Breath Alcohol Concentration Levels Research Articles

Bicycling during alcohol intoxication

The number of bicycling fatalities was 19 450 between 2010 and 2018 in Europe. The number of bicyclists killed when intoxicated by alcohol is harder to establish given the lack of reliable data. In Sweden, drunk bicycling is socially acceptable and legal (unless reckless). This experiment aimed to investigate how alcohol intoxication affect bicycling stability performance, executive functions, and self-rated ability. The experiment was completed on a wide treadmill that allowed control of several influencing factors such as speed and physical effort. Intoxicated and sober participants bicycled on the treadmill for five 10 minute sessions. Alcohol as administered incrementally to reach a target breath alcohol concentration level of 0.8‰. Stability decreased with intoxication; especially roll rate measurements were identified as being adequate indicators of bicycling instability. Executive function was negatively affected, and ability ratings decreased due to intoxication. The intoxicated participants were aware of their reduced ability to bicycle in a safe manner on a group level but not on an individual level. However, this insight does not affect their intention to bicycle intoxicated.

Alcohol impairs driver attention and prevents compensatory strategies

While the negative effects of alcohol on driving performance are undisputed, it is unclear how driver attention, eye movements and visual information sampling are affected by alcohol consumption. A simulator study with 35 participants was conducted to investigate whether and how a driver’s level of attention is related to self-paced non-driving related task (NDRT)-engagement and tactical aspects of undesirable driver behaviour under increasing levels of breath alcohol concentration (BrAC) up to 1.0 ‰. Increasing BrAC levels lead to more frequent speeding, short time headways and weaving, and higher NDRT engagement. Instantaneous distraction events become more frequent, with more and longer glances to the NDRT, and a general decline in visual attention to the forward roadway. With alcohol, the compensatory behaviour that is typically seen when drivers engage in NDRTs did not appear. These findings support the theory that alcohol reduces the ability to shift attention between multiple tasks. To conclude, the independent reduction in safety margins in combination with impaired attention and an increased willingness to engage in NDRTs is likely the reason behind increased crash risk when driving under the influence of alcohol.

Assessing alcohol use in situ: Correlates of self-report vs. objective alcohol consumption

Associations between self-report and objective measurement of young adult alcohol use are weakened by excessive consumption levels; therefore, associations between correlates of alcohol use and consumption likely also differ by alcohol measurement. This study examined the extent to which correlates of heavy drinking measured via self-report are also indicators of heavy drinking measured objectively. Data were collected from 164 bar patrons (54% male; 73% White, 12% Black, 15% Other; 15% Hispanic) as they exited the bar. Participants completed an intercept survey including self-reported measures of drinking, demographics, and social-environmental factors. A breath alcohol concentration (BrAC) reading was also obtained using a handheld breathalyzer device. Correlations between two self-reported outcomes, number of drinks consumed prior to and at the bar, and BrAC were significant among those in the lowest quartile of BrAC readings, but largely non-significant at moderate and high BrAC levels. Intention to get drunk that night was a robust predictor of alcohol consumption across self-reported outcomes and BrAC. Social factors (presence of drinking peers, witnessing drunk others) were predictive of self-reported alcohol use but not BrAC. AUDIT-C score was the only additional alcohol behavior predictive of objectively measured alcohol use. Self-reported outcomes and BrAC, as well as their association with key correlates, diverge at high levels of intoxication, when preventive intervention is most needed. Implications for further research and alcohol prevention practice are discussed.

A parallel test of the SCRAM-CAM transdermal monitors ensuring reliability.

