Inconsistencies Between Actual and Estimated Blood Alcohol Concentrations in a Field Study of College Students: Do Students Really Know How Much They Drink?

Investigating the relationship between inaccurate blood alcohol concentration estimates, harm and other negative consequences

INTRODUCTION

Alcohol-related harms place a significant burden on the Australian economy and health-care system. The current study aims to: (i) explore the relationship between blood alcohol concentration (BAC) and self-estimated blood alcohol concentration (EBAC); and (ii) determine whether BAC underestimation is related to an increased risk of experiencing physical aggression, verbal aggression, drink driving, ejection from a venue or refusal of service.

METHODS

Patron street surveys were conducted in four night-time entertainment precincts (NEP) across Queensland, Australia, between June 2016 and November 2018. Participants (N = 2144) reported on their EBAC and recent negative or harmful experiences in NEPs. BAC was measured via a breathalyser. Paired samples t tests were conducted to determine if patrons' BAC and EBAC were significantly different. Logistic regressions were conducted to examine whether BAC underestimation is a significant predictor of harm and negative outcomes.

RESULTS

Analyses identified a small, significant difference between patron's BAC and EBAC. Patrons with a low BAC were more likely to overestimate their BAC, while patrons with higher BACs were more likely to underestimate their BAC. Moderately intoxicated patrons had the most precise BAC estimations. Patrons with a high BAC and who underestimated their intoxication level were more likely to have been recently ejected from licensed venues, compared to accurate estimators or over-estimators.

DISCUSSION AND CONCLUSIONS

Overall, patrons are poor evaluators of their own intoxication level, which may have implications for their experiences in NEPs. The findings highlight the need for improved BAC education for patrons.

Alcohol demand as a predictor of drinking behavior in the natural environment

BACKGROUND AND AIMS

Alcohol demand, a measure of alcohol's reinforcing value, is associated with greater alcohol consumption and alcohol-related problems. Although alcohol demand has primarily been evaluated as a 'trait-like', individual difference measure, recent evidence indicates that demand exhibits meaningful short-term fluctuations. We aimed to determine whether moment-to-moment fluctuations in alcohol demand in individuals' natural drinking environments predicted drinking occurrence, drinking continuation, and drinking quantity.

DESIGN

Observational study.

SETTING

Individuals' natural drinking environments in Columbia, Missouri, USA.

PARTICIPANTS

Eighty-nine young adults (56% female; mean age = 24.8) participated from November 2018 to October 2020. Participants reported 14.5 drinking days [standard deviation (SD = 8.1)] and 4.1 drinks per occasion (SD = 2.5) during ecological momentary assessment (EMA).

MEASUREMENTS

Participants completed the alcohol purchase task at baseline. Following this, participants reported on their alcohol demand (breakpoint, O_max , intensity) and drinking behavior during EMA at daily, timed prompts from 6 p.m. to 2 a.m. They provided breathalyzer samples using a BACtrack Mobile® Pro. Models tested concurrent and prospective (lagged) associations between alcohol demand and drinking occurrence and drinking continuation after drinking initiation. Additional models tested concurrent associations between demand and breath alcohol concentrations (BrACs).

FINDINGS

Higher alcohol demand was associated with higher odds of drinking and continued drinking for all demand indices at the momentary [odds ratio (OR) = 1.27-1.56, ps ≤ 0.03] and day-level (OR = 2.14-3.39, ps < 0.001). Additionally, lagged demand predicted higher odds of drinking occurrence and continuation at the following prompt (OR = 1.32-1.53, ps ≤ 0.004). Higher alcohol demand was associated with higher BrACs at the momentary (bs = 0.0011-0.0026, ps ≤ 0.03) and day-level (bs = 0.0053-0.0062, ps < 0.001). At the person-level, findings varied depending on the demand measure.

CONCLUSIONS

Alcohol demand appears to be associated with both when and how much individuals drink in their natural drinking environments. Elevations in alcohol demand appear to be associated with increased likelihood of drinking and continuing to drink, and greater total alcohol consumption, both within and across drinking days.

Cholinergic and Neuroimmune Signaling Interact to Impact Adult Hippocampal Neurogenesis and Alcohol Pathology Across Development

Alcohol (ethanol) use and misuse is a costly societal issue that can affect an individual across the lifespan. Alcohol use and misuse typically initiates during adolescence and generally continues into adulthood. Not only is alcohol the most widely abused drug by adolescents, but it is also one of the most widely abused drugs in the world. In fact, high rates of maternal drinking make developmental ethanol exposure the most preventable cause of neurological deficits in the Western world. Preclinical studies have determined that one of the most consistent effects of ethanol is its disruption of hippocampal neurogenesis. However, the severity, persistence, and reversibility of ethanol’s effects on hippocampal neurogenesis are dependent on developmental stage of exposure and age at assessment. Complicating the neurodevelopmental effects of ethanol is the concurrent development and maturation of neuromodulatory systems which regulate neurogenesis, particularly the cholinergic system. Cholinergic signaling in the hippocampus directly regulates hippocampal neurogenesis through muscarinic and nicotinic receptor actions and indirectly regulates neurogenesis by providing anti-inflammatory regulatory control over the hippocampal environmental milieu. Therefore, this review aims to evaluate how shifting maturational patterns of the cholinergic system and its regulation of neuroimmune signaling impact ethanol’s effects on adult neurogenesis. For example, perinatal ethanol exposure decreases basal forebrain cholinergic neuron populations, resulting in long-term developmental disruptions to the hippocampus that persist into adulthood. Exaggerated neuroimmune responses and disruptions in adult hippocampal neurogenesis are evident after environmental, developmental, and pharmacological challenges, suggesting that perinatal ethanol exposure induces neurogenic deficits in adulthood that can be unmasked under conditions that strain neural and immune function. Similarly, adolescent ethanol exposure persistently decreases basal forebrain cholinergic neuron populations, increases hippocampal neuroimmune gene expression, and decreases hippocampal neurogenesis in adulthood. The effects of neither perinatal nor adolescent ethanol are mitigated by abstinence whereas adult ethanol exposure-induced reductions in hippocampal neurogenesis are restored following abstinence, suggesting that ethanol-induced alterations in neurogenesis and reversibility are dependent upon the developmental period. Thus, the focus of this review is an examination of how ethanol exposure across critical developmental periods disrupts maturation of cholinergic and neuroinflammatory systems to differentially affect hippocampal neurogenesis in adulthood.

