with energy drinks: Prevalence and key correlates among Canadian high school. CMAJ Open 2013;1:19e26. [7] Kponee KZ, Siegel M, Jernigan DH. The use of caffeinated alcoholic beverages among underage drinkers: Results of a national survey. Addict Behav 2014;39:253e8. [8] Chassin L, Hussong A, Barrera M, et al. Adolescent substance use. In: Lerner RM, Steinberg L, eds. Handbook of Adolescent Psychology. 2nd edition. New York, NY: Wiley; 2004:665e96. [9] Coffman DL, Patrick ME, Palen LA, et al. Why do high school seniors drink? Implications for a targeted approach to intervention. Prev Sci 2007;8: 241e8. [10] Blankson KL, Thompson AM, Ahrendt DM, Patrick V. Energy drinks: What teenagers (and their doctors) should know. Pediatr Rev 2013;34:55e62. [11] Ferreira SE, de Mello MT, Pompéia S, de Souza-Formigoni MLO. Effects of energy drink ingestion on alcohol intoxication. Alcohol Clin Exp Res 2006; 30:598e605. [12] Marczinski CA, Fillmore MT, Bardgett ME. Effects of energy drinks mixed with alcohol on behavioral control: Risks for college students consuming trendy cocktails. Alcohol Clin Exp Res 2011;35:1282e92. [13] Arria A, O’Brien MC. The “high” risk of energy drinks. JAMA 2011;305: 600e1. [14] Patrick ME, Maggs JL. Energy drinks and alcohol: Links to alcohol behaviors and consequences across 56 days. J Adolesc Health 2014;54:454e9. [15] Mallett KA, Scaglione N, Hultgren B, Turrisi R. Are all alcohol and energy drink users the same? Examining individual variation in relation to alcohol mixed with energy drink use, risky drinking, and consequences. Psychol Addict Behav 2014;28:97e104. [16] Woolsey CL, Jacobson BH, Williams RD, et al. A comparison of the combined-use of alcohol & energy drinks to alcohol-only on high-risk drinking and driving behaviors. Subst Use Misuse 2014;50:1e7. [17] Howland J, Rohsenow DJ, Arnedt JT, et al. The acute effects of caffeinated versus non-caffeinated alcoholic beverage on driving performance and attention/reaction time. Addiction 2011;106:335e41. [18] Teen Drivers: Fact sheet. Atlanta, GA: Centers for Disease Control and Prevention. Available at: http://www.cdc.gov/MotorVehicleSafety/Teen_ Drivers/teendrivers_factsheet.html; 2012. Accessed August 19, 2014. [19] O’Malley PM, Johnston LD. Driving after drug or alcohol use by US high school seniors, 2001-2011. Am J Public Health 2013;103:2027e34. [20] Terry-McElrath YM, Malley PMO, Johnston LD. Alcohol and marijuana use patterns associated with unsafe driving among U. S. high school seniors: High use frequency, concurrent use, and simultaneous use. J Stud Alcohol Drugs 2014;75:378e89. [21] Alcohol-impaired driving. Traffic safety facts, 2010 data (DOT HS 811 606). Washington, DC: U.S. Department of Transportation; 2012.
M.E. Martz et al. / Journal of Adolescent Health 56 (2015) 557e563 [22] Velazquez CE, Poulos NS, Latimer LA, Pasch KE. Associations between energy drink consumption and alcohol use behaviors among college students. Drug Alcohol Depend 2012;123:167e72. [23] Snipes DJ, Benotsch EG. High-risk cocktails and high-risk sex: Examining the relation between alcohol mixed with energy drink consumption, sexual behavior, and drug use in college students. Addict Behav 2013;38:1418e23. [24] Berger LK, Fendrich M, Chen H, et al. Sociodemographic correlates of energy drink consumption with and without alcohol: Results of a community survey. Addict Behav 2011;36:516e9. [25] Brown SA, McGue M, Maggs J, et al. A developmental perspective on alcohol and youths 16 to 20 years of age. Pediatrics 2008;121(Suppl 4): S290e310. [26] Dodge KA, Malone PS, Lansford JE, et al. A dynamic cascade model of the development of substance use onset. Monogr Soc Res Child Dev 2009;74:1e120. [27] Patrick ME, Schulenberg JE, Martz ME, et al. Extreme binge drinking among 12th-grade students in the United States: Prevalence and predictors. JAMA Pediatr 2013;167:1019e25. [28] Patrick ME, Schulenberg JE. Alcohol use and heavy episodic drinking prevalence and predictors among national samples of American eighthand tenth grade students. J Stud Alcohol Drugs 2010;71:41e5.