Previous studies validating the transdermal alcohol concentration (TAC) as measured by the Secure Continuous Remote Alcohol Monitors Continuous Alcohol Monitoring (SCRAM-CAM) have tested the monitor against self-reports or breath alcohol concentration (BrAC). This study aims to provide further evidence of the reliability of the SCRAM-CAM testing two monitors in parallel. Participants (N=21) received four standard drinks in a laboratory session while wearing SCRAM-CAMs simultaneously on their left and right ankles. The SCRAM-CAMs sampled TAC every 30 min and participants were monitored for at least 2-3h after their BrAC levels reached zero. Weight and height measures were taken to calculate body mass index (BMI). There was a positive correlation between the TAC measurements from the left and right SCRAM-CAM (r=0.718), a cross-correlation model revealed that this correlation was not significantly different for sex or BMI. Area under the TAC curve (AUC) and peak TAC values as measured by the left and right SCRAM-CAM also show positive correlations (r=0.554 and r=0.579, respectively). Cross-correlation models show a significant effect of BMI on the relationship between left and right peak TAC values, which may be due to outlier effects. No further effects were significant for on both peak and AUC values. Results show that TAC measured by SCRAM-CAMs worn on the left and right showed a good correlation, with correlations between AUC and peak TAC values considered to be fair. TAC monitors show promise for use in research settings; however, work is needed testing the reliability of TAC as measured by two TAC monitors.

Machine learning prediction of blood alcohol concentration: a digital signature of smart-breathalyzer behavior

Excess alcohol use is an important determinant of death and disability. Machine learning (ML)-driven interventions leveraging smart-breathalyzer data may help reduce these harms. We developed a digital phenotype of long-term smart-breathalyzer behavior to predict individuals’ breath alcohol concentration (BrAC) levels trained on data from a smart breathalyzer. We analyzed roughly one million datapoints from 33,452 users of a commercial smart-breathalyzer device, collected between 2013 and 2017. For validation, we analyzed the associations between state-level observed smart-breathalyzer BrAC levels and impaired-driving motor vehicle death rates. Behavioral, geolocation-based, and time-series-derived features were fed to an ML algorithm using training (70% of the cohort), development (10% of the cohort), and test (20% of the cohort) sets to predict the likelihood of a BrAC exceeding the legal driving limit (0.08 g/dL). States with higher average BrAC levels had significantly higher alcohol-related driving death rates, adjusted for the number of users per state B (SE) = 91.38 (15.16), p < 0.01. In the independent test set, the ML algorithm predicted the likelihood of a given user-initiated BrAC sample exceeding BrAC ≥ 0.08 g/dL, with an area under the curve (AUC) of 85%. Highly predictive features included users’ prior BrAC trends, subjective estimation of their BrAC (or AUC = 82% without the self-estimate), engagement and self-monitoring, time since the last measure, and hour of the day. In conclusion, an ML algorithm successfully quantified a digital phenotype of behavior, predicting naturalistic BrAC levels exceeding 0.08 g/dL (a threshold associated with alcohol-related harm) with good discrimination capability. This result establishes a foundation for future research on precision behavioral medicine digital health interventions using smart breathalyzers and passive monitoring approaches.

Personal Assessment of Ability to Drive Under the Influence of Alcohol vs. Objective Measurement.

Alcohol intoxication often affects patient management in the emergency department. This study evaluates participants' subjective sense of impairment using ability to drive as a reference compared with measured breath alcohol concentrations (BrAC) and evaluate whether there is a gender difference. In this prospective study, 55 volunteers consumed one beer and estimated their BrAC and their ability to drive. BrAC was measured objectively and participants were blinded to the value until they reached a BrAC of 0.1 g/dL. Then they stopped drinking and estimated their BrAC and ability to drive every 30 min until objective BrAC reached 0.08 g/dL. As BrAC increased, the association between estimated and perceived ability to drive was significantly different (p < 0.0001). At BrAC levels > 0.08 g/dL, 20.3% affirmed the ability to drive. At BrAC levels < 0.08 g/dL, 35.5% denied ability to drive. As BrAC decreased, the association between estimated and actual ability to drive was significantly different (p = 0.001). At BrAC values > 0.08 g/dL, 59.7% affirmed the ability to drive. At BrAC < 0.08 g/dL, 49.1% denied ability to drive. As BrAC increased, the correlations for men and women were strong and statistically significant (r = 0.80, p < 0.0001 and r = 0.79, p < 0.0001, respectively). As men's and women's BrAC decreased, the women's correlation was higher (r = 0.061 and r = 0.74, respectively; p < 0.0001). Both genders can estimate their impaired ability to drive while drinking, but women are better at assessing their capacity to drive after drinking cessation.

Effects of a multi-component alcohol prevention intervention at sporting events: a quasi-experimental control group study.

