OBJECTIVE. Blood alcohol concentrations (BACs) in children after consumption of different numbers of standard drinks of alcohol have not been estimated previously. The goal was to determine the number of drinks at each age that led to a BAC of ≥80 mg/dL, the National Institute on Alcohol Abuse and Alcoholism criterion for binge drinking.
METHODS. The updated Widmark equation to estimate BAC was modified to take account of the differing body composition (total body water) and accelerated rates of ethanol elimination of children. The modified formula was used with 1999–2002 National Health and Nutrition Examination Survey data to estimate BACs for >4700 children and adolescents from 9 through 17 years of age, for intake levels of 1 to 5 standard drinks.
RESULTS. The estimated BACs for children after consumption of just 3 standard drinks within a 2-hour period were between 80 and 139 mg/dL for boys 9 to 13 years of age and for girls 9 to 17 years of age, indicating substantial potential alcohol impairment. With 5 drinks within 2 hours (the level used to define binge drinking among college students), children 9 to 13 years of age were estimated to have BACs 2 to 3 times the adult legal limit for intoxication of 80 mg/dL.
CONCLUSION. Binge drinking should be defined as ≥3 drinks for 9- to 13-year-old children, as ≥4 drinks for boys and ≥3 drinks for girls 14 or 15 years of age, and as ≥5 drinks for boys and ≥3 drinks for girls 16 or 17 years of age.
The Surgeon General recently issued a call to action on underage drinking,1 to draw greater public attention to the problem, to encourage more targeted research, and to develop more-effective prevention efforts for the underage population. Another goal was to improve screening instruments to identify children and adolescents who drink or who engage in hazardous levels of drinking.
There continues to be little consensus, however, regarding how drinking and hazardous drinking should be defined. Drinking has been defined as any alcohol use,2 more than a few sips of alcohol,3 or a full drink of alcohol.4 Hazardous drinking is often indicated by “binge drinking,” defined as ≥5 drinks for men or ≥4 drinks for women per occasion.5 This definition is controversial, however.6–9
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) redefined binge drinking as a drinking pattern that brings a person's blood alcohol concentration (BAC) to ≥80 mg/dL, a level accompanied by significant physical and mental impairment.10 For the typical adult, this pattern corresponds to 5 drinks for a man or 4 drinks for a woman within a 2-hour period.
One problem with the NIAAA definition is that it was developed with adults in mind and has not yet been exemplified in younger populations. Both children and early adolescents weigh substantially less than adults and likely would achieve considerably higher BACs with 5 drinks within a 2-hour period or would reach a BAC of ≥80 mg/dL with significantly fewer drinks.
To estimate the BACs that theoretically would result from consumption of various numbers of drinks by children and adolescents, the updated Widmark equation11,12 that is used to estimate BACs in adults needs to be modified so that it relies on more developmentally appropriate estimates of body composition and ethanol elimination rates. As expressed by Brick,13 the updated Widmark formula for peak BAC is as follows: BAC = (A/total body water [TBW]) × 80.65 (eq 1); that for BAC after t hours is as follows: BAC = [(A/TBW) × 80.65] − βt (eq 2), where A is the the weight of ethanol (in grams), TBW is the volume of distribution (in liters; estimated on the basis of an individual's height and weight12), 80.65 is the the percentage of water in blood, β is the the ethanol elimination rate per hour, and t is the time (in hours) since the start of drinking.
The aim of this study is to modify these equations to generate BAC estimates that are more developmentally appropriate for children and early adolescents. It should then be possible to determine the appropriate number of drinks to ask about in questions assessing child or adolescent binge drinking.
This section describes the National Health and Nutrition Examination Survey (NHANES) data and the procedures used to derive child, adolescent, and adult TBW and ethanol elimination rates. Children <9 years of age were not included because they are not likely to consume 1 to 5 full drinks.14 Adults ≥18 years of age were included as a general comparison group.