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[29] Flotta D, Micò R, Nobile CGA, et al. Consumption of energy drinks, alcohol, and alcohol-mixed energy drinks among Italian adolescents. Alcohol Clin Exp Res 2014:1e8. [30] Johnston LD, O’Malley PM, Bachman JG, et al. Monitoring the Future national survey results on drug use, 1975e2013. Volume I: Secondary school students. Ann Arbor, MI: Institute for Social Research, The University of Michigan; 2013. [31] Thomasson HR. Gender differences in alcohol metabolism: Physiological responses to ethanol. In: Galanter M, ed. Recent Developments in Alcoholism. New York: Plenum; 1995:163e79. [32] Tuchman E. Women and addiction: The importance of gender issues in substance abuse research. J Addict Dis 2010;29:127e38. [33] O’Malley PM, Johnston LD, Bachman JG, et al. How substance use differs among American secondary schools. Prev Sci 2006;7:409e20. [34] Patrick ME, Schulenberg JE, O’Malley PM, et al. Age-related changes in reasons for using alcohol and marijuana from ages 18 to 30 in a national sample. Psychol Addict Behav 2011;25:330e9. [35] Zucker RA. Anticipating problem alcohol use developmentally from childhood into middle adulthood: What have we learned? Addiction 2008; 103(Suppl 1):100e8.
www.jahonline.org Original article
Alcohol Mixed With Energy Drink Use Among U.S. 12th-Grade Students: Prevalence, Correlates, and Associations With Unsafe Driving Meghan E. Martz, M.S. a, b, *, Megan E. Patrick, Ph.D. a, and John E. Schulenberg, Ph.D. a, b a b
Institute for Social Research, University of Michigan, Ann Arbor, Michigan Developmental Psychology Department, University of Michigan, Ann Arbor, Michigan
Article history: Received August 19, 2014; Accepted January 26, 2015 Keywords: Alcohol mixed with energy drinks (AmED); Alcohol; Energy drink; Drinking; High school students; Driving
A B S T R A C T
Purpose: The consumption of alcohol mixed with energy drinks (AmED) is a risky drinking behavior, most commonly studied using college samples. We know little about rates of AmED use and its associations with other risk behaviors, including unsafe driving, among high school students. This study examined the prevalence and correlates of AmED use among high school seniors in the United States. Methods: Nationally representative analytic samples included 6,498 12th-grade students who completed Monitoring the Future surveys in 2012 and 2013. Focal measures included AmED use, sociodemographic characteristics, academic and social factors, other substance use, and unsafe driving (i.e., tickets/warnings and accidents) after alcohol consumption. Results: Approximately one in four students (24.8%) reported AmED use during the past 12 months. Rates of AmED use were highest among males and white students. Using multivariable logistic regression models controlling for sociodemographic characteristics, results indicate that students who cut class, spent more evenings out for fun and recreation, and reported binge drinking, marijuana use, and illicit drug use had a greater likelihood of AmED use. AmED use was also associated with greater odds of alcohol-related unsafe driving, even after controlling for sociodemographic, academic, and social factors and other substance use. Conclusions: AmED use among 12th-grade students is common and associated with certain sociodemographic, academic, social, and substance use factors. AmED use is also related to alcoholrelated unsafe driving, which is a serious public health concern. Ó 2015 Society for Adolescent Health and Medicine. All rights reserved.