Alcohol intoxication among spectators and related problems are common at sporting events. This study estimated the impact a multi-component community-based alcohol prevention intervention, implemented at Swedish Premier Football (soccer) League matches, had on intoxication levels among spectators and refusal rates of alcohol service to, and arena entry of, obviously intoxicated spectators. A quasi-experimental controlled study using a repeated cross-sectional design. Spectators and sport arenas in Stockholm and Gothenburg, Sweden. The intervention was implemented in Stockholm and consisted of community mobilisation and collaboration, training of staff and improved enforcement and policy work. Gothenburg was the comparison area and received usual care. Primary outcomes were spectators' mean breath alcohol concentration (BrAC), proportion of spectators with high intoxication levels, (defined as BrAC ≥0.1%), overserving at licensed premises inside arenas and refused arena entry of obviously intoxicated spectators. Baseline data were collected during 2015 and follow-up during 2016 and 2017. BrAC assessments (n=10 188), arena entry attempts (n=201) and alcohol purchase attempts at premises inside arenas (n=495) were collected. There was evidence that the refusal rates of alcohol purchase at premises inside arenas improved differently between study areas and over time (adjusted odds ratio [aOR]=0.28, 95% CI=0.07, 1.06, P=0.060, Bayes factor [BF]=8.60). In both study areas, the arena entry refusal rates improved over time (aOR=5.87, 95% CI=1.16, 29.83, P=0.033, BF=17.7), but evidence that the rates improved differently between study areas and over time was equivocal (aOR=0.57, 95% CI=0.09, 3.56, P=0.543, BF=1.2). Mean BrAC levels decreased over time in both study areas (β=-0.032, 95% CI=-0.050, -0.015, P<0.001), and differently (β=0.104, 95% CI=0.061, 0.146, P<0.001), but evidence for an interaction effect was equivocal (β=-0.002, 95% CI=-0.022, 0.018, P=0.868, BF=1.0). Evidence was equivocal regarding whether the proportion of spectators with high intoxication levels decreased differently between study areas and over time (aOR=1.17, 95% CI=0.91, 1.50, P=0.220, BF=2.2). A multi-component community-based alcohol prevention intervention at sporting events may have increased staff intervention toward obviously intoxicated spectators. It was not clear whether this translated into a reduction in intoxication, which can be explained by improvements in the comparison area.

Effects of stomach content on the breath alcohol concentration-transdermal alcohol concentration relationship.

Wearable devices that obtain transdermal alcohol concentration (TAC) could become valuable research tools for monitoring alcohol consumption levels in naturalistic environments if the TAC they produce could be converted into quantitatively-meaningful estimates of breath alcohol concentration (eBrAC). Our team has developed mathematical models to produce eBrAC from TAC, but it is not yet clear how a variety of factors affect the accuracy of the models. Stomach content is one factor that is known to affect breath alcohol concentration (BrAC), but its effect on the BrAC-TAC relationship has not yet been studied. We examine the BrAC-TAC relationship by having two investigators participate in four laboratory drinking sessions with varied stomach content conditions: (i) no meal, (ii) half and (iii) full meal before drinking, and (iv) full meal after drinking. BrAC and TAC were obtained every 10min over the BrAC curve. Eating before drinking lowered BrAC and TAC levels, with greater variability in TAC across person-device pairings, but the BrAC-TAC relationship was not consistently altered by stomach content. The mathematical model calibration parameters, fit indices, and eBrAC curves and summary score outputs did not consistently vary based on stomach content, indicating that our models were able to produce eBrAC from TAC with similar accuracy despite variations in the shape and magnitude of the BrAC curves under different conditions. This study represents the first examination of how stomach content affects our ability to model estimates of BrAC from TAC and indicates it is not a major factor.

Assessing the utility of a virtual-reality neuropsychological test battery, 'CONVIRT', in detecting alcohol-induced cognitive impairment.

