The role of caffeine in the alcohol consumption behaviors of college students

Alcohol Mixed with Energy Drinks (AmED) Use among University Students: A Systematic Review and Meta-Analysis

In the last decades, there has been a huge increase in the consumption of both Energy Drinks (EDs) and alcohol and, concurrently, these two trends generated the additional practice of mixing ED with alcohol, known as Alcohol mixed with Energy Drink (AmED). One of the most important group of AmED consumers is represented by young. Indeed, the study population of the researches in this field are mainly represented by college students and the results evidence a great range of negative consequences for health. The purpose of the systematic review was to explore the prevalence of AmED consumption among undergraduate students, together with motivations to their use, adverse effects and health-related behaviors associated to AmEDs use. The review was conducted according to the PRISMA Statement and PubMed, Scopus and Web of Science were interrogated. 42 articles, published from 2008 to 2021, were included in the review. An overall prevalence rate of 37% was estimated for AmEDs use in undergraduates, with geographical differences. Although a decrease in consumption was observed throughout the studied period, a continuous monitoring on this phenomenon is needed for identifying those risk groups that could develop risky behaviors related to AmEDs consumption and provide them targeted educational interventions.

Caffeine consumption and onset of alcohol use among early adolescents

Preventing or delaying the onset of alcohol use among children and youth is an important public health goal. One possible factor in alcohol use onset among early adolescents is caffeine. The aim of this study was to assess the possible contribution of caffeine to the onset of alcohol use during early adolescence. We used data from the Young Mountaineer Health Study Cohort. Survey data were collected from 1349 (response rate: 80.7%) 6th grade students (mean age at baseline 11.5 years) in 20 middle schools in West Virginia during the fall of 2020, and again approximately 6 months later in spring of 2021. We limited our analyses to students reporting never having used any form of alcohol at baseline. Logistic regression was employed in multivariable analyses and both Odds Ratios and Relative Risks reported. At follow-up, almost 14% of participants reported having consumed alcohol at least once and 57% used caffeine of 100 mg + daily. In multivariable analyses we controlled for social and behavioral variables known to impact tobacco use. Caffeine use was operationalized as a three-level factor: no use, <100 mg per day, and 100 + mg per day, with the latter being the approximate equivalent of the minimum of a typical cup of coffee or can of energy drink. Caffeine use of 100 mg + per day was significantly related to alcohol use at 6-months follow-up (OR: 1.79, RR: 1.56, p = .037). We conclude that caffeine consumption among 11-12-year-old adolescents may be a factor in early onset of alcohol use.

An on-premise study to investigate the effects of mixing alcohol with caffeinated beverages

OBJECTIVE

The purpose of this on-premise study was to determine if mixing alcohol with caffeinated mixers had an impact on objective and subjective intoxication.

METHODS

The study was conducted across eight drinking occasions in the City of Bristol, UK. Participants (N = 1041) were recruited outside popular night-time entertainment venues and interviewed regarding their alcohol consumption for that particular evening, including whether or not they had consumed caffeinated beverages with alcohol. Subjective intoxication was rated on an 11-point scale and objective intoxication determined with a breath alcohol test. Depending on their consumption on the night of the interview, participants also reported whether they consumed alcohol mixed with caffeinated mixers or alcohol-only on other consumption occasions.

RESULTS

Between-subjects analyses found that alcohol-caffeine consumers consumed more alcohol and had higher objective and subjective intoxication than those who consumed alcohol-only. These results remained significant regardless of whether or not they mixed alcohol with caffeinated mixers or consumed alcohol-only on the night of the interview. Within-subject analyses revealed that alcohol-caffeine consumers drank the same or less alcohol on alcohol-caffeine occasions compared to alcohol-only occasions.

CONCLUSIONS

These findings provide support that alcohol-caffeine use does not increase overall alcohol consumption, and may be one manifestation of a high risk-taking personality.

Alcohol Mixed with Energy Drinks (AmED) and Negative Alcohol-Related Consequences among South Korean College Students

Consumption of alcohol mixed with energy drinks (AmED) has been associated with various alcohol-related consequences among college students. However, more information is required to assess how this relationship is affected by sociodemographic and environmental factors. This paper investigates the association between AmED consumption and negative alcohol-related consequences while (1) stratifying AmED users by sex, (2) examining a range of outcomes specific to the college context (e.g., missing class), and (3) controlling for drinking frequency and amount. We surveyed and analyzed the data of 4592 students in a nationally representative sample of 82 colleges in South Korea. Multiple linear regression analysis was used to identify the association between AmED use and a number of alcohol-related consequences (ranging from a score of 0–12) while adjusting for covariates, including drinking frequency and intake per drinking session. Of our study population, 22.0% of alcohol-consuming men and 13.4% of alcohol-consuming women reported AmED consumption in the past 12 months. AmED users experienced a greater number of alcohol-related consequences (e.g., missing class, engaging in unplanned sexual activity) than non-AmED users (men β: 0.804, p ≤ 0.0001; women β: 0.522, p ≤ 0.0001). Male AmED users consuming alcohol once a month (β: 1.155, p ≤ 0.0001) and female users consuming less than once a month (β: 1.019, p ≤ 0.0001) experienced the greatest number of consequences compared to non-users, as did AmED users consuming 3–4 drinks per drinking session (men β: 1.012, p ≤ 0.0001; women β: 0.993, p ≤ 0.0001). Our findings reveal that both male and female college students who consume AmED experience a greater number of negative alcohol-related consequences than those who do not. Rather than high-risk drinkers, moderate drinkers who consume alcohol infrequently and/or in low amounts may experience more consequences when consumers of AmED.