Is Alcohol Consumption Associated with Poor Perceived Academic Performance? Survey of Undergraduates in Finland

The relationship between academic performance and alcohol consumption among students remains inconsistent. We assessed this relationship, controlling for sociodemographic characteristics across seven faculties at the University of Turku (1177 undergraduates). An online questionnaire assessed: seven sociodemographic characteristics (age, gender, year/discipline of study, accommodation type, being in intimate relationship, parental education, and income sufficiency); two perceived academic performance (students’ subjective importance of achieving good grades and students’ appraisal of their academic performance compared to peers); and six alcohol consumption behaviors (length of time, amount consumed, frequency, heavy episodic drinking, problem drinking, and possible alcohol dependence). Simple logistic regression assessed relationships between sociodemographic and academic variables with alcohol consumption behaviors; multiple logistic regression assessed the same relationships after controlling for all other variables. Students reported long duration and large amount of drinking (46% and 50%), high frequency of drinking (41%), heavy episodic drinking (66%), problem drinking (29%), and possible alcohol dependence (9%). After controlling, gender was associated with all alcohol consumption behaviors, followed by religiosity (associated with four alcohol behaviors), living situation, marital status, age (each associated with two alcohol behaviors), and parental education and year of study (each associated with one alcohol behavior). Study discipline, income sufficiency, importance of achieving good grades, and academic performance compared to peers were not associated with any alcohol behaviors. Universities need to assess problem drinking and alcohol use disorders among students. Prevention strategies are required to reduce risk. Health promotion efforts could focus on beliefs and expectations about alcohol and target student groups at risk for more efficient and successful efforts.

Assessment of Alcohol Use in the Natural Environment

The current article critically reviews 3 methodological options for assessing drinking episodes in the natural environment. Ecological momentary assessment (EMA) typically involves using mobile devices to collect self-report data from participants in daily life. This technique is now widely used in alcohol research, but investigators have implemented diverse assessment strategies. This article focuses on "high-resolution" EMA protocols that oversample experiences and behaviors within individual drinking episodes. A number of approaches have been used to accomplish this, including using signaled follow-ups tied to drinking initiation, asking participants to log entries before and after individual drinks or drinking episodes, and delivering frequent signaled assessments during periods of the day when alcohol use is most common. Transdermal alcohol sensors (TAS) are devices that are worn continuously and are capable of detecting alcohol eliminated through the skin. These methods are appealing because they do not rely upon drinkers' self-report. Studies using TAS have been appearing with greater frequency over the past several years. New methods are making the use of TAS more tractable by permitting back-translation of transdermal alcohol concentration data to more familiar estimates of blood alcohol concentration or breath alcohol concentration. However, the current generation of devices can have problems with missing data and tend to be relatively insensitive to low-level drinking. An emerging area of research investigates the possibility of using mobile device data and machine learning to passively detect the user's drinking, with promising early findings. EMA, TAS, and sensor-based approaches are all valid, and tend to produce convergent information when used in conjunction with one another. Each has a unique profile of advantages, disadvantages, and threats to validity. Therefore, the nature of the underlying research question must dictate the method(s) investigators select.

Alcohol-Induced Amnesia and Personalized Drinking Feedback: Blackouts Predict Intervention Response

Alcohol-induced amnesia ("blackout") is a reliable predictor of alcohol-related harm. Given its association with other negative consequences, experience of alcohol-induced amnesia may serve as a teachable moment, after which individuals are more likely to respond to intervention. To test this hypothesis, alcohol-induced amnesia was evaluated as a moderator of brief intervention effect on (a) alcohol-related consequences and (b) the proposed intervention mediators, protective behavioral strategies and peak blood alcohol concentration (BAC). Baseline alcohol risk measured using the Alcohol Use Disorders Identification Test (AUDIT) was also evaluated as a moderator to rule out the possibility that amnesia is simply an indicator of more general alcohol risk. College students (N = 198) reporting alcohol use in a typical week completed assessments at baseline and 1-month follow-up as part of a larger intervention trial. Participants were randomized to assessment only (AO; n = 58) or personalized feedback intervention (PFI; n = 140). Hierarchical regression was used to examine direct and indirect intervention effects. A significant group-by-amnesia interaction revealed that only PFI participants who had experienced alcohol-induced amnesia in the past month reported decreases in alcohol consequences at 1-month follow-up. The PFI reduced alcohol-related consequences indirectly through changes in peak BAC, but only among those who had experienced amnesia at baseline. In contrast, baseline alcohol risk (AUDIT) did not moderate intervention effects, and use of protective behavioral strategies did not statistically mediate intervention effects. Findings suggest that loss of memory for drinking events is a unique determinant of young adult response to brief alcohol intervention. Normative feedback interventions may be particularly effective for individuals who have experienced alcohol-induced amnesia in the past 30 days.

Distinctions in Alcohol-Induced Memory Impairment: A Mixed Methods Study of En Bloc Versus Fragmentary Blackouts

BACKGROUND

Blackouts-or memory loss for all or part of a drinking event-are reliable predictors of alcohol-related consequences. Studies suggest a distinction between en bloc (complete memory loss) and fragmentary (off-and-on memory loss) blackouts; however, research has not consistently differentiated between these 2 forms of blackout. This study aimed to validate the distinction between en bloc and fragmentary blackouts among young adults.

METHODS

Data were collected using qualitative (Study 1) and quantitative (Study 2) research methods. Participants in both studies were college students with a history of alcohol-induced memory impairment. They were recruited using community advertisement (Study 1, N = 50, 56% female) and Qualtrics survey panels (Study 2, N = 350, 56% female). Study 1 participants engaged in 8 focus groups. Discussions were audio-recorded, transcribed verbatim, and coded using applied thematic analysis. Findings guided assessment of en bloc and fragmentary blackout in Study 2. In Study 2, a separate sample of participants completed an online survey assessing drinking behavior, alcohol-induced memory impairment, and theoretical correlates of en bloc and fragmentary blackouts.

RESULTS

Study 1 participants differentiated between en bloc and fragmentary blackouts (which they referred to as "blackouts" and "brownouts," respectively) based on duration and extent of memory loss. They indicated that blackouts occur along a continuum, with en bloc "blackouts" at the extreme. They also stated that the term "blackout drinking" does not always imply memory loss. Study 2 participants reported higher rates of "brownouts" (81%) than "blackouts" (54%). They reported less negative outcome expectancies and attitudes, greater personal approval, higher prevalence estimates, lower self-efficacy, and stronger intentions for "brownouts" than "blackouts" (p < 0.001). Women perceived "blackouts/brownouts" as more prevalent than men and reported lower intentions to experience "blackouts" (p < 0.005).

CONCLUSIONS

Young adults are more permissive of fragmentary than en bloc blackout. En bloc blackouts may be a target for future interventions.

Blackouts as a Moderator of Young Adult Veteran Response to Personalized Normative Feedback for Heavy Drinking

BACKGROUND

Blackouts-or periods of alcohol-induced amnesia for all or part of a drinking event-have been identified as independent predictors of alcohol-related harm that may be used to identify individuals who would benefit from intervention. However, little is known about the prevalence and impact of blackouts among Veterans. This study examined blackouts as a moderator of young adult veteran response to a brief, online personalized normative feedback (PNF) intervention for heavy drinking.

METHODS

Veterans scoring ≥3/4 (women/men) on the Alcohol Use Disorders Identification Test completed a baseline and 1-month assessment as part of a larger intervention trial (N = 571; 83% male; age M = 28.9, SD = 3.3). Participants were randomized to alcohol PNF (n = 285) or a video game attention control (n = 286). Hierarchical regression was used to examine the interaction between intervention condition and blackouts on alcohol-related outcomes at 1-month follow-up.

