The calculation of blood ethanol concentrations in males and females

Elucidating the alcohol-sleep-hangover relationship in college students using a daily diary approach

This daily diary study expands knowledge of the pharmacological alcohol-sleep relationship using a multilevel modeling approach. The interplay between alcohol and sleep on hangover susceptibility is also explored. College students (n = 337; 52 % female) provided 2976 days of self-reported alcohol use. We regressed sleep duration onto accumulated sleep debt, prior night sleep duration, and estimated blood alcohol concentration (eBAC) at bedtime; linear mixed models disaggregated day and person-level effects. Binomial models, assessing days after drinking when eBAC = 0 % versus when eBAC>0 % at waketime, regressed hangover susceptibility onto the same predictors plus sleep duration. More accumulated sleep debt predicted slightly longer same-night sleep. Greater than average bedtime intoxication predicted longer than average same-night sleep when drinking ceased early, but later drinking attenuated the relationship. People who typically stopped drinking later in the night reported typically shorter sleep durations on drinking nights. When waketime eBAC = 0 %, higher eBAC at bedtime and drinking later on a given night predicted greater next-day hangover susceptibility. Typical bedtime eBAC and typically later drinking predicted typically greater hangover susceptibility. When waketime eBAC>0 %, longer sleep duration predicted more likely hangovers. Bedtime eBAC and sleep debt interacted, such that more sleep debt attenuated the positive association between intoxication and next-day hangover susceptibility. Late-night drinking appeared to reduce sleep duration and increase hangover susceptibility. Accumulated sleep debt complicated the alcohol-sleep-hangover relationship. External factors influencing sleep behaviors were not assessed, but the results highlight the need to deconstruct sleep into acute and chronic processes. Future studies should better subdivide physiological processes related to hangovers.

Vitreoretinal surgical performance after acute alcohol consumption and hangover

AIM

Routine alcohol testing of practicing physicians remains controversial since there are no uniform guidelines or legal regulations in the medical field. Our aim was to quantitatively study the acute and next-morning effects of breath alcohol concentration (BAC)-adjusted alcohol intake on overall simulated surgical performance and microtremor among senior vitreoretinal surgeons.

METHODS

This prospective cohort study included 11 vitreoretinal surgeons (>10 years practice). Surgical performance was first assessed using the Eyesi surgical simulator following same-day alcohol consumption producing a BAC reading of 0.06%-0.10% (low-dose), followed by 0.11%-0.15% (high-dose). Dexterity was then evaluated after a 'night out' producing a high-dose BAC combined with a night's sleep. Changes in the total score (0-700, worst-best) and tremor (0-100, best-worst) were measured.

RESULTS

Surgeon performance declined after high-dose alcohol compared with low-dose alcohol (-8.60±10.77 vs -1.21±7.71, p=0.04, respectively). The performance during hangover was similar to low-dose alcohol (-1.76±14.47 vs -1.21±7.71, p=1.00, respectively). The performance during hangover tended to be better than after high-dose alcohol (-1.76±14.47 vs -8.60±10.77, p=0.09, respectively). Tremor increased during hangover compared with low-dose alcohol (7.33±21.65 vs -10.31±10.73, p=0.03, respectively). A trend toward greater tremor during hangover occurred compared with high-dose alcohol (7.33±21.65 vs -4.12±17.17, p=0.08, respectively).

CONCLUSION

Alcohol-related decline in simulated surgical dexterity among senior vitreoretinal surgeons was dose-dependent. Dexterity improved the following morning but remained comparable to after low-dose alcohol ingestion. Tremor increased during hangover compared with same-day intoxication. Further studies are needed to investigate extrapolations of these data to a real surgical environment regarding patient safety and surgeon performance.

Phosphatidylethanol (B-PEth) and other direct and indirect biomarkers of alcohol consumption

When identifying, preventing and treating alcohol use disorder, a correct estimation of alcohol intake is essential. An objective marker is preferred as self-reported alcohol intake suffers from bias, and the use of alcohol biomarkers is increasing globally. An easy-to-use blood biomarker to correctly assess alcohol consumption is an invaluable asset in alcohol treatment strategies, as well as in alcohol research studies. The specific, cumulative, biomarker phosphatidylethanol, mirroring the past two weeks of consumption, has shown superiority over traditional biomarkers and is an attractive choice of proxy for alcohol intake.

Measurement uncertainty of ethyl alcohol concentration in the exhaled breath of drivers and determination of sobriety at the time of incident