New technologies such as virtual reality (VR) and eye-tracking software have paved the way for more sophisticated and ecologically valid measures of cognitive function. Testing the sensitivity and reliability of such measurements in response to acute alcohol intoxication provides a first step in establishing how these measures may operate in relation to cognitive impairments observed post-concussion. Healthy young adults (N = 54, M = 20.65, SD = 2.06, 30 females) completed the CONVIRT test battery (manual simple and choice reaction-time and saccade reaction-time) at three breath alcohol concentration (BrAC) levels: 0.00%T1, 0.05%T2, 0.08%T3. Participants consumed alcoholic beverages at 30-min intervals, with BrAC monitored at 15-min intervals using a breathalyser. All three CONVIRT measures were sensitive to changes in cognitive performance induced by alcohol at BrAC levels at or exceeding 0.05%. A composite measure was also sensitive to alcohol intoxication (Cohen's d = .85 at BrAC = 0.05%; d = 1.20 at BrAC = 0.08%). Strong test-retest reliability was observed (all r < .80), with no gender differences noted. CONVIRT measures were reliable and detected dose-dependent changes in alcohol-induced cognitive impairment. Potentially, the ecologically valid measures may assist in better quantifying the effects of conditions such as concussion, on cognitive performance.

Washout kinetics of ethanol from the airways following inhalation of ethanol vapors and use of mouthwash

Introduction: Breath analyzers are commonly used to test for alcohol intoxication, i.e., elevated systemic levels of ethanol, at workplaces and among vehicle drivers. However, local low-dose exposure to ethanol in the mouth or airways may temporarily increase the breath-alcohol concentration (BrAC) without the systemic ethanol level being affected, leading to false positive test results. The aim of this study was to assess the impact of local ethanol exposure on the BrAC.Methods: Eleven healthy adults (six women) were exposed to on average 856 mg/m3 ethanol vapor for 15 min, followed by repeat collection of exhaled breath in Tedlar bags. One hour later, the subjects washed their mouth for 30 s with a typical mouthwash containing 22% ethanol and post-exposure breaths were again collected repeatedly. Negligible systemic uptake of ethanol was confirmed by analysis of blood sampled before, between and after the exposures. Ethanol in breath and blood was analyzed by gas chromatography.Results: No or very low levels (less than 0.002 mg/g) of ethanol were detected in blood at any time point, indicating negligible systemic uptake. The decline in breath was mono-exponential after both exposures with average half times of 0.4 (range 0.3–0.8) min after inhalation exposure and 1.9 (1.1–3.0) min after mouthwash. BrAC levels in the first sample, collected a few seconds after exposure, were 0.14 (0.07–0.13) mg/L after inhalation and 4.4 (2.7–6.0) mg/L after mouth wash. On average, it took 0.5 (0.06–0.7) min and 11 (6–15) min, respectively, for the BrAC to fall below the Swedish statutory limit of 0.1 mg/L air.Conclusion: In practice, use of breath analysis should not be a problem even if the subject inhaled ethanol vapors before the test. In contrast, use of ethanol-containing mouthwash results in a false positive test if sampling is done within 15 min.

Pregaming: A Field-Based Investigation of Alcohol Quantities Consumed Prior to Visiting a Bar and Restaurant District

Background: Investigations examining the association between pregaming, or the consumption of alcohol prior to attending a social gathering or drinking establishment, and blood alcohol concentrations have primarily relied on estimations (i.e., Widmark equation), rather than objective biologic samples, such as breath alcohol concentration (BrAC). Objectives: The current study assessed: (1) pregaming, using quantity-based measures, among a sample of college and non-college affiliated bar patrons, (2) associations between pregaming intensity/status and participant intoxication (BrAC), and (3) whether participants who pregamed were more likely to identify as a hazardous drinker. Methods: 548 bar patrons provided data on the Alcohol Use Disorders Identification Test-Consumption (AUDIT-C) and a single pregaming item assessing quantity of alcohol consumed prior to visiting a bar/restaurant district in 2015. BrAC samples were collected post interview. We used hierarchical linear regression models, respectively, to assess whether pregaming significantly impacted BrAC and whether presence of hazardous drinking predicted pregaming behavior. Results: After controlling for sex, race/ethnicity, age, student status, and Greek affiliation, the linear regression model explained 32.3% (R2 = .323) of the variance of BrAC levels (F(12) = 21.162, p < .001), with 4.30% of the variance explained solely by pregaming (β = 0.014; p < .001). The linear regression model to assess if harzardous drinking behavior (AUDIT-C) significantly predicted pregaming explained 31.2% (R2 = .312) of the variance of pregaming behavior (F(18) = 13.276, p < .001), with 4.2% of the variance explained solely by AUDIT-C scores (β = 0.280; p < .001). Conclusion: Findings further highlight pregaming as a harmful risk behavior linked to elevated levels of hazardous drinking and intoxication.