Conflicts of Interest: The authors report no potential, perceived, or real conflicts of interest. Disclaimer: The content here is solely the responsibility of the authors and does not necessarily represent the official views of the sponsors. The study sponsor had no role in (1) study design; (2) the collection, analysis, and interpretation of data; (3) the writing of the report; or (4) the decision to submit the article for publication. * Address correspondence to: Meghan E. Martz, M.S., University of Michigan Developmental Psychology Department, University of Michigan, 2044 East Hall, 530 Church Street, Ann Arbor, MI 48109. E-mail address: [email protected] (M.E. Martz). 1054-139X/Ó 2015 Society for Adolescent Health and Medicine. All rights reserved. http://dx.doi.org/10.1016/j.jadohealth.2015.01.019
IMPLICATIONS AND CONTRIBUTION
Research on alcohol mixed with energy drink use has focused predominantly on college students. The present study, using nationally representative samples of high school seniors, shows that this potentially dangerous drinking behavior occurs earlier during high school and is associated with other risky behaviors, including alcohol-related unsafe driving.
The use of alcohol mixed with energy drinks (AmED) has emerged as a high-risk drinking behavior, especially among youth. Although the U.S. Food and Drug Administration banned the sale of premixed alcoholic energy drinks in 2010 after deeming caffeine an “unsafe food additive” for alcoholic beverages [1], AmED use is relatively common. Most studies examining AmED consumption have predominately used college samples, finding prevalence rates ranging from 20%e25% [2e5]. In one of the few studies using a high school student sample, Azagba et al. [6] found that more than one third of Canadian high school seniors reported AmED use within the past year. In
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another study using a panel sample of youth drinkers, 7.4% of 16- to 18-year-olds reported AmED use within the past 30 days [7]. High schooleaged youth appear to be engaging in AmED use; yet, nationally representative prevalence rates and correlates among youth in the United States remain unknown. This is troublesome, considering that adolescents are especially vulnerable to risky drinking behaviors [8,9]. A serious danger of AmED use is that the stimulant effects of caffeine may be perceived as offsetting the depressant effects of alcohol, resulting in individuals feeling less intoxicated than they actually are [10e12]. Researchers have described this as “wide awake drunkenness” [13]. Thus, energy drinks may be used with the intent to diminish the depressant effects of alcohol. For example, college students’ motivations for AmED use include being able to drink more, getting drunk faster, and feeling less tired when drinking [12]. Not only does the discrepancy between perceived and actual intoxication contribute to drinking past the point of intoxication, but also it is associated with increased risktaking behavior [2,7,11,14]. College students classified as moderate drinkers with a high proportion of drinking occasions involving AmED use reported more physical consequences, including hangovers, blackouts, and vomiting compared with moderate drinkers with low AmED use [15]. Likewise, in a study that investigated consequences of AmED use through daily surveys of college students, students experienced more negative consequences and reported drinking greater amounts of alcohol on days when they consumed alcohol and energy drinks, compared with days when they consumed only alcohol [14]. AmED use is also associated with impaired driving, although this research is again limited to college students and adult samples [3,5,16,17]. Consuming AmED may contribute to driving after drinking because of the subjective perception that caffeine offsets the effects of alcohol that impair coordination and attention. College students who engaged in more frequent AmED use have been found to report significantly greater odds of driving after drinking, even after controlling for age, gender, binge drinking, and risk-taking propensity [3]. In a study testing subjective versus objective measures of alcohol intoxication, young adults reported feeling that they had less impaired motor coordination when they consumed AmED compared with when they consumed only alcohol [11]. Despite subjects’ perceptions of reduced effects of intoxication, AmED use did not improve objective measures of motor coordination or visual reaction time. Additionally, breath alcohol concentration remained unaffected by AmED use. In fact, in a study that tested driving performance using a driving simulator task, AmED use was associated with a greater number