The aim of the study was to determine the components of measurement uncertainty in the concentration of alcohol in exhaled breath and to determine the state of sobriety at the time of incident. Based on the literature review and the authors' experience in providing opinions for law enforcement and the judiciary, the influence of various factors on the final interpretation of sobriety state is described on the basis of measurement uncertainty of breath analyzers, uncertainty of retrospective and prospective calculations, and uncertainty related to the conversion of alcohol concentrations detected during breath and blood tests. The paper pays particular attention to interpreting the concentrations of ethanol in exhaled breath close to the legal limits of the state of sobriety and the state after alcohol use, or the state after alcohol use and the state of insobriety. Analyzing the results of an exhaled breath test concerning concentrations close to the values of 0.1 mg/dm3 and 0.25 mg/dm3, it is necessary to take into account the factors affecting the measurements obtained, including the measurement uncertainty of the determination of alcohol in exhaled breath, the processes of absorption, distribution and metabolism of ethyl alcohol, and the possibility of the presence of alcohol lingering in the oral cavity. The incorrect execution of measurements of the tested person's alcohol concentration is also a problematic issue. When determining sobriety state by means of retrospective and prospective calculations, it is important to remember that the uncertainty of the result is affected by a number of factors and depends, among other things, on the information provided by the suspect. Hence, the expert should draw conclusions particularly cautiously and any overestimation or underestimation of the components of uncertainty can lead to erroneous conclusions. Awareness of the uncertainties inherent in the results of a sobriety test or alcohol calculation allows for meaningful interpretation of test results and determination of the sobriety state of the person tested.

Mathematical modeling of the kinetics of a single intake of ethanol

The aim of the study is to construct a kinetic equation of zero-order ethanol elimination with first-order absorption, taking into account the presystemic metabolism of ethanol, with the possibility of determining the errors in estimating the parameters of the model, as well as the implementation of the model in the format of a computer program. Analytical mathematical modeling of the kinetics of a single oral intake of ethanol has been performed. A mathematical model of the kinetics of a single intake of ethanol with its zero-order elimination, absorption and first-order presystemic metabolism has been developed. A method is proposed for estimating the limiting absolute errors of the kinetic parameters of the constructed model based on the summation of the partial contributions of the initial physical quantities. The complex of the developed computational procedures is implemented in the format of the «Alcohol Calculator V 1.0» computer program. The conclusion is made about the expediency of using the developed information and computing technology in the forensic medical expert assessment of acute alcohol intoxication.

Mathematical modeling of the kinetics of a single intake of ethanol

The aim of the study is to construct a kinetic equation of zero-order ethanol elimination with first-order absorption, taking into account the presystemic metabolism of ethanol, with the possibility of determining the errors in estimating the parameters of the model, as well as the implementation of the model in the format of a computer program. Analytical mathematical modeling of the kinetics of a single oral intake of ethanol has been performed. A mathematical model of the kinetics of a single intake of ethanol with its zero-order elimination, absorption and first-order presystemic metabolism has been developed. A method is proposed for estimating the limiting absolute errors of the kinetic parameters of the constructed model based on the summation of the partial contributions of the initial physical quantities. The complex of the developed computational procedures is implemented in the format of the «Alcohol Calculator V 1.0» computer program. The conclusion is made about the expediency of using the developed information and computing technology in the forensic medical expert assessment of acute alcohol intoxication.

What does current science tell us about the accuracy, reliability, and completeness of intoxicated witnesses? A case example of the murder of a prime minister

Generally, the testimony of intoxicated witnesses has been considered relatively unreliable, but recent research has nuanced the knowledge base regarding these vulnerable witnesses.

Effects of alcohol hangover on attentional resources during a verbal memory/psychomotor tracking dual attention task

BACKGROUND

Alcohol hangover (AH) is associated with impaired attention and memory performance. However, whether this effect is related to reduced attentional resources remains unclear.

AIMS

A dual-attention paradigm was employed to assess the effects of AH on attentional resources, delayed memory recognition, and the interaction between attentional load and AH. Mental effort and perceived performance during AH and control conditions were also assessed.

METHODS

A seminaturalistic, crossover design was used. In total, 25 healthy social drinkers aged 18-35 years, visited the laboratory following a typical night out drinking (Hangover condition) and after alcohol abstinence (control) between 8:30 am and 12:30 pm, with conditions counterbalanced. Attentional load was manipulated via the presence (dual attention) or absence of psychomotor tracking during verbal memory encoding. Perceived mental effort and performance were measured using the NASA-TLX. Participants' recollected alcohol consumption was used to compute estimated blood alcohol level (eBAC).

RESULTS

Compared with the control visit, AH was associated with reduced recognition accuracy (particularly more false negatives), higher "tracking costs" (poorer accuracy) in the dual attention condition, increased ratings of "mental demand," "effort," and "frustration," and lower ratings of task performance. There was also a significant main effect of attentional load with poorer recognition accuracy and response time in the dual attention condition. There were no significant interaction effects between hangover and attentional load.

CONCLUSION

These findings suggest that reduced attentional resources contribute to the cognitive deficits associated with AH including impaired memory consolidation. They further suggest that while hungover, participants are aware of these deficits but are unable to compensate.

A MULTIFACTORIAL APPROACH FOR IMPROVING THE SURGICAL PERFORMANCE OF NOVICE VITREORETINAL SURGEONS

PURPOSE

To quantitatively analyze and compare the novice vitreoretinal surgeons' performance after various types of external exposures.