National Health and Nutrition Examination Survey Data Set
Public-use data from the 1999–2002 NHANES were used to generate estimates of TBW for children, adolescents, and adults. These data reflect the full range of variation possible in estimated TBW values and consequently in potential BACs for children at each age. The NHANES is a stratified multistage probability sample of the civilian, noninstitutionalized, US population. Data from 2 cycles (1999–2000 and 2001–2002) were merged so that each age/gender group would be large enough for the planned analyses. Table 1 presents the distribution of participants according to gender and age (9–17 years and ≥18 years of age). Non-Hispanic black subjects, Mexican American subjects, and adolescents were oversampled. Participation rates for the physical examinations were 76.3% in 1999–2000 and 79.6% in 2001–2002.15
Body weight was assessed by using a Toledo digital scale. Standing height was measured by using an electronic fixed stadiometer. Average weight and height were calculated by using SUDAAN (Research Triangle Institute, Research Triangle Park, NC)16 (Table 2). Few participants were missing data; 98.3% of children and 96.5% of adults had data on both variables. Respondents missing either height or weight data were omitted from the analyses.
Estimation of TBW
The first component of the BAC equation modified for use with children was TBW. In the updated Widmark equation,12,13 regression equations were developed to estimate TBW for adults by using their weight and height. These equations were used here for adults. We located similar equations for children 8 to 20 years of age that predicted their TBW (assessed with deuterium dilution procedures) by using their height and weight.17 That study determined the best regression weights (multipliers) to use with children's height (in centimeters) and weight (in kilograms) to estimate their measured TBW (in liters), as follows: for boys, TBW = −25.87 + (0.23 × height) + (0.37 × weight) (eq 3); for girls, TBW = −14.77 + (0.18 × height) + (0.25 × weight) (eq 4). Table 2 reports the mean estimates of TBW according to gender and age, as calculated from the NHANES data.
Establishment of Ethanol Elimination Rates for Children
Child and adolescent rates of ethanol elimination for the modified BAC equations were derived from 4 published studies18–21 (which were identified by using Medline) of emergency department (ED) presentations with alcohol intoxication or poisoning by children and adolescents 9 to 17 years of age (the ages of interest here), in which BAC was measured at least twice, permitting determination of hourly ethanol elimination rates. There were a total of 46 patients 9 to 17 years of age (22 male patients and 24 female patients) in those studies (including 37 from 1 study21). Of those, only 4 patients had 3 BAC assessments and 1 patient had 4 assessments before the start of dialysis.20 BAC was determined through gas chromatography in 2 studies,18,21 whereas the procedure used was not mentioned in the other 2 studies, which accounted for just 5 of the 46 cases.19,20 For consistency across studies, hourly ethanol elimination rates for individuals were calculated by dividing the difference between the first BAC and the last BAC by the time elapsed in hours and converting values from millimoles per liter per hour to milligrams per deciliter per hour where necessary by dividing by 0.217. Serum ethanol elimination rates (from the report by Simon et al21) were then converted to blood elimination rates by dividing by 1.10.13
To examine age differences, all 46 ED cases were assembled into a single data set. Three patients were excluded, that is, a 15-year-old male patient20 with an extreme outlying rate of 53.8 mg/dL per hour and two 16-year-old patients21 (1 male patient and 1 female patient) with suspiciously low rates (<7 mg/dL per hour22). Table 3 presents the mean and SD for each age group. As can be seen, there is a substantial decrease of >1 SD in the mean elimination rate between 12 and 13 years of age (from 20.95 to 15.87 mg/dL per hour) but no additional consistent decreases. Fluctuation in the means for ages 13 to 17 is likely attributable to the small number of patients at each age. Because no extant theory justifies establishing a separate rate for the age 15 group (Table 3) or categories in adolescence whose elimination rates decrease (at ages 13–14) and then increase (at ages 15–17) before decreasing in adulthood, it was decided to retain just 2 age categories (ages 9–12 vs 13–17). Analyses of variance revealed a statistically significant difference in their elimination rates (23.75 ± 6.19 mg/dL per hour and 16.79 ± 4.55 mg/dL per hour, respectively; F1,41 = 12.2, P < .001), accounting for 23% of the variance. Two-way analyses of variance (2 × 2; observed power: 0.85) also found a nonsignificant gender effect (P = .31) and age-gender interaction (P = .22). Therefore, 2 different ethanol elimination rates were used in the BAC equations, 1 for 9- to 12-year-old subjects (23.75 mg/dL per hour) and 1 for 13- to 17-year-old subjects (16.79 mg/dL per hour).
SPSS 16 (SPSS Inc, Chicago, IL) was used to calculate estimated BACs after 1 to 5 standard drinks for boys and girls at each age from 9 through 17 years and for adults ≥18 years of age. A standard drink was defined as 0.6 oz of absolute alcohol or 14 g of ethanol, which translates into 12 oz of beer (5% alcohol by volume), 5 oz of wine (12% alcohol by volume), or 1.5 oz of 80-proof distilled spirits (40% alcohol by volume).13,23 BAC means and 95% confidence intervals (CIs) were generated from the NHANES data by using estimated TBW values derived from the height and weight data.