of speed fluctuations, lateral movements, and increased crashes compared with consuming alcohol without the addition of energy drinks [17]. To our knowledge, no studies to date have investigated the association between AmED use and unsafe driving among high school students. Research is needed to test this association for three key reasons. First, high school students are likely less experienced drivers. Second, the risk of motor vehicle crashes in the United States is highest among adolescents aged 16e19 years compared with any other age group [18]. Third, substance use is a known risk factor for unsafe driving [19e21]. Using nationally representative survey data on U.S. high school seniors, the present study aimed to (1) examine the prevalence of AmED use in relation to sociodemographic characteristics; (2) investigate associations between AmED use and academic and social factors and other substance use; and (3) test
the relation between AmED use and alcohol-related unsafe driving (i.e., tickets/warnings after drinking alcohol and accidents after drinking alcohol). Few studies have examined sociodemographic characteristics in relation to AmED use, especially among high school students, and findings tend to be mixed. AmED use may be most prevalent among males [4,5,22], although some studies show no gender differences [6,23]. White youth are often most likely to report AmED use [2,5,22,23], but other studies have shown that black youth have higher consumption rates [6,7]. Youth of higher socioeconomic status are more likely to use AmED [24], but again these findings are inconsistent [4,7]. Based on this limited evidence, for our first aim, we hypothesized that males, white students, and students with parents having higher educational attainment would be most likely to report AmED use. For our second aim, based on findings demonstrating a link between substance use and academic and social risk factors [25e28], we hypothesized that lower grade point average, public school attendance, 4-year college plans, cutting class, and spending more evenings out for fun and recreation would be associated with greater likelihood of AmED use. Furthermore, in accordance with existing research showing a relation between AmED use and other types of substance use [6,23,29], we hypothesized that AmED users would be more likely to have engaged in other types of substance use, including binge drinking, marijuana use, and illicit drug use, compared with non-users. For our third aim, we hypothesized that AmED use would be associated with greater likelihood of tickets/ warnings after drinking alcohol and motor vehicle accidents after drinking alcohol. Although no existing research has examined AmED use associated with unsafe driving among high school students, the strong link between AmED consumption and unsafe driving in young adult samples [3,5,16,17] and the more limited driving experience of high school students offers plausible information to guide our hypothesis. Methods Sample The present study included data from 12th-grade students who participated in the Monitoring the Future (MTF) study [30] in 2012 and 2013. The MTF samples used here are nationally representative of the U.S. 12th graders. Since 1975, MTF has conducted annual surveys of high school seniors through selfreport questionnaires completed at school. The focus of the MTF questionnaires is to assess the attitudes, beliefs, and behaviors of youth, pertaining particularly to substance use. MTF uses a three-stage randomized sampling procedure using geographic areas, schools in those areas, and specific classes within each school. Sampling weights correct for differential probabilities of selection, and all analyses in the present study accounted for the MTF survey’s complex, multistage sampling design. All procedures are reviewed and approved on an annual basis by the University of Michigan’s institutional review board for compliance with federal guidelines for the treatment of human subjects. A question regarding AmED use was added to MTF surveys in 2012. Thus, data analyzed in the present study included two consecutive cohorts of 12th-grade students from 2012 to 2013. Two (of six) within-classroom randomly administered questionnaire forms included questions pertaining to AmED use. In