METHODS

This prospective, self-controlled, cross-sectional study included 15 vitreoretinal fellows with less than 2 years of experience. Surgical performance was assessed using the Eyesi simulator after each exposure: Day 1, placebo, 2.5, and 5 mg/kg caffeine; Day 2, placebo, 0.2, and 0.6 mg/kg propranolol; Day 3, baseline simulation, breathalyzer reading of 0.06% to 0.10% and 0.11% to 0.15% blood alcohol concentration; Day 4, baseline simulation, push-up sets with 50% and 85% repetition maximum; Day 5, 3-hour sleep deprivation. Eyesi-generated total scores were the main outcome measured (0-700, worst to best).

RESULTS

Performances worsened after increasing alcohol exposure based on the total score (χ2 = 7; degrees of freedom = 2; P = 0.03). Blood alcohol concentration 0.06% to 0.10% and 0.11% to 0.15% was associated with diminished performance compared with improvements after propranolol 0.6 and 0.2 mg/kg, respectively (∆1 = -22 vs. ∆2 = +13; P = 0.02; ∆1 = -43 vs. ∆2 = +23; P = 0.01). Propranolol 0.6 mg/kg was positively associated with the total score, compared with deterioration after 2.5 mg/kg caffeine (∆1 = +7 vs. ∆2 = -13; P = 0.03).

CONCLUSION

Surgical performance diminished dose dependently after alcohol. Caffeine 2.5 mg/kg was negatively associated with dexterity, and performance improved after 0.2 mg/kg propranolol. No changes occurred after short-term exercise or acute 3-hour sleep deprivation.

Time perception and alcohol use: A systematic review

Attentional, executive, and memory processes play a pivotal role in time perception. As acute or chronic alcohol consumption influences these processes, it should also modify time perception. We systematically reviewed and critically assessed all existing studies on time perception among alcohol drinkers, following the PICOS procedure and PRISMA guidelines. We selected 31 articles, distributed across four populations (i.e., alcohol intoxication, binge/heavy drinking, severe alcohol use disorder [SAUD], and Korsakoff syndrome). Several studies suggested the overestimation or underestimation of time during alcohol intoxication. No direct effect of binge/heavy drinking was observed on time perception, while studies on SAUD reported conflicting results. Participants with Korsakoff syndrome exhibited globally impaired time perception and marked deficits in associated cognitive abilities. This systematic review suggests that alcohol consumption affects time perception only when specific cognitive processes are depleted. However, due to the methodological limitations related to existing studies, no firm conclusion can be drawn. Guidelines and perspectives to advance the field are proposed.

Total body water is the preferred method to use in forensic blood-alcohol calculations rather than ethanol's volume of distribution

During the prosecution and defence of drink-driving cases, forensic practitioners are often required to engage in various blood-alcohol calculations, such as whether or not the statutory limit was exceeded (e.g. 80mg/100mL, 0.08g/100mL or 0.80g/L). For this purpose, most forensic scientists utilize the Widmark equation, or some modification thereof, to calculate a person's blood alcohol concentration (BAC) based on information about the amount of ethanol consumed and the pattern of drinking. This equation comes in two main forms; one of which incorporates the apparent volume of distribution of ethanol (V) and the other a person's total body water (TBW). In this study, we utilised two independent data sets, one involving the determination of V for ethanol in 173 men and 63 women, and the other TBW determined for 582 men and 884 women. Those subjects included in the TBW group represented various racial groups (Caucasians, African Americans, Hispanics, Asians and Puerto Ricans), with body mass index (BMI) ranging from 17 to 80kg/m². Both versions of the Widmark equation were evaluated in relation to their accuracy and precision in predicting TBW and/or V using the two most common anthropometric equations; those of Watson et al. and Forrest. Both anthropometric equations exhibited good accuracy (<4.3%) for the prediction of both TBW and V. However, the root mean square error was lower TBW was used for prediction (9.09-12.84%) rather than V (11.72-15.08%). Overall, this study has demonstrated (a) that blood-alcohol calculations are more reliable using TBW rather than V (b) that both equations (Watson et al. and Forrest) are applicable to ethnic groups other than Caucasians and (c) the Forrest equation predicts TBW in men and women with BMI from 17 to 35kg/m² and that the Watson et al. equation works for those with more extreme BMI; females (17-80kg/m²) and males (17-67kg/m²).

Prevalence of Hangover Resistance According to Two Methods for Calculating Estimated Blood Alcohol Concentration (eBAC)

Hangover resistance may be linked to an increased risk of continuing harmful drinking behaviours as well as involvement in potentially dangerous daily activities such as driving while hungover, mainly due to the absence of negative consequences (i.e., hangover symptoms) the day after alcohol consumption. The aim of this study was to examine the occurrence of claimed alcohol hangover resistance relative to estimated blood alcohol concentration (eBAC). A total of 1198 participants completed an online survey by answering questions regarding their demographics, alcohol consumption and occurrence of hangover. Two methods were used to calculate eBAC, one based on the modified Widmark Equation (N = 955) and the other from an equation averaging the total body water (TBW) estimates of Forrest, Watson, Seidl, Widmark and Ulrich (males only) (N = 942). The percentage of participants who claimed to be hangover resistant decreased rapidly with increasing eBAC and only a small number of hangover resistant drinkers remained at higher eBACs. Comparisons of the eBACs calculated by the two methods revealed significantly higher BACs when using the modified Widmark equation. These findings suggest that additional research for eBAC calculations is needed to improve accuracy and comprehensiveness of these equations for future alcohol hangover research.