Correlates of Breath Alcohol Concentration Among Driving Under the Influence Program Clients in Southern California

Understanding factors correlated with breath alcohol concentration (BrAC) at time of arrest for driving under the influence (DUI) may lead to informed rehabilitation programs. This study describes correlations between BrAC at time of arrest and sociodemographic, mental, and physical health, and alcohol-related characteristics among clients in a large California DUI Program. Client reported data ( n = 17,282) were collected at an intake from 2009 to 2014. BrACs ranged from 0.083% to 0.390%, with an average of 0.159% ( SD = 0.051), almost twice the legal limit in the state. Approximately 10.6% of the variance in BrAC was explained by 11 significant correlates. Two sociodemographic factors (age and race/ethnicity) as well as several alcohol-related characteristics were related to higher BrAC levels, whereas comorbid mental and physical health factors played less of a role. Factors associated with BrAC are complex and warrant further investigation to identify causality and inform future interventions.

Alcohol intoxication progressively impairs drivers' capacity to detect important environmental stimuli

RationaleAlcohol intoxication impairs driving skills, leading to an increased frequency of accidents and crash fatalities. Inebriation may specifically impair environmental vigilance, reducing the driver's capacity for attention to stimuli that are relevant to successful navigation. ObjectivesWe examined the separate and interactive effects of breath alcohol concentration (BrAC) and simulated driving scenario on the capacity to correctly identify visual stimuli embedded in the environment. MethodsTen healthy young adult drivers (6 males; 4 females) each performed 4 driving scenarios at each of 3 steady breath alcohol concentration levels (0, 60 and 100 mg/dl). Scenarios were based on speed or distance keeping while navigating a rural 2-lane road in daytime or nighttime conditions. Drivers pressed a button on the steering wheel corresponding to the direction of an arrow (up or down) which appeared briefly on road signs embedded in the environment, either overhead or on the roadside. ResultsIncreasing level of BrAC and subjective scenario difficulty manifested significant, separate, but not interactive influences in association with the number of arrows correctly identified. Significant impairments could be detected at a level of BrAC below the current American limit for legal operation of a motor vehicle. ConclusionsEnvironmental vigilance is subject to impairment by either/both alcohol intoxication and driving conditions.

Examining Differences in Breath Alcohol Concentration (BrAC) Levels and Hazardous Drinking by Smoking Status Among a Sample of College Student Bar Patrons.

While the association between current smoking and alcohol consumption is well known, the relationship between social smoking and alcohol consumption is less understood. The purpose of this study was to examine the association between smoking status and two alcohol consumption measures in a sample of college student bar patrons. The data used in this study was collected in fall 2015. Study participants (N = 415) were college student bar patrons who agreed to complete an interview that assessed smoking status (i.e., regular smoker, social smoker, non-smoker) and two alcohol consumption measures: (1) breath alcohol concentration (BrAC) levels (using a handheld breathalyzer device) and (2) hazardous drinking scores (using the AUDIT-C scale). We conducted one-way ANOVAs with Bonferroni correction to examine differences in BrAC levels and hazardous drinking scores by smoking status. Among sample participants, 25.3% were regular smokers, 14.7% were social smokers, and 60.0% were non-smokers. Smokers had significantly higher BrAC levels than social smokers and non-smokers. Regular smokers also had significantly higher hazardous drinking scores than social smokers and non-smokers. The BrAC levels and hazardous drinking scores of social smokers and non-smokers were not significantly different. The drinking habits of social smokers reflected those of non-smokers and being a regular smoker was associated with higher drinking levels than the rest of the sample. Because of the association found between alcohol consumption and regular smoking, combining efforts to reduce these behaviors in college students might be advantageous.