Risky Alcohol Consumption and Online Activity Levels

University students engage in risky patterns of alcohol consumption, which may affect their health and performance at university. This study provides a novel analysis which tracked students' interaction with online course materials over time, and examined associations between online activity and alcohol related harm (as indicated by the Alcohol Use Disorders Identification Test). Study 1 tracked 63 undergraduate psychology students in the second half of a semester and found risky drinking behaviors were marginally related to reductions in online study activity. Study 2 tracked 88 undergraduate psychology students in the first half of a semester. Risky drinking behaviors were associated with less online activity after midday. Students reporting more alcohol related harm were less likely to login between 7 pm and midnight, and between 1 am and 6 am. This study demonstrates a potential sensitivity of online activity levels to alcohol use.

Extra-endothelial TRPV1 channels participate in alcohol and caffeine actions on cerebral artery diameter

Alcohol (ethyl alcohol; ethanol) and caffeine are the two most widely used psychoactive substances in the world. Caffeine and ethanol have both been reported to constrict cerebral arteries in several species, including humans. We have recently shown that application of 10-μM caffeine mixed with 50 mM ethanol to in vitro pressurized cerebral arteries of rats reduced ethanol-induced constriction. This effect was dependent on the presence of nitric oxide (NO^•) and could be observed in de-endothelialized arteries supplied with the NO donor sodium nitroprusside (SNP). The molecular target(s) of ethanol-caffeine interaction in cerebral arteries has remained unknown. In the present work, we used rat and mouse middle cerebral arteries (MCA) to identify the extra-endothelial effectors of NO-mediated, caffeine-induced protection against ethanol-evoked arterial constriction. Constriction of intact MCA of rat by either 50 mM ethanol or 10 μM caffeine was ablated in the presence of a selective TRPV1 pharmacological blocker. TRPV1 pharmacological block, but not block of TRPA1, PKG, or BK channels, removed caffeine-induced protection against ethanol-evoked rat MCA constriction, whether evaluated in arteries with intact endothelium or in SNP-supplemented, de-endothelialized arteries. In mouse arteries, caffeine-induced protection against ethanol-induced MCA constriction was significantly amplified, resulting in actual vasodilation, upon pharmacological block of TRPV1, and in TRPV1 knock-out arteries. Despite some species-specific differences, our study unequivocally demonstrates the presence of functional, extra-endothelial TRPV1 that participates in both endothelium-independent MCA constriction by separate exposure to ethanol or caffeine and caffeine-induced protection against ethanol-evoked MCA constriction.

Alcohol mixed with energy drink (AMED): A critical review and meta-analysis

The purpose of this systematic review and meta-analysis was to critically review the (1) prevalence of alcohol mixed with energy drink (AMED) consumption, (2) motives for AMED consumption, (3) correlates of AMED consumption, and (4) whether AMED consumption has an impact on (a) alcohol consumption, (b) subjective intoxication, and (c) risk-taking behavior. Overall a minority of the population consumes AMED, typically infrequently. Motives for AMED consumption are predominantly hedonistic and social. Meta-analyses revealed that AMED consumers drink significantly more alcohol than alcohol-only (AO) consumers. Within-subject comparisons restricted to AMED consumers revealed that alcohol consumption does not significantly differ between typical AMED and AO occasions. On past month heaviest drinking occasions, AMED users consume significantly less alcohol on AMED occasions when compared to AO occasions. AMED consumers experience significantly fewer negative consequences and risk-taking behavior on AMED occasions compared with AO occasions. Meta-analyses of subjective intoxication studies suggest that AMED consumption does not differentially affect subjective intoxication when compared to AO consumption. In conclusion, when compared to AO consumption, mixing alcohol with energy drink does not affect subjective intoxication and seems unlikely to increase total alcohol consumption, associated risk-taking behavior, nor other negative alcohol-related consequences. Further research may be necessary to fully reveal the effects of AMED.

Are energy drinks unique mixers in terms of their effects on alcohol consumption and negative alcohol-related consequences?

Introduction

Previous research has suggested that consuming alcohol mixed with energy drinks (AMED) increases overall alcohol consumption. However, there is limited research examining whether energy drinks are unique in their effects when mixed with alcohol, when compared with alcohol mixed with other caffeinated mixers (AOCM). Therefore, the aim of this survey was to investigate alcohol consumption on AMED occasions, to that on other occasions when the same individuals consumed AOCM or alcohol only (AO).