The impact of total body water on breath alcohol calculations

Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h⁻¹) and women (0.074 ± 0.017 mg/L h⁻¹). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).

Alcohol Hangover and Multitasking: Effects on Mood, Cognitive Performance, Stress Reactivity, and Perceived Effort

The aim of this study was to examine the effects of hangover on mood, multitasking ability, and psychological stress reactivity to cognitive demand. Using a crossover design and semi-naturalistic methodology, 25 participants attended the laboratory in the morning following a night of (i) alcohol abstinence and (ii) alcohol self-administration during a typical night out (with order counterbalanced across participants). They completed a four-module multitasking framework (MTF, a widely used laboratory stressor) and a battery of questionnaires assessing mood, hangover symptom severity, and previous night’s sleep. The effects of the MTF on mood and perceived workload were also assessed. Participants in the hangover condition reported significantly lower alertness and contentment coupled with a higher mental fatigue and anxiety. Multitasking ability was also significantly impaired in the hangover condition. Completion of the cognitive stressor increased reported levels of mental demand, effort, and frustration, and decreased perceived level of performance. MTF completion did not differentially affect mood. Lastly, participants rated their sleep as significantly worse during the night prior to the hangover compared with the control condition. These findings confirm the negative cognitive and mood effects of hangover on mood. They also demonstrate that hangover is associated with greater perceived effort during task performance.

Pain Catastrophising Predicts Alcohol Hangover Severity and Symptoms

Alcohol hangover is a cause of considerable social and economic burden. Identification of predictors of alcohol hangover severity have the potential to contribute to reductions in costs associated with both absenteeism/presenteeism and health care. Pain catastrophising (PC) is the tendency to ruminate and describe a pain experience in more exaggerated terms. The current study examines the possibility that this cognitive coping strategy may influence experience of alcohol hangover. The aims of the current study were to (1) examine the relationship between hangover severity and PC, (2) explore and identify discreet factors within the Acute Hangover Scale (AHS) and (3) explore whether independent factors/dimensions of acute hangover are differentially predicted by PC. A retrospective survey (n = 86) was conducted in which participants completed the Acute Hangover Scale (AHS); the Pain Catastrophising Scale (PCS); a questionnaire pertaining to the amount of alcohol consumed; and a demographic information questionnaire. Regression analyses showed a significant relationship between PC and hangover severity scores and demonstrated that PC was, in fact, a stronger predictor of perceived hangover severity than estimated peak blood alcohol concentrations (eBACs). Factor analysis of the AHS scale, resulted in the identification of two distinct symptom dimensions; ‘Headache and thirst’, and ‘Gastric and cardiovascular’ symptoms. Regression analyses showed that both eBAC and PCS score were significantly associated with ‘Headache and thirst’. However, only PCS score was associated with ‘Gastric and cardiovascular’ symptoms. These novel findings implicate a role for cognitive coping strategies in self-reports of alcohol hangover severity, and may have implications for understanding behavioural response to hangover, as well as suggesting that hangover and PC may be important factors mediating the motivation to drink and/or abuse alcohol, with potential implications in addiction research. Furthermore, these findings suggest that distinct alcohol hangover symptoms may be associated with different mechanisms underlying the experience of alcohol hangover.

Evidence based survey of the distribution volume of ethanol: Comparison of empirically determined values with anthropometric measures

The Widmark equation is commonly used when blood alcohol calculations are required in forensic and legal medicine, such as in road-traffic cases and alcohol-related deaths. An important biological variable in this connection is the volume of distribution (V_d) of ethanol, which is commonly referred to as the rho-factor. Although a person's V_d can be determined empirically through controlled drinking experiments, this approach is not very practical in reality. For this reason, a number of anthropometric equations have been developed that utilize sex, age, height and weight to estimate the person's total body water (TBW) and hence V_d of ethanol. To date, there are not any studies that compare V_d derived from anthropometric data with robust values measured empirically. From the literature we compiled information about the V_d of ethanol from drinking studies with 173 Caucasian males and 63 Caucasian females from Western Europe. These empirically derived values of V_d were then compared with estimates derived from various anthropometric equations. In males the Watson, Watson and Batt regression equation involving age, height and weight gave the most accurate results (bias was 0.00L/kg) and 95% range ±0.13L/kg. The equation derived by Forrest, which took into consideration a person's body mass index (BMI), gave the best estimates of V_d for females; mean bias -0.01L/kg and range ±0.15L/kg.

The influence of alcohol content variation in UK packaged beers on the uncertainty of calculations using the Widmark equation

It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v - 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12 months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations.