RESULTS

At baseline, 26% of participants reported loss of memory for drinking events in the past 30 days. The interaction between condition and blackouts was significant, such that PNF participants who had experienced blackouts at baseline reported greater decreases in drinking quantity at 1 month than those who had not, and only PNF participants who had experienced baseline blackouts reported a decrease in alcohol problems at follow-up.

CONCLUSIONS

PNF appears to be particularly effective for individuals who have experienced alcohol-induced blackout, perhaps because blackouts prime them for feedback on their alcohol use. While other negative consequences may also prime individuals for behavior change, blackouts are posited as a particularly useful screening tool because they are prevalent among young adults, have a strong association with alcohol-related harm, and are assessed in widely used clinical measures.

Fuel-cell breathalyser use for field research on alcohol intoxication: an independent psychometric evaluation

Background

Several field studies have used fuel-cell breathalysers (FCB) to investigate the prevalence of alcohol intoxication. However, there is a lack of evidence evaluating the psychometric properties of these breathalysers outside of the forensic disciplines.

Methods

The current research describes four studies designed that assess the reliability and validity of portable platinum FCBs for research on alcohol intoxication. Utilising the Alcolizer LE5 breathalyser and, to a lesser degree, the Lifeloc FC-20 and the Lion Intoxilyzer 8000, each study sampled patrons frequenting popular night-time entertainment districts with varying levels of alcohol intoxication.

Results

Study one and two found excellent test-retest reliability and inter-instrument reliability for FCBs. Study three and four provided evidence to support the convergent validity of the two FCBs (the LE5 with the FC20), and with an evidential breathalyser (i.e., the Lion Intoxilyzer 8000; EB).

Discussion

A 93–97% agreement rate between breathalyser readings was found across the four studies. Portable FCB are recommended as a reliable and valid instrument for research designs requiring quick alcohol intoxication estimations in large populations. Strategies to enhance reliable and valid readings are provided for field researchers.

Development and validation of a model to predict blood alcohol concentrations: Updating the NHTSA equation

OBJECTS

To date, multiple models have been developed to estimate blood or breath alcohol concentration (BAC/BrAC). Several factors have been identified that affect the discrepancy between BACs/BrACs and retrospective estimation (eBAC) with existing equations. To the best of our knowledge, a model to quantify the effects of factors on the discrepancy between BAC/BrAC and eBAC is still nonexistent. The goal of this work was to develop a model to provide a more accurate retrospective estimation of breath alcohol concentration (eBAC).

METHOD

A laboratory study with alcohol consumption and a driving task was conducted with 30 participants (17 male and 13 female) to explore the factors that may contribute to the discrepancy between BrAC and eBAC obtained with existing models. A new eBAC model was developed to improve the estimation of BrAC by modeling effects of gender, weight, and the delay of BrAC measurement on the discrepancy. The validity of the model was tested and established with the data from the experiment conducted in this study and two published research studies, and compared with existing eBAC models.

RESULTS

Results of the model validity examination indicated that the developed model had higher R squares and lower root-mean-squared errors (RMSE) in estimating BrAC in three experiments compared with the existing eBAC models, including the NHTSA equation, the Matthew equation, the Lewis equation, the Watson equation, and the Forrest equation.

CONCLUSION

The developed eBAC model had a better performance of BrAC estimation compared with existing eBAC models. The validation of the model with the data from three empirical studies indicated a high level of generalizability in estimating BrAC.

Cross-Cultural Validity in Self-Reported Alcohol Use

BACKGROUND AND AIM

Little evidence is available on whether respondents from divergent sociocultural populations report alcohol consumption in systematically similar ways. Therefore, this study examined whether the validity of self-reported alcohol use differed between Arab and Jewish Israeli pub patrons.

METHODS

The analytical sample consisted of 227 Arab and 900 Jewish Israeli pub patrons who were approached as they left pubs and asked to record their Breath Alcohol Content (BrAC) value and complete a questionnaire that probed into their alcohol use. Validity of self-reported alcohol use across the 2 groups was examined by testing the discrepancy in concordance between the self-reported number of drinks and BrAC scores through simple Pearson correlations and by performing a multi-group measurement invariance (MI) comparison.

RESULTS

The Pearson correlation between the self-reported number of drinks and BrAC by the ethno-cultural group was almost identical across groups (Jews: r = 0.47, p < 0.01, df = 898; Arabs: r = 0.42, p < 0.01, df = 225). MI test results further confirmed that the factor loadings of the 2 drinking measures are similar across the 2 ethno-cultural groups.

CONCLUSIONS

Self-reported alcohol consumption gives cross-culturally valid and acceptable estimates of alcohol consumption in this sample of Israeli Arabs and Jews.

Drinkers' memory bias for alcohol picture cues in explicit and implicit memory tasks

BACKGROUND

Alcohol cues can bias attention and elicit emotional reactions, especially in drinkers. Yet, little is known about how alcohol cues affect explicit and implicit memory processes, and how memory for alcohol cues is affected by acute alcohol intoxication.

METHODS

Young adult participants (N=161) were randomly assigned to alcohol, placebo, or control beverage conditions. Following beverage consumption, they were shown neutral, emotional and alcohol-related pictures cues. Participants then completed free recall and repetition priming tasks to test explicit and implicit memory, respectively, for picture cues. Average blood alcohol concentration for the alcohol group was 74±13mg/dl when memory testing began. Two mixed linear model analyses were conducted to examine the effects of beverage condition, picture cue type, and their interaction on explicit and implicit memory.

RESULTS

Picture cue type and beverage condition each significantly affected explicit recall of picture cues, whereas only picture cue type significantly influenced repetition priming. Individuals in the alcohol condition recalled significantly fewer pictures than those in other conditions, regardless of cue type. Both free recall and repetition priming were greater for emotional and alcohol-related cues compared to neutral picture cues. No interaction effects were detected.

CONCLUSIONS

Young adult drinkers showed enhanced explicit and implicit memory processing of alcohol cues compared to emotionally neutral cues. This enhanced processing for alcohol cues was on par with that seen for positive emotional cues. Acute alcohol intoxication did not alter this preferential memory processing for alcohol cues over neutral cues.

Alcohol Brief Intervention in a university setting: A small-scale experimental study

Alcohol misuse among university students is commonplace. This study aimed to assess whether Alcohol Brief Intervention would be effective in reducing hazardous alcohol consumption in students compared to an alcohol information leaflet. Participants ( n = 125) assessed as higher risk drinkers using the Alcohol Use Disorders Identification Test Consumption were randomly assigned to receive an Alcohol Brief Intervention ( n = 67) or an information leaflet ( n = 58), with 82 (66%) completing a follow-up assessment. Alcohol consumption ( F(1, 80) = 14.52, p < 0.001) and the Alcohol Use Disorders Identification Test Consumption scores ( F(1, 80) = 23.63, p < 0.001) significantly decreased in both groups post-intervention; however, the groups did not significantly differ. Further research is recommended.