Methods

A UK-wide online student survey collected data on the frequency of alcohol consumption and quantity consumed, as well as the number of negative alcohol-related consequences reported on AO, AMED and AOCM occasions (N=250).

Results

Within-subjects analysis revealed that there were no significant differences in the number of alcoholic drinks consumed on a standard and a heavy drinking session between AMED and AOCM drinking occasions. However, the number of standard mixers typically consumed was significantly lower on AMED occasions compared with AOCM occasions. In addition, when consuming AMED, students reported significantly fewer days consuming 5 or more alcohol drinks, fewer days mixing drinks, and fewer days being drunk, compared with when consuming AOCM. There were no significant differences in the number of reported negative alcohol-related consequences on AMED occasions to AOCM occasions. Of importance, alcohol consumption and negative alcohol-related consequences were significantly less on both AMED and AOCM occasions compared with AO occasions.

Conclusion

The findings that heavy alcohol consumption occurs significantly less often on AMED occasions compared with AOCM occasions is in opposition to some earlier claims implying that greatest alcohol consumption occurs with AMED. The overall greatest alcohol consumption and associated negative consequences were clearly associated with AO occasions. Negative consequences for AMED and AOCM drinking occasions were similar, suggesting that energy drink was comparable with AOCM in this regard.

Energy Drinks and Binge Drinking Predict College Students' Sleep Quantity, Quality, and Tiredness

This study examines whether energy drink use and binge drinking predict sleep quantity, sleep quality, and next-day tiredness among college students. Web-based daily data on substance use and sleep were collected across four semesters in 2009 and 2010 from 667 individuals for up to 56 days each, yielding information on 25,616 person-days. Controlling for average levels of energy drink use and binge drinking (i.e., 4+ drinks for women, 5+ drinks for men), on days when students consumed energy drinks, they reported lower sleep quantity and quality that night, and greater next-day tiredness, compared to days they did not use energy drinks. Similarly, on days when students binge drank, they reported lower sleep quantity and quality that night, and greater next-day tiredness, compared to days they did not binge drink. There was no significant interaction effect between binge drinking and energy drink use on the outcomes.

A Survey of Energy Drink Consumption Patterns Among College Students at a Mostly Hispanic University

Background: The purpose of this study was to determine energy drink (ED) consumption patterns among Hispanic college students. We measured the prevalence and frequency of ED consumption according to gender, degree programs, and specific university-related and social situations. In addition, we assessed the frequency of consumption of EDs mixed with alcoholic beverages. Methods: A total of 508 college students from the University of Puerto Rico, the largest Hispanic institution of higher education statewide, completed an online questionnaire. Results: Twenty-one percent of participants reported consuming EDs with the majority consuming EDs either occasionally (every 2-3 months) or at least once or twice a month. Men were found to be more likely to consume EDs than women. Undergraduate students were found less likely to consume EDs than graduate students. Most students consumed EDs while studying and during social activities. More than one-third of participants that consume EDs admitted mixing them with an alcoholic beverage. Graduate students were found to consume EDs mixed with alcohol more often. Conclusions: The majority of students consumed EDs occasionally and while studying. Most side effects reported after consuming EDs were similar to previous findings. The higher consumption of EDs and of EDs mixed with alcohol by students in graduate programs could be explained by a higher and more complex study load requiring longer periods of wakefulness and concentration. Future studies looking at the consumption patterns of EDs in more competitive graduate programs such as medical and/or dentistry school should be considered.

Alcohol mixed with energy drink: Use may be a consequence of heavy drinking

AIMS

In recent years, studies have indicated that consumers of alcohol mixed with energy drink (AmED) are more likely to drink heavily and experience more negative consequences than consumers who avoid these beverages. Although researchers have identified a number of plausible hypotheses that explain how alcohol-energy drink co-ingestion could cause greater alcohol consumption, there has been no postulation about reverse causal relations. This paper identifies several plausible hypotheses for the observed associations between AmED consumption and greater alcohol consumption, and provides initial evidence for one such hypothesis suggesting that heavy drinking may be a determinant of AmED use.

METHOD

Data collected from 511bar patrons were used to examine the plausibility of one of the proposed hypotheses, i.e., AmED is an artifact of heavy drinking. Associations between the consumption of an assortment of alcoholic beverage types and total alcohol consumption were examined at the event-level, to assess whether AmED is uniquely related with greater alcohol consumption.

RESULTS

Increased alcohol consumption was associated with greater odds of consuming most alcoholic beverage types; this association was not unique to AmED.

CONCLUSIONS

Results support the overlooked hypothesis that AmED use is an artifact of heavy drinking. Thus, AmED consumption may be a consequence or marker of heavier drinking. Much of the existing research on alcoholic beverage types is limited in its ability to implicate any specific type of drink, including AmED, as a cause of increased alcohol consumption and related harm. More rigorous study designs are needed to examine causal relationships.