Evaluation of breath alcohol analysers by comparison of breath and blood alcohol concentrations

The main goal of this study was to determine the reliability of hand-held breath alcohol analysers currently approved for roadside screening of traffic offenders. The first part of the study included a retrospective data analysis of 714 offence records collected in 2011. Blood alcohol concentrations (BAC) obtained from the offenders 0-303 min after the police had screened them for breath alcohol concentration (BrAC) were back-calculated (cBAC) to assess the accuracy of breathalyser screening. All participants were in the alcohol elimination phase, and our analyses did not reveal any significant differences between cBAC and BrAC. To verify our findings, we performed a controlled drinking study that involved 63 healthy volunteers who consumed alcoholic beverages to simulate real drinking conditions. Immediately after alcohol consumption, BrAC was determined with a Dräger breath alcohol analyser model 6810, and 29 participants gave blood and urine sample for concomitant BAC analysis one hour later. BAC and urine alcohol concentrations were determined with headspace gas chromatography. Again, we found no significant differences between BrAC and BAC. These results confirmed the high reliability of breath alcohol analysers for measuring BrAC as long as police officers perform the measurements according to the manufacturer’s instructions.

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.

Hangover resistance in a Canadian University student population

Background

Resistance to alcohol hangover may be a risk factor for alcohol use disorder. Previous research to establish the prevalence of hangover resistance in a drinking population has either not used comparable intoxication levels or has considered hangover resistance over a limited time frame. The purpose of this study was to examine the prevalence of lifetime hangover negative (LHN) drinkers across comparable eBAC values ranging from 0 to 500 mg/dl.

Methods

Students at an eastern Canadian university were surveyed about their heaviest drinking episode in the past month and indicated whether they had ever experienced a hangover in their lifetime (LHN) and, if they had, the hangover severity they experienced the next day. eBACs were calculated and the percentage of LHN drinkers was computed at each 10 mg/dl eBAC increment from 0 to 500 mg/dl.

Results

Most LHN drinkers (58% female, 71% male) had an eBAC on their heaviest drinking occasion below 80 mg/dl. Above eBACs of 80 mg/dl, 5.8% of female and 5.1% of male drinkers were lifetime hangover negative.

Conclusions

The results suggest that only a small percentage of heavy drinkers lay claim to being lifetime hangover negative.

•

The estimated BAC of more than half of male and female lifetime hangover negative drinkers was below 80 mg%.

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Approximately 5% of drinkers registering estimated BAC’s beyond 80 mg% claim to be lifetime hangover negative.

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Biological and psychological hypotheses are proposed to explain why heavy drinkers may be lifetime hangover negative.

Does familial risk for alcohol use disorder predict alcohol hangover?

AIMS

Positive family history of alcohol use disorder (FHP), a variable associated with propensity for alcohol use disorder (AUD), has been linked with elevated hangover frequency and severity, after controlling for alcohol use. This implies that hangover experiences may be related to AUD. However, inadequate control of alcohol consumption levels, low alcohol dose and testing for hangover during the intoxication phase detract from these findings. Here, we present further data pertinent to understanding the relationship between family history and alcohol hangover.

METHODS

Study 1 compared past year hangover frequency in a survey of 24 FHP and 118 family history negative (FHN) individuals. Study 2 applied a quasi-experimental naturalistic approach assessing concurrent hangover severity in 17 FHP and 32 FHN individuals the morning after drinking alcohol. Both studies applied statistical control for alcohol consumption levels.

RESULTS

In Study 1, both FHP status and estimated blood alcohol concentration on the heaviest drinking evening of the past month predicted the frequency of hangover symptoms experienced over the previous 12 months. In Study 2, estimated blood alcohol concentration the previous evening predicted hangover severity but FHP status did not.

CONCLUSIONS

FHP, indicating familial risk for AUD, was not associated with concurrent hangover severity but was associated with increased estimates of hangover frequency the previous year.

The effect of alcohol hangover on choice response time

The effect of alcohol hangover on cognitive processing has received little attention. We explored the effect of alcohol hangover on choice response time (RT), a dominant dependent variable (DV) in cognitive research. Prior research of the effect of hangover on RT has produced mixed findings; all studies reviewed relied exclusively on estimates of central tendency (e.g. mean RT), which has limited information value. Here we present novel analytical methods by going beyond mean RT analysis. Specifically, we examined performance in hangover conditions (n=31) across the whole RT distribution by fitting ex-Gaussian models to participant data, providing a formal description of the RT distribution. This analysis showed detriments to performance under hangover conditions at the slower end of the RT distribution and increased RT variance under hangover conditions. We also fitted an explicit mathematical process model of choice RT - the diffusion model - which estimates parameters reflecting psychologically-meaningful processes underlying choice RT. This analysis showed that hangover reduced information processing efficiency during response selection, and increased response caution; changes in these parameters reflect hangover affecting core decisional-components of RT performance. The implications of the data as well as the methods used for hangover research are discussed.