The temporal "pulse" of drinking: Tracking 5 years of binge drinking in emerging adults

Binge drinking is associated with clinically significant individual-level and public health consequences. The topography of binge drinking may influence the emergence of consequences, but studies of topography require a higher level of temporal resolution than is typically available in epidemiological research. To address topography across the 5 "peak" years of binge drinking (18 to 23 years), we assessed daily binge drinking via successive 90-day timeline follow-back interviews of 645 young adults (resulting in almost 700,000 data points). Results showed a weekend "pulse" of binge drinking that remained consistent across the entire 5 year span, with occasional holiday-based perturbations. Two-part latent growth curve modeling applied to this dataset showed that the often-observed decrease in drinking associated with "maturing out" was due more to decreased participation in binge drinking occasions, rather than to amounts consumed when drinking (intensity). Similarly, the number of binge drinkers varied by day of the week, but the intensity of binge drinking, for those drinking, varied little by day of the week. This approach also showed distinctive predictors for participation and intensity; baseline expectancies and sociability accounted for individual differences in participation, whereas impulsivity-sensation seeking predicted intensity. Individual patterns of binge drinking participation and intensity also predicted drinking consequences over the 5 years of the study. Given these results, binge drinking patterns may serve as a useful phenotype for future research on pathological drinking.

Diagnostic accuracy study of three alcohol breathalysers marketed for sale to the public

OBJECTIVES

To assess the diagnostic accuracy of three personal breathalyser devices available for sale to the public marketed to test safety to drive after drinking alcohol.

DESIGN

Prospective comparative diagnostic accuracy study comparing two single-use breathalysers and one digital multiuse breathalyser (index tests) to a police breathalyser (reference test).

SETTING

Establishments licensed to serve alcohol in a UK city.

PARTICIPANTS

Of 222 participants recruited, 208 were included in the main analysis. Participants were eligible if they were 18 years old or over, had consumed alcohol and were not intending to drive within the following 6 h.

OUTCOME MEASURES

Sensitivity and specificity of the breathalysers for the detection of being at or over the UK legal driving limit (35 µg/100 mL breath alcohol concentration).

RESULTS

18% of participants (38/208) were at or over the UK driving limit according to the police breathalyser. The digital multiuse breathalyser had a sensitivity of 89.5% (95% CI 75.9% to 95.8%) and a specificity of 64.1% (95% CI 56.6% to 71.0%). The single-use breathalysers had a sensitivity of 94.7% (95% CI 75.4% to 99.1%) and 26.3% (95% CI 11.8% to 48.8%), and a specificity of 50.6% (95% CI 40.4% to 60.7%) and 97.5% (95% CI 91.4% to 99.3%), respectively. Self-reported alcohol consumption threshold of 5 UK units or fewer had a higher sensitivity than all personal breathalysers.

CONCLUSIONS

One alcohol breathalyser had sensitivity of 26%, corresponding to false reassurance for approximately three people in four who are over the limit by the reference standard, at least on the evening of drinking alcohol. The other devices tested had 90% sensitivity or higher. All estimates were subject to uncertainty. There is no clearly defined minimum sensitivity for this safety-critical application. We conclude that current regulatory frameworks do not ensure high sensitivity for these devices marketed to consumers for a decision with potentially catastrophic consequences.

Ghrelin-Derived Peptides: A Link between Appetite/Reward, GH Axis, and Psychiatric Disorders?

Psychiatric disorders are often associated with metabolic and hormonal alterations, including obesity, diabetes, metabolic syndrome as well as modifications in several biological rhythms including appetite, stress, sleep-wake cycles, and secretion of their corresponding endocrine regulators. Among the gastrointestinal hormones that regulate appetite and adapt the metabolism in response to nutritional, hedonic, and emotional dysfunctions, at the interface between endocrine, metabolic, and psychiatric disorders, ghrelin plays a unique role as the only one increasing appetite. The secretion of ghrelin is altered in several psychiatric disorders (anorexia, schizophrenia) as well as in metabolic disorders (obesity) and in animal models in response to emotional triggers (psychological stress …) but the relationship between these modifications and the physiopathology of psychiatric disorders remains unclear. Recently, a large literature showed that this key metabolic/endocrine regulator is involved in stress and reward-oriented behaviors and regulates anxiety and mood. In addition, preproghrelin is a complex prohormone but the roles of the other ghrelin-derived peptides, thought to act as functional ghrelin antagonists, are largely unknown. Altered ghrelin secretion and/or signaling in psychiatric diseases are thought to participate in altered appetite, hedonic response and reward. Whether this can contribute to the mechanism responsible for the development of the disease or can help to minimize some symptoms associated with these psychiatric disorders is discussed in the present review. We will thus describe (1) the biological actions of ghrelin and ghrelin-derived peptides on food and drugs reward, anxiety and depression, and the physiological consequences of ghrelin invalidation on these parameters, (2) how ghrelin and ghrelin-derived peptides are regulated in animal models of psychiatric diseases and in human psychiatric disorders in relation with the GH axis.

Student drinking patterns and blood alcohol concentration on commercially organised pub crawls in the UK

BACKGROUND

Commercial student pub crawls are associated with high levels of alcohol consumption, and are of growing concern amongst public health and student bodies. However, little is currently known about drinking behaviours whilst participating in these events.

METHODS

A questionnaire was implemented amongst 227 students attending commercial pub crawls across three UK events. Questions established alcohol consumption patterns up to the point of interview and throughout the remaining night out, and pub crawl experience. Breathalyser tests were used to measure breath alcohol concentration (converted to blood alcohol concentration [BAC]) at interview. Analyses used chi squared, Mann-Whitney U, Kruskal-Wallis and logistic regression.

RESULTS

94.3% of participants had consumed alcohol, 90.9% of whom reported preloading. Drinkers reported consuming a median of 10.0 alcohol units (80g of pure alcohol) up to the point of interview (range one-40.6), with estimated total consumption over the evening exceeding 16units (range three-70.6). Median BAC of drinkers at the time of interview was 0.10%BAC (range 0.00-0.27). High BAC (>0.08%; at interview) was associated with having not eaten food in the four hours prior (AOR 4.8, p<0.01), time spent drinking (AOR 1.4, p<0.01) and number of units drank per hour (AOR 1.2, p<0.01).

CONCLUSIONS

Measures to prevent high levels of alcohol consumption before and during commercial pub crawls should aim to alter drinking behaviours such as preloading and rapid and excessive drinking. Organisers, local authorities, universities and students should all be involved in ensuring the effective management of pub crawls, including implementation of harm prevention measures.

Do Objective Measures of Blood Alcohol Concentrations Make More Sense than Self-reports in Emergency Department Studies?

PURPOSE

: Concerns about self-reports have led to calls for objective measures of blood alcohol concentration (BAC). The present study compared objective measures with self-reports.