Witnesses’ memory for events and faces under elevated levels of intoxication

ABSTRACTResearch on alcohol and witness memory has burgeoned over the last decade. However, most studies have tested participants at relatively low breath alcohol concentration (BAC) levels, unrepresentative of those encountered by officers in the field. To examine how higher intoxication levels might impair witness memory for events and faces, the current research tested participants’ ability to recall a mock crime at elevated BAC levels (>.08%). The BAC levels of bar patrons (N = 138) were recorded before witnessing a video-taped mock crime. Participants were then interviewed using free recall and cued questions and shown a six-person target-present or target-absent lineup. Results show that alcohol negatively affected both the quantity and quality of recall. Regardless of question format, alcohol also reduced the percentage of accurate information elicited from witnesses; however, only cued questions increased the percentage of inaccurate information reported. Intoxication had no effect on identification accuracy. These findings suggest that the encoding and storage systems for faces and events may be impacted differently by alcohol. Our results also highlight the importance of including higher BAC levels when examining the effects of alcohol on witness memory.

Drunk-Driver Detection and Alert System (DDDAS) for Smart Vehicles

One of the major causes of road accidents, crashes, mishaps and fatalities globally all over the world is drunk driving. Though driving under intoxication is illegal, even then people restore to such hard-core habits often. In order to combat such risky situation on road, technological innovation needs to be implemented in a cost-effective, efficient and legal manner. This paper discusses design, development and live-performance test of the prototype of drink and drive situation detection and alert cum vehicle control system to minimize road mishaps and enhance public safety on road. It also analyses the response of breath –alcohol semiconductor sensor with respect to variation in distance from source which is critical part of system design. Based upon the recent smart gas sensing and integration of satellite and cellular wireless communication technologies, the proposed device quickly senses the drunken state of the driver during start-up/driving by estimating the equivalent breath alcohol concentration level corresponding to the legally permissible state’s threshold blood alcohol concentration level. On detection of such situation, on-vehicle siren/audio alarm is activated to warn the persons on road and vehicle control system is triggered to lock ignition or stop the fuel inflow to the vehicle. Additionally, ‘alert SMS’ indicating drunk driver location, tracked by onboard GPS receiver, along with vehicle number is communicated remotely to authorized (family members, traffic police) mobile user using GSM cellular network to take appropriate action thereafter. The live experiment results highlighted the successful working performance of the device in-housed at the steering wheel of the vehicle with the drunk driver.

Concussion History, Hazardous Drinking, and BrAC Levels Among a Sample of Bar Patrons, 2015

ABSTRACTBackground: Alcohol consumption and experiencing a concussion are positively correlated. Concussion history has not been examined previously in any alcohol field study (i.e., conducted in a natural setting). Objective: To better understand the relationship between concussion history and alcohol consumption. Methods: We conducted two anonymous field studies among a 2015 sample of bar patrons (N = 544; 62.5% males) in a college town to assess concussion history and two alcohol consumption measures: (1) breath alcohol concentration (BrAC) levels and (2) hazardous drinking scores (based on the AUDIT-C). Next, we conducted a logistic regression analysis to predict concussion history using the two alcohol consumption measures and other potential covariates (i.e., age, gender, race, college student status). Results: Among participants in our sample, the average BrAC level was.070 (SD =.053) and the average hazardous drinking score was 4.7 (SD = 2.5). Less than half of participants indicated that they had experienced a concussion in their lifetime (235; 43.2%). The logistic regression model indicated that hazardous drinking scores were significantly, positively associated with having experienced a concussion, whereas other covariates (i.e., BrAC, age, gender, race, college student status) did not significantly predict concussion history. Conclusions/Importance: Hazardous drinkers were more likely to have experienced a concussion. Therefore, the relationship found in this sample, between hazardous drinking behavior and concussion history, points to hazardous drinking as a possible risk factor for having had a concussion in the past.

Factors Associated with Self-Estimated Breath Alcohol Concentration Among Bar Patrons.