Best-practices approach to determination of blood alcohol concentration (BAC) at specific time points: Combination of ante-mortem alcohol pharmacokinetic modeling and post-mortem alcohol generation and transport considerations

Alcohol concentrations in biological matrices offer information regarding an individual's intoxication level at a given time. In forensic cases, the alcohol concentration in the blood (BAC) at the time of death is sometimes used interchangeably with the BAC measured post-mortem, without consideration for alcohol concentration changes in the body after death. However, post-mortem factors must be taken into account for accurate forensic determination of BAC prior to death to avoid incorrect conclusions. The main objective of this work was to describe best practices for relating ante-mortem and post-mortem alcohol concentrations, using a combination of modeling, empirical data and other qualitative considerations. The Widmark modeling approach is a best practices method for superimposing multiple alcohol doses ingested at various times with alcohol elimination rate adjustments based on individual body factors. We combined the selected ante-mortem model with a suggestion for an approach used to roughly estimate changes in BAC post-mortem, and then analyzed the available data on post-mortem alcohol production in human bodies and potential markers for alcohol production through decomposition and putrefaction. Hypothetical cases provide best practice approaches as an example for determining alcohol concentration in biological matrices ante-mortem, as well as potential issues encountered with quantitative post-mortem approaches. This study provides information for standardizing BAC determination in forensic toxicology, while minimizing real world case uncertainties.

Intra-individual and inter-individual variation in breath alcohol pharmacokinetics: Variation over three visits

Eleven male and 7 female student subjects underwent serial Breath Alcohol Concentration (BrAC) measurements after being given alcohol as 13% white wine (5.7 ml/kg for males and 4.7 ml/kg for females) in a fasting state on three separate occasions. BrAC versus time curves were constructed for each subject and the values of peak BrAC (Cmax), theoretical BrAC extrapolated at zero time (Co), time taken to reach peak (Tmax) and rate of elimination (ß) from breath were recorded directly from the curves. Average Intra-individual variation for each individual between the 3 visits (for males and females, respectively) was 5.6% and 8% for Co, 12% and 13% for Cmax, 42% and 37% for Tmax and 11% and 13% for ß. Inter-individual variation (for males and females) was 7.5% and 13% for Co, 16% and 15% for Cmax, 43% and 46% for Tmax and 21% and 15% for ß. Average elimination rates in males (5.3 μg/100 ml breath/h, range 4-7.7) and females (5.6 μg/100 ml breath/h, range 4-7) were not significantly different. Widmark factors calculated by various established mathematical methods were 0.71-0.81 in males and 0.59-0.68 in females, higher than the originally quoted mean experimental levels.

The estimation of blood alcohol concentration : Widmark revisited

Expert witnesses and others involved in toxicology are frequently asked to perform retrograde extrapolation of blood alcohol concentration (BAC) or to estimate BAC based on a proposed drinking scenario. Although many individuals are reluctant to perform these calculations and some jurisdictions expressly prohibit them, a significant number of practitioners routinely estimate BAC based on this type of calculation, using as a basis the fundamental work of Widmark. Although improvements to the Widmark formula and other data pertaining to the pharmacology of alcohol have been published, these improvements are frequently ignored when estimating BAC. This article summarizes five published models for the estimation of BAC and proposes a sixth model that incorporates recent data on the rate of absorption of alcohol from the GI tract into the existing five models. The five improved models can be computerized and used to construct comparative snapshots of the BACs calculated by the different algorithms. This will allow practitioners to provide a more balanced picture of the variability in BAC calculations.

Differences between the measured blood ethanol concentration and the estimated concentration by Widmark's equation in elderly persons

BACKGROUND

The Widmark's equation (C [BAC]=A/p×r) is the most commonly used formula in legal medicine to estimate the blood alcohol concentration (BAC) from the amount of ingested ethanol and vice versa. Within a drinking experiment with a target BAC of 1.2 g/kg, a 75-year-old participant reached a maximum BAC of 1.83 g/kg and showed signs of severe ethanol intoxication, while the other nine subjects (age: 19-31 years) had BACs close to the target BAC. This incident brought up the question, if the Widmark's equation is an appropriate tool for aged persons.

METHODS

A drinking experiment with 50 elderly voluntary test persons (22 males, 28 females, mean age and range [males]: 69.7 years, 60-84 years, mean age and range [females]: 68.5 years, 61-78 years) was performed. The amount of ethanol leading to a BAC of 0.6 g/kg was estimated individually using the Widmark's equation (used Widmark factors: 0.7 for males, 0.6 for females). After drinking, the blood ethanol concentrations were measured using headspace gas chromatography/flame ionization detection.

RESULTS

The measured maximum BACs of the elderly participants were significantly higher (α=0.01) than the target BAC (mean maximum BAC and range: 0.627 g/kg, 0.3-0.81 g/kg, for males: 0.616 g/kg, 0.32-0.78 g/kg, for females: 0.635 g/kg, 0.3-0.81). The calculated Widmark factors showed a high coefficient of variation (for males: 0.7±0.138 [0.55-1.2, CV: 19.7%], for females 0.59±0.119 [0.46-1.08, CV: 20.2%]).

CONCLUSION

The results demonstrate that BAC calculations by Widmark's equation in elderly individuals may be complicated by a high variation of Widmark factors. There is a tendency to an elevation of the actual BAC with increasing age.

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.