METHODS

: BAC from breath or blood samples were obtained from 272 randomly sampled injured patients who were admitted to a Swiss emergency department (ED). Self-reports were compared a) between those providing and refusing a BAC test, and b) to estimated peak BAC (EPBAC) values based on BACs using the Widmark formula.

RESULTS

: Those providing BACs were significantly (P < 0.05) younger, more often male, and less often reported alcohol consumption before injury, but consumed higher quantities when drinking. Eighty-eight percent of those with BAC measures gave consistent reports (positive or negative). Significantly more patients reported consumption with negative BAC measures (N = 29) than vice versa (N = 3). Duration of consumption and times between injury and BAC measurement predicted EPBAC better than did the objective BAC measure.

CONCLUSIONS

: There is little evidence that patients who provide objective BAC measures deliberately conceal consumption. ED studies must rely on self-reports, eg, take the time period between injury and ED admission into account. Clearly, objective measures are of clinical relevance, eg, to provide optimal treatment in the ED. However, they may be less relevant to establishing effects in an epidemiologic sense, such as estimating risk relationships. In this respect, efforts to increase the validity and reliability of self-reports should be preferred over the collection of additional objective measures.

Breath alcohol concentrations of designated drivers

OBJECTIVE

This study established breath alcohol concentrations (BrACs) and alcohol-related behaviors of designated drivers (DDs) to determine (a) whether DDs are abstaining from drinking, (b) whether alcohol-related behaviors of non-DDs and DDs were different, and (c) whether the alcohol consumption of DDs resulted in BrAC levels that affected driving performance or caused psychomotor impairment.

METHOD

We conducted six anonymous field studies during a 3-month period in a southeastern college community restaurant and bar district. Intercept interviews were conducted with 1,071 bar patrons. Alcohol-related behaviors, BrAC, and whether one was serving as a DD were measured. The sample was primarily White (72.7%), male (62.4%) college students (64.7%). Descriptive statistics and an independent sample t test compared the BrACs of DDs versus non-DDs. A one-way analysis of variance examined the differences in the alcohol-related behaviors (Alcohol Use Disorders Identification Test-consumption [AUDIT-C] score) across DDs abstaining from drinking (BrAC = .00 g/210 L), drinking DDs (BrACs ≥ .02 and < .05 g/210 L), and impaired DDs (BrACs ≥ .05 g/210 L). A logistic regression assessed the impact of alcohol-related behaviors (AUDIT-C) on whether one was serving as a DD.

RESULTS

Of the 165 DDs, approximately 40% did not abstain from drinking. Approximately 17% of DDs had BrACs between .02 g/210 L and .049 g/210 L, whereas 18% recorded BrACs at .05 g/210 L or greater. The mean AUDIT-C score for impaired DDs significantly differed from both abstaining DDs and drinking DDs. Participants with greater AUDIT-C scores were more likely to serve as a DD and have a BrAC that significantly inhibited driving ability and psychomotor function.

CONCLUSIONS

These findings identify the need for consensus across researcher, layperson, and communication campaigns that a DD must be someone who has abstained from drinking entirely.

Memory for emotional picture cues during acute alcohol intoxication

OBJECTIVE

Memory affects behavior by allowing events to be anticipated and goals to be planned based on previous experiences. Emotional memory, in particular, is thought to play a central role in behavior in general and in drinking behavior in particular. Alcohol intoxication has been shown to disrupt intentional, conscious memory, but not unintentional, implicit memory for neutral stimuli; however, its effects on emotional memory are not well understood. This study examined whether alcohol intoxication affected memory for emotionally valenced stimuli by testing explicit recall and implicit repetition priming of emotional picture cues.

METHOD

Participants were 36 young adults (21-24 years old, 16 women) who received an alcohol, placebo, or no-alcohol beverage. Both cue exposure and memory testing occurred after beverage consumption (i.e., during intoxication for the alcohol group).

RESULTS

Alcohol intoxication impaired explicit recall of all cue types but did not impair implicit repetition priming. Emotionally negative and positive cues were more often recalled compared with neutral cues across all beverage groups, and emotionally negative cues demonstrated more priming than emotionally positive or neutral cues in all beverage groups.

CONCLUSIONS

Alcohol intoxication disrupted effortful recall of all cues, although the relative memory advantage of emotionally valenced over-neutral stimuli remained even after drinking. The effects of alcohol on unintentional memory priming were not statistically significant, but the effects of emotionally negative cues were. Further research is needed to better understand alcohol intoxication and emotional valence effects on memory processes during implicit memory tasks and the possibility that negative mood facilitates memory priming of negative emotional stimuli.

Self-estimation of blood alcohol concentration: a review

This article reviews the history of blood alcohol concentration (BAC) estimation training, which trains drinkers to discriminate distinct BAC levels and thus avoid excessive alcohol consumption. BAC estimation training typically combines education concerning alcohol metabolism with attention to subjective internal cues associated with specific concentrations. Estimation training was originally conceived as a component of controlled drinking programs. However, dependent drinkers were unsuccessful in BAC estimation, likely due to extreme tolerance. In contrast, moderate drinkers successfully acquired this ability. A subsequent line of research translated laboratory estimation studies to naturalistic settings by studying large samples of drinkers in their preferred drinking environments. Thus far, naturalistic studies have provided mixed results regarding the most effective form of BAC feedback. BAC estimation training is important because it imparts an ability to perceive individualized impairment that may be present below the legal limit for driving. Consequently, the training can be a useful component for moderate drinkers in drunk driving prevention programs.

Subjective measures of binge drinking and alcohol-specific adverse health outcomes: a prospective cohort study

AIM

To determine the performance of subjectively defined intoxications, hangovers and alcohol-induced pass-outs in identifying drinkers at risk for adverse health outcomes.

DESIGN

Prospective population-based cohort study.

SETTING

Working-aged Finnish general population.

PARTICIPANTS

A total of 21,204 alcohol-drinking men and women aged 20-24, 30-34, 40-44 and 50-54 years at baseline who participated in the Health and Social Support (HeSSup) postal survey in 1998.

MEASUREMENTS

Binge drinking was measured by subjectively defined intoxications/drunkenness, hangovers and alcohol-induced pass-outs. Hazardous drinking was defined according to Finnish guidelines as weekly total intake of >287 g of ethanol for men, and for women > 191 g of ethanol (≥24 and ≥16 standard drinks, respectively). Study participants were followed-up for 7 years for alcohol-specific hospitalizations and deaths. Proportional hazard models and areas under the receiver operating characteristics curves (AUC) were used to analyse the data.

FINDINGS

Of the drinkers, 6.5% exceeded the weekly limit for hazardous drinking, and 1.5% experienced the alcohol-specific end-point during the follow-up. Subjective intoxications, hangovers and alcohol-induced pass-outs all predicted future alcohol-specific diagnoses independently of average intake and of several other potential confounders. In identifying baseline hazardous drinking, subjective intoxications had a superior performance in relation to other subjective measures of binge drinking. In identifying future alcohol-specific hospitalizations or death, subjective intoxications had also the best performance, but this was not significantly different from the other binge drinking measures, or average intake.