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our analytic sample (N ¼ 6,498; 51.2% female), the majority of students identified as white (65.9%), followed by Hispanic (12.8%) and black (8.0%); 13.2% of students were of other race/ ethnicity. The majority (75.6%) of students reported having a parent with at least some college education. Measures AmED use. Students were asked on the MTF survey [30], “During the last 12 months, on how many occasions (if any) have you had an alcoholic beverage mixed with an energy drink (such as Red Bull)?” Response options ranged from 1 ¼ none to 7 ¼ 40 or more occasions. AmED use was dichotomized into 1 ¼ any use and 0 ¼ no use. Existing survey studies have used similar measures of AmED use [3,23]. Sociodemographic characteristics. Sociodemographic characteristics included gender, race/ethnicity, and parent education (a proxy for socioeconomic status) which tend to show associations with adolescent substance use [30] and AmED use, more specifically [2,4e7,22e24]. Gender was coded as male (1) versus female (0). Race/ethnicity was coded as white (reference group), black, Hispanic, or other. The other race/ethnicity group included adolescents who identified as Asian, Native American/Native Alaskan, Native Hawaiian/Pacific Islander, or multiple races/ ethnicities. Parent education was measured by the highest level of education obtained by at least one parent, coded as some college education or more (1) or high school degree or less (0). Academic and social factors. Because we sought to examine broadly the correlates of AmED use concerning adolescent health and well-being, we considered academic and social risk factors shown to be associated with substance use in previous studies [25e28], including GPA, school type (public vs. private), 4-year college plans, cutting class, and evenings out for fun and recreation. Grades were measured by GPA in the current school year, coded as B or higher (1) or Cþ or lower (0). Type of high school was coded as public (1) versus private (0). College plans were coded as definitely planning to graduate from a 4-year college (1) versus planning on less than a 4-year college education (0). Cutting class (i.e., missing without an excuse) was coded as at least one class cut in the previous 4 weeks (1) versus no classes cut (0). Evenings out for fun and recreation during a typical week was coded as three or more evenings out (1) versus two or fewer evenings out (0). Other substance use. Existing research shows a link between AmED use and other substance use behavior [6,23,29]. Thus, in the present study, other substance use items included binge drinking, marijuana use, and other illicit drug use. Binge drinking was measured by the frequency of consuming five or more drinks in a row within the past 2 weeks, coded as any (1) or none (0). Marijuana use within the past 12 months was measured as any (1) or none (0). Any illicit drug use (other than marijuana, alcohol, or tobacco) within the past 12 months was coded as any (1) or none (0). Alcohol-related unsafe driving. The present study included two measures of alcohol-related unsafe driving available in the MTF survey [20,30]. Driving violations (i.e., speeding, running a stop light, or improper passing) were measured by frequency of tickets or warnings received within the past 12 months that occurred after drinking alcoholic beverages. Response options
559
ranged from 0 ¼ none to 4 ¼ at least four but were dichotomized for analyses as any (1) or none (0). Motor vehicle accidents were measured by frequency of accidents (i.e., collision involving property damage or personal injury) while driving a car, truck, or motorcycle within the past 12 months that occurred after drinking alcoholic beverages. Response options ranged from 0 ¼ none to 4 ¼ at least four but were dichotomized as any (1) or none (0). Results To address Aim 1, we examined the prevalence of any AmED use among the full sample. Results indicate that approximately one quarter (24.76%) of 12th-grade students reported AmED consumption at least once during the past 12 months. Although more students reported past year AmED use in 2012 than in 2013 (26.11% in 2012 and 23.27% in 2013), this difference was not significant. In terms of associations between AmED use and other substance use, 62.36% of students reported any past 12 month alcohol use and 23.72% reported any past 2 week binge drinking. Among youth who reported past 12 month AmED use, 59.33% also reported binge drinking within the past two weeks. Figure 1 shows percentages of any past year AmED use. Table 1 displays percentages of AmED use among the total sample and sociodemographic subgroups, using the full AmED item response range. Bivariate logistic regression analyses (not shown) indicate that males had significantly greater odds of any AmED use than females (odds ratio [OR] ¼ 1.37; p < .001). For race/ethnicity, white students showed significantly greater odds of AmED use than black students (OR ¼ 3.29; p < .001), Hispanic students (OR ¼ 1.33; p < .05), and students of other race/ethnicity (OR ¼ 1.28; p < .01). Hispanics (OR ¼ 2.48; p < .001) and students of other race/ethnicity (OR ¼ 2.56; p < .001) had significantly greater odds of AmED use than black students. There were no significant differences in AmED use between Hispanic students and students of other race/ethnicity. No significant differences in AmED use were found based on parent education. For Aim 2, we examined correlates of AmED use through three multivariable logistic regression models (Table 2). The first model included only sociodemographic characteristics, the second model added academic and social factors, and the third model added other substance use items. Similar to our bivariate analyses, results of Model 1 indicate that males had significantly greater odds of AmED use than females. Additionally, white students had significantly greater odds of reporting AmED use than black students, Hispanic students, and students of other race/ethnicity. We found no significant differences in AmED use by parent education. Among the items included in Model 2, low GPA, cutting class at least once during the past 4 weeks, and spending three or more evenings out for fun and recreation during the past week were each significantly associated with greater odds of AmED use. School type (public versus private) and plans to attend a 4-year college were not significantly associated with AmED use. Results of Model 3 indicate that, controlling for sociodemographic groups and academic and social factors, binge drinking, marijuana use, and other illicit drug use were each significantly associated with greater odds of AmED consumption. To address Aim 3, we examined alcohol-related unsafe driving associated with AmED use in two logistic regression models (Table 3). The first model examined AmED use in relation to tickets or warnings after alcohol use, and the second model examined AmED use associated with accidents after alcohol
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Figure 1. Percentages of sociodemographic subgroups reporting the past 12-month AmED use. Total weighted sample N ¼ 6,498; 24.76% of total sample reported any AmED use during the past year.
consumption. Both models controlled for sociodemographic groups, social and academic factors, and other substance use. Despite the fact that a relatively small number of students (N ¼ 87) reported receiving tickets or warnings after drinking alcohol, AmED use was significantly associated with greater odds of tickets or warnings after alcohol use, controlling for all other variables included in the model. This finding held even after accounting for the strong effect of binge drinking. As with driving violations, a small number (N ¼ 44) of students reported motor vehicle accidents after alcohol use. Yet, results show that AmED use was also significantly associated with greater odds of accidents after alcohol use, controlling for all other variables including binge drinking. Discussion Our findings indicate that AmED use is relatively common, with nearly one quarter of 12th-grade students reporting any
AmED consumption within the past year. Thus, high school seniors appear to be consuming AmED at rates similar to those of college students. Also in-line with previous research on college and adult-aged populations [3,5,13,16], the present study found associations between AmED use and alcohol-related unsafe driving. To our knowledge, this is the first nationally representative study to identify prevalence rates of AmED use and associations between AmED use and unsafe driving among U.S. high school students. Supporting our hypotheses for Aim 1, we found that AmED consumption was most common among males and white students, consistent with some previous research on AmED use [2,4e6,22,23] and substance use more broadly [30]. However, when including academic and social factors and substance use items in our analytic model, gender no longer remained significantly associated with AmED use. In accordance with other studies showing no significant differences by gender or race/ ethnicity, results from the present study suggest that both male
Table 1 Percentage of total sample and sociodemographic subgroups reporting the past 12-month occasions of AmED use N
Number of Occasions 0
Overall Sociodemographic groups Gender Male Female Race/ethnicity White Black Hispanic Other race Parent education Some college High school or less
1e2
3e5
6e9
10e19
20e39
40þ
%
%
%
%
%
%
%
6,498
75.24
11.74
5.31
3.24
1.97
0.88
1.63
3,169 3,329
72.23 78.07
11.95 11.54
6.09 4.56
3.83 2.69
2.73 1.24
0.89 0.87
2.26 1.02
4,283 522 836 857
72.57 89.66 77.82 77.28
12.75 5.95 10.75 11.21
6.18 2.21 4.79 3.34
3.72 0.96 2.14 3.37
2.31 0.48 1.64 1.46
0.72 0.55 1.13 1.67
1.76 0.15 1.77 1.71
4,911 1,587
74.51 77.50
12.21 10.28
5.15 5.78
3.48 2.51
2.11 1.52
0.87 0.91
1.66 1.52
AmED ¼ alcohol mixed with energy drinks.