Decreased effective connectivity in the visuomotor system after alcohol consumption

Functional magnetic resonance imaging (fMRI) allows observing cerebral activity not only in separated cortical regions but also in functionally coupled cortical networks. Although moderate doses of ethanol slowdown the neurovascular coupling, the functions of the primary sensorimotor and the visual system remain intact. Yet little is known about how more complex interactions between cortical regions are affected even at moderate doses of alcohol. Therefore the method of psychophysiological interaction (PPI) was applied to analyze ethanol-induced effects on the effective connectivity in the visuomotor system. Fourteen healthy social drinkers with no personal history of neurological disorders or substance abuse were examined. In a test/re-test design they served as their own controls by participating in both the sober and the ethanol condition. All participants were scanned in a 3 T MR scanner before and after ingestion of a body-weight-dependent amount of ethanol calculated to achieve a blood alcohol concentration of 1.0‰. PPIs were calculated for the primary visual cortex, the supplementary motor area, and the left and right primary motor cortex using the statistical software package SPM. The PPI analysis showed selective disturbance of the effective connectivity between different cortical areas. The regression analysis revealed the influence of the supplementary motor area on connected regions like the primary motor cortex to be decreased yet preserved. However, the connection between the primary visual cortex and the posterior parietal cortex was more severely impaired by the influence of ethanol, leading to an uncoupled regression between these regions. The decreased effective connectivity in the visuomotor system suggests that complex tasks requiring interaction or synchronization between different brain areas are affected even at moderate levels of alcohol. This finding may have important consequences for determining which components of demanding tasks such as driving a car might be compromised earlier than the functions of the main cortical motor and visual areas.

A case of a distinct difference between the measured blood ethanol concentration and the concentration estimated by Widmark's equation

In the last century, several mathematical models have been developed to calculate blood ethanol concentrations (BAC) from the amount of ingested ethanol and vice versa. The most common one in the field of forensic sciences is Widmark's equation. A drinking experiment with 10 voluntary test persons was performed with a target BAC of 1.2 g/kg estimated using Widmark's equation as well as Watson's factor. The ethanol concentrations in the blood were measured using headspace gas chromatography/flame ionization and additionally with an alcohol dehydrogenase (ADH)-based method. In a healthy 75-year-old man a distinct discrepancy between the intended and the determined blood ethanol concentration was observed. A blood ethanol concentration of 1.83 g/kg was measured and the man showed signs of intoxication. A possible explanation for the discrepancy is a reduction of the total body water content in older people. The incident showed that caution is advised when using the different mathematical models in aged people. When estimating ethanol concentrations, caution is recommended with calculated results due to potential discrepancies between mathematical models and biological systems.

Ethanol modulates the neurovascular coupling

Despite some evidence of the underlying molecular mechanisms the neuronal basis of ethanol-induced effects on the neurovascular coupling that forms the BOLD (blood oxygenation level dependent) signal is poorly understood. In a recent fMRI (functional magnetic resonance imaging) study monitoring ethanol-induced changes of the BOLD signal a reduction of the amplitude and a prolongation of the BOLD signal were observed. However, the BOLD signal is assumed to consist of a complex superposition of different underlying signals. To gain insight how ethanol influences stimulus efficacy, oxygen extraction, transit time and vessel-related parameters the fMRI time series from the sensori-motor and the visual cortex were analyzed using the balloon model. The results show a region-dependent decrease of the stimulus efficacy to trigger a post-stimulus neurovascular response as well as a prolongation of the transit time through the venous compartment. Oxygen extraction, feedback mechanisms and other vessel-related parameters were not affected. The results may be interpreted as follows: the overall mechanisms of the neurovascular coupling are still acting well at the moderate ethanol level of about 0.8‰ (in particular the vessel-related parts), but the potency to evoke a neurovascular response is already compromised most obviously in the supplementary motor area responsible for complex synchronizing and planning processes.

An overview of alcohol testing and interpretation in the 21st century

Ethanol analysis is the most commonly carried out drug testing in a forensic toxicology laboratory. Determination of blood alcohol concentration (BAC) is needed in a multitude of situations, including in postmortem analysis, driving under the influence (DUI) and drug-facilitated sexual assault (DFSA) cases, workplace drug monitoring, and probation investigations. These analyses are carried out by direct measurement of ethanol concentrations as well as of metabolic by-products, such as ethyl glucuronide (EtG) and ethyl sulfate (EtS). This review article will discuss pharmacokinetics, including absorption, distribution, and elimination of ethanol, methods for the detection of ethanol, the effect of ethanol on human performance, the role of alcohol in injuries and fatalities, and information regarding the interactions that may occur between alcohol and other drugs. Finally, an explanation will be given on how to interpret alcohol levels as well as the extrapolation and calculation of blood alcohol levels at times prior to sample collection.