CONCLUSIONS

Subjectively defined intoxications, hangovers and alcohol-induced pass-outs are population-level proxy measures of at-risk drinking patterns.

Public house patrons' engagement in hypothetical sexual assault: a test of Alcohol Myopia Theory in a field setting

Previous research has found that drinking establishments are often antecedent to sexual aggression outcomes. In this study, male participants were randomly selected from public houses (i.e., "pubs") and asked to imagine themselves in a hypothetical intimate encounter in which the female in the scenario stops consenting to sexual contact. Participants were given the option to continue making sexual advances up to and including sexual intercourse against the woman's will. It was hypothesized based on Alcohol Myopia Theory that participant blood alcohol concentration (BAC) levels would be associated with hypothetical sexual aggression when stereotypical cues of a woman's sexual availability (revealing clothing and alcohol use) were present in the scenario. Men's engagement in hypothetical sexual aggression was associated with BAC levels, but only when the woman was wearing revealing clothing. The sobriety of the female actor was not associated with sexual aggression. Results indicate that Alcohol Myopia Theory generalizes to a field setting.

Current drinking and health-risk behaviors among male high school students in central Thailand

Background

Alcohol drinking is frequently related to behavioral problems, which lead to a number of negative consequences. This study was to evaluate the characteristics of male high school students who drink, the drinking patterns among them, and the associations between current drinking and other health risk behaviors which focused on personal safety, violence-related behaviors, suicide and sexual behaviors.

Method

A cross-sectional study was conducted to explore current alcohol drinking and health-risk behaviors among male high school students in central Thailand. Five thousand one hundred and eighty four male students were classified into 2 groups according to drinking in the previous 30 days (yes = 631, no = 4,553). Data were collected by self-administered, anonymous questionnaire which consisted of 3 parts: socio-demographic factors, health-risk behaviors and alcohol drinking behavior during the past year from December 2007 to February 2008.

Results

The results showed that the percent of current drinking was 12.17. Most of them were 15-17 years (50.21%). Socio-demographic factors such as age, educational level, residence, cohabitants, grade point average (GPA), having a part time job and having family members with alcohol/drug problems were significantly associated with alcohol drinking (p < 0.05). Multiple logistic regression analysis, after adjusting for socio-demographic factors, revealed that health-risk behavioral factors were associated with current alcohol consumption: often drove after drinking alcohol (OR = 3.10, 95% CI = 1.88-5.12), often carried a weapon (OR = 3.51, 95% CI = 2.27-5.42), often got into a physical fight without injury (OR = 3.06, 95% CI = 1.99-4.70), dating violence (OR = 2.58, 95% CI = 1.79-3.71), seriously thought about suicide (OR = 2.07, 95% CI = 1.38-3.11), made a suicide plan (OR = 2.10, 95% CI = 1.43-3.08), ever had sexual intercourse (OR = 5.62, 95% CI = 4.33-7.29), alcohol or drug use before last sexual intercourse (OR = 2.55, 95% CI = 1.44-4.53), and got someone pregnant (OR = 3.99, 95% CI = 1.73-9.25).

Conclusions

An increased risk of health-risk behaviors, including driving vehicles after drinking, violence-related behaviors, sad feelings and attempted suicide, and sexual behaviors was higher among drinking students that led to significant health problems. Effective intervention strategies (such as a campaign mentioning the adverse health effects and social consequences to the risk groups, and encouraging parental and community efforts to prevent drinking) among adolescents should be implemented to prevent underage drinking and adverse consequences.

Cross-sectional measures and modelled estimates of blood alcohol levels in UK nightlife and their relationships with drinking behaviours and observed signs of inebriation

BACKGROUND

Management of nightlife in UK cities focuses on creating safe places for individuals to drink. Little is known about intoxication levels as measuring total alcohol consumption on nights out is complicated by early evening interviews missing subsequent consumption and later interviews risking individuals being too drunk to recall consumption or participate at all. Here we assess mixed survey and modelling techniques as a methodological approach to examining these issues.

METHODS

Interviews with a cross sectional sample of nightlife patrons (n = 214) recruited at different locations in three cities established alcohol consumption patterns up to the point of interview, self-assessed drunkenness and intended drinking patterns throughout the remaining night out. Researchers observed individuals' behaviours to independently assess drunkenness. Breath alcohol tests and general linear modelling were used to model blood alcohol levels at participants' expected time of leaving nightlife settings.

RESULTS

At interview 49.53% of individuals regarded themselves as drunk and 79.43% intended to consume more alcohol before returning home, with around one in ten individuals (15.38% males; 4.35% females) intending to consume >40 units (equal to 400 mls of pure alcohol). Self-assessed drunkenness, researcher observed measures of sobriety and blood alcohol levels all correlated well. Modelled estimates for blood alcohol at time of going home suggested that 71.68% of males would be over 0.15%BAC (gms alcohol/100 mls blood). Higher blood alcohol levels were related to drinking later into the night.

CONCLUSIONS

UK nightlife has used substantive health and judicial resources with the aim of creating safer and later drinking environments. Survey and modelling techniques together can help characterise the condition of drinkers when using and leaving these settings. Here such methods identified patrons as routinely getting drunk, with risks of drunkenness increasing over later nights. Without preventing drunkenness and sales to intoxicated individuals, extended drinking hours can simply act as havens for drunks. A public health approach to nightlife is needed to better understand and take into account the chronic effects of drunkenness, the damages arising after drunk individuals leave city centres and the costs of people avoiding drunken city centres at night.

The relationship between self-reported drinking and BAC level in emergency room injury cases: is it a straight line?

BACKGROUND

While the validity of self-reported consumption based on blood alcohol concentration (BAC) has been found to be high in emergency room (ER) samples, little research exists on the estimated number of drinks consumed given a BAC level. Such data would be useful in establishing a dose-response relationship between drinking and risk (e.g., of injury) in those studies for which the number of drinks consumed is not available but BAC is.

METHODS

Several methods were used to estimate the number of drinks consumed in the 6 hours prior to injury based on BAC obtained at the time of ER admission of n = 1,953 patients who self-reported any drinking 6 hours prior to their injury and who arrived to the ER within 6 hours of the event, from the merged Emergency Room Collaborative Alcohol Analysis Project (ERCAAP) and the World Health Organization Collaborative Study on Alcohol and Injury across 16 countries.

RESULTS

The relationship between self-reported consumption and averaged BAC within each consumption level appeared to be fairly linear up to about 7 drinks and a BAC of approximately 100 mg/dl. Above about 7 reported drinks, BAC appeared to have no relationship with drinking, possibly representing longer consumption periods than only the 6 hours before injury for those reporting higher quantities consumed. Both the volume estimate from the bivariate BAC to self-report relationship as well as from a Widmark calculation using BAC and time from last drink to arrival to the ER indicated a somewhat weak relationship to actual number of self-reported drinks.