M.E. Martz et al. / Journal of Adolescent Health 56 (2015) 557e563
561
Table 2 Logistic regression models of the past 12-month AmED use
Sociodemographic groups Gendera Male Race/ethnicityb Black Hispanic Other Parent educationc Some college Academic and social factors Low GPAd Public schoole 4-year college plansf one class cutg three evenings outh Substance use Binge drinking past 2 weeks Marijuana use past 12 months Other illicit drug use past 12 months
Model 1; OR (95% CI)
Model 2; OR (95% CI)
Model 3; OR (95% CI)
1.33 (1.62e1.52)***
1.26 (1.10e1.45)**
1.04 (0.88e1.23)
0.32 (0.22e0.46)*** 0.78 (0.63e0.97)* 0.79 (0.66e0.94)**
0.31 (0.21e0.45)*** 0.71 (0.57e0.90)** 0.73 (0.61e0.89)**
0.33 (0.22e0.50)*** 0.72 (0.55e0.95)* 0.79 (0.64e0.99)*
1.09 (0.92e1.30)
1.19 (1.00e1.43)
1.11 (0.90e1.37)
1.26 1.33 0.94 2.55 1.93
(1.05e1.51)* (0.96e1.86) (0.80e1.09) (2.22e2.94)*** (1.68e2.23)***
0.86 1.24 1.01 1.43 1.24
(0.67e1.10) (0.89e1.73) (0.84e1.21) (1.20e1.71)*** (1.04e1.47)*
5.21 (4.31e6.29)*** 3.18 (2.65e3.82)*** 2.78 (2.30e3.37)***
Total weighted sample N ¼ 6,498. AmED ¼ alcohol mixed with energy drinks; CI ¼ confidence interval; GPA ¼ grade point average; OR ¼ odds ratio. a Reference category is female. b Reference category is white. c Reference category is high school or less. d Reference category is B or higher. e Reference category is private school. f Reference category is less than 4-year college plans. g Reference category is no classes cut during the past 4 weeks. h Reference category is two evenings out for fun and recreation during the past week. *p < .05; **p < .01; ***p < .001.
and female substance users may be at similar risk for AmED use after accounting for other risk factors. The physiological differences in alcohol metabolism for females compared with males, with women often becoming more intoxicated than men after consuming the same quantity of alcohol [31,32], highlights the need for future research to examine whether the effects of AmED use, and associated consequences, vary by gender. Our hypothesis that students with parents having higher educational attainment would be more likely to report AmED use was not supported. As with gender and race/ethnicity, conflicting findings in the literature indicate that additional research is needed to examine the relation between AmED consumption and parent education and other measures of socioeconomic status [4,7,24]. Results from the present study indicate that certain academic and social factors may be related to a greater likelihood of AmED use. As hypothesized, low grades were a risk factor for AmED use. However, against our hypotheses, school type (private vs. public) and 4-year college plans were not associated with AmED use. Although students attending public schools have been found to have higher rates of alcohol use than those of students at private schools [33], our findings suggest that school type may not be a factor in risk for AmED use. Considering that most studies on AmED use have used college student samples, our findings on college plans suggest that adolescents who do not attend college may be at similar risk for consuming AmED. The present study also showed an association between AmED use and cutting class and evenings out for fun and recreation, supporting our hypotheses. Given that existing research has identified cutting class and evenings out for fun and recreation as substance use risk factors [27,28], our findings suggest that placing AmED use in the greater constellation of
substance use behaviors may be appropriate when identifying emerging trends among youth. The present study supported our hypothesis, and built on previous findings, by showing an association between AmED consumption and other substance use, including binge drinking, marijuana use, and other illicit drug use [6,23,25]. Thus, including questions about AmED on substance use screening tools may be a useful strategy to help identify youth with broader substance use problems. Given that adolescent-onset substance use is linked to the development of later substance use problems [34,35], identifying AmED users during high school may target youth at risk for continued AmED consumption and associated negative consequences through early adulthood. Perhaps one of the most striking, yet troubling, findings