Few studies have examined the context in which drinkers underestimate their breath alcohol concentration (BrAC) in natural drinking environments. This study examined factors associated with bar patrons' self-estimated BrAC in high-risk college town settings. Guided interview and BrAC data were collected from 510 participants recruited as they exited bars located close to large universities: 1 in Florida and 1 in Texas. Participants with the highest measured BrACs underestimated their BrAC levels the most. Findings from multivariable linear regression analysis indicated that BrAC (std β=0.014, p<0.001), number of alcoholic drinks consumed (std β=0.006, p<0.01), and perceived drunkenness (std β=0.024, p<0.001) had significant positive associations with BrAC self-estimates, where the regression coefficients were scaled by values approximately equal to each variable's interquartile range. Among the 321 participants with BrAC levels≥0.08g/dl, 21.2% believed their BrAC was below the legal per se driving limit of 0.08g/dl. Results from a logistic regression analysis indicated that higher levels of perceived drunkenness were associated with better self-recognition that one's BrAC level exceeded the legal driving threshold (OR=3.312, p<0.001). Further, participants under 26years of age had reduced odds of recognizing that their BrAC was greater than 0.079g/dl (OR=0.245, p<0.05). These findings highlight the inaccuracy of self-estimated BrAC when drinking, particularly among younger drinkers. Adjusting for BrAC, situational factors were strongly associated with self-estimated BrAC. Future research is needed to better understand how altering drinking environments may improve accuracy of BrAC self-estimates and deter driving after drinking.

Perceptions of breath alcohol concentration (BrAC) levels among a sample of bar patrons with BrAC values of 0.08% or higher.

Breath alcohol concentration (BrAC) is a commonly used measure of alcohol intoxication. Because of the potential negative consequences of excessive alcohol consumption, it is important to examine how accurately intoxicated individuals can estimate their BrAC values, especially individuals over the legal BrAC driving threshold (i.e., 0.08%). To better understand perceptions of BrAC values among intoxicated individuals, this field study examined actual BrAC values and BrAC range estimates (0.08% and above, 0.02-0.07%, less than 0.02%) among a sample of bar patrons (N = 454) with BrAC levels at 0.08% or higher. Bivariate and multivariate analyses were conducted to examine the relationship between actual BrAC values and perceived BrAC levels. We also examined whether the following demographic and drinking variables were associated with underestimating BrAC in this sample: gender, age, race, college student status, plans to get home, and hazardous drinking. Results indicated that the majority (60.4%) of participants underestimated their BrAC (i.e., less than 0.08%) and lower BrAC values correlated with underestimating BrAC ranges (p < .001, 95% CI[0.2, 0.6]). Further, females (p = .001, 95% CI[1.3, 3.3]) and participants under 21 (p = .039, 95% CI = 1.0, 2.6) were significantly more likely to estimate their BrAC to be less than 0.08%, which is concerning given that young (less than 21) intoxicated females are a group at high risk for sexual assault on college campuses. (PsycINFO Database Record

Characterization of the Pharmacokinetics of Phosphatidylethanol 16:0/18:1 and 16:0/18:2 in Human Whole Blood After Alcohol Consumption in a Clinical Laboratory Study.

The purpose of this study was to characterize the pharmacokinetics of 2 homologues of phosphatidylethanol (PEth) and their combined total in uncoagulated, whole blood samples taken from participants in a human clinical laboratory study after consumption of low doses of ethanol (EtOH). As part of a larger study, 14 male and 13 female participants received either 0.25 or 0.50g/kg oral doses of EtOH during a 15-minute period. Blood samples were collected before and throughout 6hours after each EtOH dose on the day of consumption and then every 3days during the next 14days. PEth 16:0/18:1 and PEth 16:0/18:2 levels were quantified in blood samples by HPLC/MS/MS and reported separately or as their combined total (combined PEth). Breath alcohol concentrations (BrACs) were measured concurrently with each blood collection. Transdermal alcohol concentrations were measured every 30minutes during the entire 22-day study to confirm the absence of drinking during a 7-day period before and the 14-day period after EtOH consumption. (i) Single doses of 0.25 and 0.50gEtOH/kg produced proportional increases in BrAC and combined PEth levels of all participants; (ii) the areas under the curve (AUCs) for each participant's BrAC levels during the 6-hour period after EtOH administration were correlated with AUCs of cPEth (calculated as the AUC of the increase above baseline for combined PEth); (iii) the mean half-life of combined PEth, determined during the 14-day period after EtOH consumption, was 4.6±3.5(SD)days (range: 1.0 to 13.1days). Combined PEth is a sensitive biomarker for the identification of relatively low levels of EtOH consumption. The measurement of these 2 homologues may provide additional sensitivity to identify low levels of drinking.