CONCLUSIONS

Future studies may benefit from investigating the factors suspected to be driving the weak relationships between these measures, including the actual time over which the reported alcohol was consumed and pattern of drinking over the consumption period.

Prevalence and patterns of alcohol consumption and health-risk behaviors among high school students in Thailand

BACKGROUND

Underage drinking is a significant social and public health problem in Thailand. We report the prevalence and patterns of alcohol consumption and associated health-risk behaviors using data from a 2007-2008 national school survey.

METHOD

A cross-sectional survey using a self-administered questionnaire was conducted among 50,033 high school and vocational college students from 201 schools in 40 provinces between December 2007 and February 2008.

RESULTS

The prevalence rates of past-year drinking, past-30-day binge drinking, and drinking until intoxication were 25.5, 9.5, and 17.3% in boys and 14.5, 3.7, and 7.2% in girls, respectively. Higher school levels, lower grades, living with someone other than their own parents, and having family members with substance or alcohol problems were significantly associated with all kinds of drinking. Binge drinkers were significantly more likely to have drinking consequences, e.g., driving after drinking, nausea and vomiting, and having a hangover than were nonbinge drinkers. The rates of other behavior and emotional problems were 2.5 to 6.7 times as likely in drinkers as nondrinkers, including smoking (35.1% vs. 4.9%), prescription drug misuse (17.7% vs. 6.7%), illicit substance use (17.8% vs. 2.4%), carrying a weapon (6.5% vs. 1.8%), feeling depressed (23.2% vs. 10.9%), suicidal attempt (10.5% vs. 3.8%), and sexual intercourse (30.5% vs. 5.7%).

CONCLUSION

Alcohol consumption is a serious problem among adolescents in Thailand and is strongly associated with various health-risk behaviors. Effective age- and gender-specific interventions should be implemented to discourage underage drinking and associated adverse health and social consequences.

Airline passengers' alcohol use and its safety implications

BACKGROUND

This investigation was designed to identify individual and contextual factors associated with airline passengers' alcohol use, and to explore potentially dangerous in-flight alcohol consumption.

METHODS

Passengers waiting to board 24 domestic flights at an international airport in the South Atlantic United States were asked to complete an anonymous questionnaire. Eighty percent of those approached agreed to participate. Our findings are based upon the responses of 1,548 adults.

RESULTS

A majority (84%) of passengers indicated that they did not intend to consume alcoholic beverages on the plane they were waiting to board. Passengers who were more likely to report that they would drink were on longer flights, traveling with friends, and anticipating First or Business Class seating. Passengers who had already consumed alcohol that day and those who drank more often generally were also more likely to say that they intended to consume alcohol, as were people who thought that in-flight alcohol use was enjoyable, acceptable, and unlikely to make jet lag worse. Eighty-nine percent of the passengers who said they intended to drink reported that they would purchase one to two drinks.

CONCLUSIONS

Very few respondents reported intentions that would pose a risk to others. Future studies should validate alcohol consumption and sample passengers at multiple airports throughout the year.

Common ground: an investigation of environmental management alcohol prevention initiatives in a college community

OBJECTIVE

This article presents an evaluation of Common Ground, a media campaign-supported prevention program featuring increased enforcement, decreased alcohol access, and other environmental management initiatives targeting college student drinking.

METHOD

Phase 1 of the media campaign addressed student resistance to environmentally focused prevention by reporting majority student support for alcohol policy and enforcement initiatives. Phase 2 informed students about state laws, university policies, and environmental initiatives. We conducted student telephone surveys, with samples stratified by gender and year in school, for 4 consecutive years at the intervention campus and 3 years at a comparison campus. We did a series of one-way between-subjects analyses of variance and analyses of covariance, followed by tests of linear trend and planned comparisons. Targeted outcomes included perceptions of enforcement and alcohol availability, alcohol use, and alcohol-impaired driving. We examined archived police reports for student incidents, primarily those resulting from loud parties.

RESULTS

There were increases at the intervention campus in students' awareness of formal alcohol-control efforts and perceptions of the alcohol environment, likelihood of apprehension for underage drinking, consequences for alcohol-impaired driving, and responsible alcohol service practices. There were decreases in the perceived likelihood of other students' negative behavior at off-campus parties. Police-reported incidents decreased over time; however, perceived consequences for off-campus parties decreased. No changes were observed for difficulty finding an off-campus party, self-reported alcohol use, or alcohol-impaired driving.

CONCLUSIONS

The intervention successfully altered perceptions of alcohol enforcement, alcohol access, and the local alcohol environment. This study provides important preliminary information to researchers and practitioners engaged in collaborative prevention efforts in campus communities.

The feasibility and effectiveness of a web-based personalised feedback and social norms alcohol intervention in UK university students: a randomised control trial

OBJECTIVE

Alcohol misuse amongst University students is a serious concern, and research has started to investigate the feasibility of using e-health interventions. This study aimed to establish the effectiveness of an electronic web-based personalised feedback intervention through the use of a randomised control trial (RCT).

METHODS

506 participants were stratified by gender, age group, year of study, self-reported weekly consumption of alcohol and randomly assigned to either a control or intervention condition. Intervention participants received electronic personalised feedback and social norms information on their drinking behaviour which they could access by logging onto the website at any time during the 12-week period. CAGE score, average number of alcoholic drinks consumed per drinking occasion, and alcohol consumption over the last week were collected from participants at pre- and post-survey.

RESULTS

A significant difference in pre- to post-survey mean difference of alcohol consumed per occasion was found, with those in the intervention condition displaying a larger mean decrease when compared to controls. No intervention effect was found for units of alcohol consumed per week or for CAGE scores. Sixty-three percent of intervention participants agreed that the feedback provided was useful. Those intervention participants who were above the CAGE cut off were more likely to report that the website would make them think more about the amount they drank.

CONCLUSIONS

Delivering an electronic personalised feedback intervention to students via the World Wide Web is a feasible and potentially effective method of reducing student alcohol intake. Further research is needed to replicate this outcome, evaluate maintenance of any changes, and investigate the process of interaction with web-based interventions.

Heart rate variability response to alcohol, placebo, and emotional picture cue challenges: effects of 0.1-Hz stimulation

Heart rate variability (HRV) supports emotion regulation and is reduced by alcohol. Based on the resonance properties of the cardiovascular system, a new 0.1-Hz methodology was developed to present emotional stimuli and assess HRV reaction in participants (N=36) randomly assigned to an alcohol, placebo, or control condition. Blocked picture cues (negative, positive, neutral) were presented at a rate of 5 s on, 5 s off (i.e., 0.1-Hz frequency). SDNN, pNN50, and HF HRV were reduced by alcohol, compared to the placebo and control. The 0.1-Hz HRV index was diminished by alcohol and placebo, suggesting that autonomic regulation can be affected by cognitive expectancy. The 0.1-Hz HRV index and pNN50 detected changes in arousal during emotional compared to neutral cues, and the 0.1-Hz HRV index was most sensitive to negative valence. The 0.1-Hz HRV methodology may be useful for studying the intersection of cognition, emotion, and autonomic regulation.