from the present study was the association between AmED use and tickets/warnings and accidents after drinking alcohol, which was consistent with our hypothesis. Although we were unable to determine whether tickets or warnings and accidents related to drinking and driving occurred directly as a result of AmED use, by controlling for binge drinking in our analytic model, our findings suggest that youth who engage in AmED use may be especially at risk for alcohol-related unsafe driving. Motor vehicle injuries account for the greatest proportion of deaths among adolescents [18], indicating that more closely examining factors associated with alcohol-related unsafe driving among high school students is an important area of future research. Despite the importance and novelty of our findings, limitations exist. First, the data included in the present study are crosssectional. Thus, we could not assess temporal ordering of AmED use in relation to unsafe driving. Second, the survey forms offered limited item availability. Response options for AmED prevalence
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Table 3 Logistic regression models of any tickets or warnings and accidents after alcohol use during the past 12 months Tickets/warnings; OR (95% CI) Sociodemographic groups Gendera Male Race/ethnicityb Black Hispanic Other Parent educationc Some college Academic and social factors Low GPAd Public schoole 4-year college plansf one class cutg three evenings outh Substance use Binge drinking past 2 weeks Marijuana use past 12 months Other illicit drug use past 12 months AmED use AmED use past 12 months
Accidents; OR (95% CI)
1.66 (0.90e3.01)
1.32 (0.56e3.13)
0.69 (0.19e2.53) 0.47 (0.17e1.35) 1.52 (0.73e3.14)
1.06 (0.26e4.30) 0.26 (0.04e1.74) 1.42 (0.47e4.27)
0.77 (0.40e1.48)
1.19 (0.53e2.68)
0.95 1.44 0.47 1.26 1.48
2.36 0.43 0.40 1.97 0.83
(0.53e1.70) (0.44e4.67) (0.27e0.84)* (0.72e2.20) (0.80e2.72)
12.81 (3.35e48.97)** 1.44 (0.52e4.02)
(0.98e5.68) (0.14e1.35) (0.15e1.05) (0.84e4.60) (0.35e1.98)
3.85 (1.10e13.46)* 1.79 (0.43e7.51)
1.78 (0.94e3.38)
1.92 (0.77e4.78)
2.23 (1.07e4.62)*
4.32 (1.27e4.66)*
Total weighted sample N ¼ 6,498. AmED ¼ alcohol mixed with energy drinks; CI ¼ confidence interval; GPA ¼ grade point average; OR ¼ odds ratio. a Reference category is female. b Reference category is white. c Reference category is high school or less. d Reference category is B- or higher. e Reference category is private school. f Reference category is less than 4-year college plans. g Reference category is no classes cut during the past 4 weeks. h Reference category is two evenings out for fun and recreation during the past week. *p < .05; **p < .001.
included only past year rates of use. Besides the measures of unsafe driving included in the present study, no other items were available to assess alcohol-related consequences. Future studies should investigate prevalence and correlates of AmED use at different levels of intensity and frequency, as well as AmED use associated with other alcohol-related consequences. Third, there were no available measures of typical risky driving behaviors, or of driving after alcohol consumption that did not result in tickets/ warnings or accidents. Thus, the extent of unsafe driving in this sample may be underestimated. To assess the unique association between AmED use and unsafe driving, future studies are needed to control for typical risky driving behaviors and risk-seeking personality traits. Finally, our analyses were limited by the small number of students who reported alcohol-related unsafe driving. In terms of public health, such low numbers are encouraging. Despite the low incidence, we found a relatively strong association between AmED consumption and unsafe driving. In summary, AmED use has emerged as a risky drinking behavior both on the individual level and in the public health domain. Our findings provide evidence showing that AmED consumption is relatively common among high school seniors and associated with certain sociodemographic characteristics, academic and social factors, and other substance use. Additionally, an important and novel contribution of this study is the finding that AmED use is associated with a greater likelihood of
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