Alcohol induced region-dependent alterations of hemodynamic response: implications for the statistical interpretation of pharmacological fMRI studies

Worldwide, ethanol abuse causes thousands of fatal accidents annually as well as innumerable social dysfunctions and severe medical disorders. Yet, few studies have used the blood oxygenation level dependent functional magnetic resonance imaging method (BOLD fMRI) to map how alcohol alters brain functions, as fMRI relies on neurovascular coupling, which may change due to the vasoactive properties of alcohol. We monitored the hemodynamic response function (HRF) with a high temporal resolution. In both motor cortices and the visual cortex, alcohol prolonged the time course of the HRF, indicating an overall slow-down of neurovascular coupling rather than an isolated reduction in neuronal activity. However, in the supplementary motor area, alcohol-induced changes to the HRF suggest a reduced neuronal activation. This may explain why initiating and coordinating complex movements, including speech production, are often impaired earlier than executing basic motor patterns. Furthermore, the present study revealed a potential pitfall associated with the statistical interpretation of pharmacological fMRI studies based on the general linear model: if the functional form of the HRF is changed between the conditions data may be erroneously interpreted as increased or decreased neuronal activation. Thus, our study not only presents an additional key to how alcohol affects the network of brain functions but also implies that potential changes to neurovascular coupling have to be taken into account when interpreting BOLD fMRI. Therefore, measuring individual drug-induced HRF changes is recommended for pharmacological fMRI.

Alcohol influences the use of decisional support

AIM

Excess consumption of alcohol leads to impaired cognition and decision making; hence, alcohol-containing products and advertising contain warning messages about the adverse effects of excess drinking. However, there is a need to understand how alcohol influences the processing of advisory messages.

METHOD

The current study used a computerised gambling simulation and investigated whether intoxication would affect the use of a decision aid. Using a double-blind repeated measures design, 16 adult males (aged 18-29) completed the Alcohol Use Disorders Identification Test and the South Oaks Gambling Screen and played a computer blackjack program on two separate occasions, under differing doses of alcohol. On certain conditions, the computerised decision aid gave advice to participants as to whether the odds were in their favour.

RESULTS

Participants were found to take longer to respond to the decision aid under higher risk conditions when they were losing.

CONCLUSION

Alcohol intoxication may lead to problems evaluating information pertaining to risk, and this has implications for the use of other decision aids designed to assist intoxicated individuals. The problems processing warning information were consistent with alcohol induced 'myopia' where intoxicated individuals had problems processing less salient cues.

Alcohol study on blood concentration estimation: reliability and applicability of Widmark formula on Chinese male population

Widmark formula suggests estimating blood alcohol concentration level (BAC) on a given amount of alcohol administrated with knowledge of subject's body weight and sex. The idea has been referenced extensively in forensic science with application in drink driving prosecution. A sample of Chinese subjects was collected in the drinking experiment, and in this study we mainly focus on the verification of the validity of Widmark formula on Chinese male population. A promising result is obtained where the extrapolated BAC measurement is directly proportional to the amount of alcohol administrated, and inversely to the subject's body weight. The results noted in the general linear model is further supported by the nonlinear regression analysis and a concordant argument reaches by deploying the concept to the BAC level attained at peak.

The relationship between alcohol elimination rate and increasing blood alcohol concentration—Calculated from two consecutive blood specimens

In the period 1991-2005, a blood-alcohol concentration (BAC) analysis was carried out at the Institute of forensic medicine in Novi Sad including 2023 two consecutive blood specimens using the Headspace Gas Chromatography method. Cases with no alcohol concentration values, as well as cases where blood samples were taken within 1 h after the criminal act, were not taken into consideration. Following this rule, 1198 cases were considered in this study and all samples were grouped in 29 ranges of BAC1 of delta(BAC) = 0.1 g/kg, starting from 0.1-0.19 g/kg to 2.9-2.99 g/kg of absolute alcohol. Gathered results and elimination curve differ from the zero-order model of elimination proposed by Widmark and point to an elimination process similar to a well-known Michaelis-Menten elimination kinetics model and its variants. Results reported in this study show dependence of alcohol elimination rate (beta-slope) and BAC value. The analysis of beta60-slope versus BAC shows that a correlation between beta60 (y) and BAC (x) has a logarithmic trend line. The value of alcohol elimination rate shows a slight increment with increase of BAC alcohol, with the mean value of beta60 = 0.221 +/- 0.075 g/kg. Differences in values of beta60 among consecutive intervals of delta(BAC) = 0.1 g/kg are not significant (p>0.05). When obtained samples were grouped into ranges of 0.5 g/kg each in these intervals beta60 had the following values by range: 0.1-0.49 g/kg = 0.139 g/kg +/- 0.035; 0.5-0.99 g/kg = 0.184 g/kg +/- 0.043; 1-1.49 g/kg = 0.213 g/kg +/- 0.052; 1.5-1.99 g/kg = 0.239 g/kg +/- 0.058; 2-2.49 g/kg = 0.265 g/kg +/- 0.073; 2.5-2.99 g/kg = 0.306 g/kg +/- 0.096. Differences in values of beta slope among consecutive intervals of delta(BAC) = 0.5 g/kg are significant (p<0.01). The elimination curve in the BAC interval 0.5-2.5 g/kg has a linear trend, while beta-slope (y)/BAC (x) correlation is given as beta60 = 0.15 g/kg + (0.05 g/kg x BAC). Retrograde calculation of the blood alcohol concentration in tempore criminis (BAC(tc)) based on the determined alcohol concentration in the blood specimen (BAC(t)) shows a statistically significant difference between BAC(tc) calculated using a standard zero-order model versus corrected methodology. The higher the BAC(t) and the longer the calculation time, the greater and statistically more significant (p<0.01) is the difference between the calculated values of BAC(tc).