Emotional intelligence: a moderator of perceived alcohol peer norms and alcohol use

This study investigated the roles of emotional intelligence and perceived alcohol peer norms in relation to alcohol use. Two hundred and forty-two undergraduates completed the Campus Survey of Alcohol and Other Drug Norms (Core Institute, 1997) and the Emotional Intelligence Scale (Schutte, Malouff, Hall, Haggerty, & Cooper, 1998). Contrary to emerging research findings, emotional intelligence (EI) was not directly associated with the study's alcohol-use variables. However, the moderating role of EI was supported in the relationship between perceived alcohol peer norms and students' alcohol use. Among college students with lower EI, there was a significantly stronger association between these variables, compared to students with higher EI.

Partying before the party: examining prepartying behavior among college students

OBJECTIVE

The authors examined the phenomenon known to college students as prepartying, which is the consumption of alcohol prior to attending an event or activity (eg, party, bar, concert) at which more alcohol may be consumed.

PARTICIPANTS

To explore the extent of this behavior, the authors surveyed 227 college students about each drinking event over a 1-month period.

RESULTS

Principal results revealed that 64% of participants engaged in prepartying (75% of drinkers) and that prepartying is involved in approximately 45% of all drinking events. Prepartying was predictive of more drinking throughout the day of the drinking event and alcohol-related negative consequences. Men and women engaged in this behavior at similar rates, and prepartying was most related to social reasons for drinking.

CONCLUSION

Because prepartying is well-known among students, the authors suggest that clinicians and researchers target it to better understand college drinking and to help students understand the associated dangers.

Gender differences in plasma ghrelin and its relations to body composition and bone - an opposite-sex twin study

BACKGROUND

Ghrelin, a peptide hormone that plays a role in the regulation of appetite and body adiposity, may also play a role in bone metabolism.

OBJECTIVES

We used the opposite-sex twin model to study associations of plasma ghrelin levels with measures of bone mass and body composition, and determine how such associations were influenced by gender and age.

PATIENTS AND MEASUREMENTS

We measured total plasma ghrelin by radioimmunoassay (RIA) and bone mass/body composition parameters by dual energy X-ray absorptiometry in 79 pairs of opposite sex twins (n = 158 subjects). To examine the effect of age, the study population was divided by median age into two groups: under 51.2 years (38 pairs) and over 51.2 years (41 pairs).

RESULTS

Women had higher plasma ghrelin levels than men (median 1063 vs. 869 ng/l, P < 0.01). Age was a significant predictor of plasma ghrelin levels after adjustment for gender, fat mass and body size. In the older age group, plasma ghrelin levels were inversely associated with fat mass measures in men and women, but there were gender differences in the nature of these associations. In women, plasma ghrelin correlated inversely with body mass index (BMI, r = -0.32), total fat mass (r = -0.30) and fat mass/lean mass ratio (r = -0.42), whereas in men associations with abdominal fat mass (r = -0.31) and fat distribution index (r = -0.33) were observed. Plasma ghrelin was associated with alcohol consumption in older men and women. In the obese subgroup (BMI > 30) no significant gender differences in plasma ghrelin were found. Plasma ghrelin levels were not significantly associated with bone mineral density (BMD) generally, except for hip BMD in younger women (r = -0.39).

CONCLUSION

Plasma ghrelin levels are associated with age, gender, alcohol intake and fat mass measures but only weakly to bone mass measures.

Correlation between serum ghrelin levels and cocaine-seeking behaviour triggered by cocaine-associated conditioned stimuli in rats

Ghrelin is a brain-gut peptide with growth hormone-releasing and appetite-inducing activities. A growing body of evidence suggests that ghrelin may affect the central reward system and modulate the activity of the mesolimbic system. Recent clinical studies also showed a significant positive correlation between plasma ghrelin levels and craving in alcoholics. Accordingly, the present study investigated the potential role of serum ghrelin levels in the reinstatement of cocaine-seeking behaviour triggered by cocaine-associated cues. In addition, serum corticosterone levels were determined in the light of evidence suggesting that corticosterone plays a modulatory role in cocaine-seeking behaviour. Male Lister Hooded rats under a restricted diet regime were first trained to intravenously self-administer cocaine under a fixed ratio-1 schedule of reinforcement. Conditioned stimuli (CS: tone and cue-light on for 5 seconds) were presented contingently with cocaine delivery. Once a stable baseline of cocaine self-administration was observed, lever presses were extinguished to less than 30% of baseline rates by removing both cocaine and CS. Reinstatement of responding was then induced by re-exposure to cocaine-associated CS. Blood samples for the enzyme immunoassay determination of serum ghrelin and the radioimmunoassay determination of serum corticosterone levels were collected 30 minutes before the beginning of reinstatement sessions. Rats significantly reinstated their responding when exposed to CS. A positive and significant correlation was observed between ghrelin levels (r = 0.64; P < 0.05), but not corticosterone (r = 0.37; NS), and the increased active lever presses only in animals exposed to CS. These findings suggest a potential role of ghrelin in the modulation of cue-triggered reinstatement of cocaine-seeking behaviour.

Apomorphine-Induced Growth Hormone Response Is Attenuated by Ethanol but Not Dextromethorphan

BACKGROUND

Misuse of alcohol drinking is a major health problem. Alcohol decreases spontaneous growth hormone (GH) secretion, but the mechanism is unclear. The aim of this study was to test whether administration of alcohol (study 1) or a N-methyl d-aspartate (NMDA) receptor antagonist (study 2) attenuates the GH response to pharmacological dopaminergic stimulation.

METHODS

The 2-session repeated measures design was conducted at the endocrine laboratory at the Department of Psychiatry at the Free University Berlin. Twenty healthy Caucasian males aged 35+/-10 years without a history of alcohol use disorders were tested using the Apomorphine (APO) challenge test. In study 1, we injected APO (0.01 mg/kg s.c.) 1 hour after oral administration of 1 g/kg ethanol and placebo, respectively. In study 2, the APO challenge was conducted after 0.3 mg/kg dextromethorphan (DXM) and placebo. The main outcome measures were the peak serum GH concentration and area under the time/concentration curve up to 120 minutes after APO. The effects of ethanol and DXM were tested using the Wilcoxon signed-rank tests.

RESULTS

Compared with placebo, alcohol significantly decreased the APO-induced GH release (mean and SEM peak GH concentration 19.9+/-3.2 vs 6.2+/-1.9 ng/mL, p=0.002). Dextromethorphan did not change APO-induced GH response (22.5+/-5.4 vs 21.0+/-5.8 ng/mL, p=0.105).

CONCLUSION

A single intermediate alcohol dose markedly reduces GH response to dopaminergic stimulation. Although alcohol is thought to stimulate dopaminergic function in certain pathways, but not necessarily in the hypothalamus, our results are in line with the alcohol effect on baseline GH secretion. Growth hormone suppression appears not to be mediated by ethanol's NMDA-antagonistic properties.