Two BAC estimates were calculated, that is, the theoretical maximal BAC (peak BAC) after full absorption of the alcohol consumed (eq 1) and the BAC achieved 2 hours later (eq 2). For the latter, the focus was on time since peak BAC, because the ethanol elimination rates derived above were measured on the descending limb of the absorption curve (after children's arrival at the ED, usually hours after the start of drinking and presumably after achievement of peak BAC). In eq 2, the time since peak BAC (ie, t) was set at 2 hours for consistency with the NIAAA definition of binge drinking, and the aforementioned age-appropriate ethanol elimination rates were used for children and adolescents. For adults, an average ethanol elimination rate of 15 mg/dL per hour was used.24 The DESCRIPT procedure in SUDAAN 10.016 was used to calculate the means and 95% CIs of estimated BAC values. SUDAAN uses Taylor series linearization procedures to estimate variances for complex survey data.
Estimated Peak BACs According to Intake
Table 4 presents estimates of the maximal theoretical BAC (peak BAC), after 1 to 5 standard drinks, for boys and girls at each age from 9 through 17 years. In general, consumption of greater numbers of standard drinks yielded higher estimated BAC values at each age. It is also clear that younger children had higher estimated mean BAC values at each level of alcohol intake. For ages 9 to 13, the estimated peak BACs for boys and girls were comparable at each level of alcohol intake (because of similar mean weights and TBWs). The mean BAC for girls were within the 95% CI for boys at each of those ages. For ages 14 to 17, there were sizable gender differences; estimated BACs were higher for girls than for boys at each intake level, with no overlap in their 95% CIs. Children and adolescents had higher estimated BACs than did adults at each level of alcohol intake.
At 1 standard drink, boys and girls could theoretically achieve peak BACs ranging from 62.0 mg/dL for 9-year-old boys to 27.4 mg/dL for 17-year-old boys and from 61.9 mg/dL for 9-year-old girls to 38.2 mg/dL for 17-year-old girls. At 2 drinks, the estimated peak BACs for girls 9 to 13 years of age exceeded 80 mg/dL (range: 81.8–123.9 mg/dL), whereas only those for boys 9 to 12 years of age reached this level (range: 84.6–124.0 mg/dL). At 3 drinks, the estimated peak BACs for all children 9 to 17 years of age exceeded the 80 mg/dL NIAAA criterion, and BACs were 2.3 times this level for the youngest children (ie, 186.0 and 185.8 mg/dL for 9-year-old boys and girls, respectively). At 5 standard drinks, estimated peak BACs ranged from 137.1 to 309.9 mg/dL for boys and from 191.1 to 309.7 mg/dL for girls, levels that can result in coma and respiratory problems in children and early adolescents.25
Estimated BACs 2 Hours After Peak Levels
Table 5 presents the BAC estimates for 2 hours after absorption of 1 to 5 standard drinks. As reported above, consumption of more standard drinks at each age yielded higher estimated BACs. Also, younger children had higher estimated postpeak BAC values at each intake level. For ages 9 to 13, the mean estimated BACs for boys and girls were comparable at each level; mean BACs for girls were within the 95% CI for boys of the same age. For ages 14 to 17, girls had higher estimated BACs than did boys at each intake level, with no overlap in their 95% CIs. The same was true for adults. Children and adolescents exhibited higher estimated BACs than did adults at each level of alcohol intake.
According to the modified Widmark equation, there would be little or no unmetabolized alcohol for either gender 2 hours after absorption of 1 drink; estimated mean BACs varied from only 0.2 to 15.4 mg/dL for boys and from 5.1 to 14.5 mg/dL for girls. With 3 drinks, the estimated postpeak BACs were ≥80 mg/dL for girls 9 to 17 years of age. Among boys, only estimates for those 9 to 13 years of age exceeded 80 mg/dL with 3 drinks. With 4 standard drinks, the estimated BACs exceeded 80 mg/dL for girls of all ages, for adult women, and for boys 9 to 15 years of age. With 5 standard drinks, estimated postpeak BACs ranged from 103.6 to 262.4 mg/dL for boys and from 157.5 to 262.2 mg/dL for girls. BAC values greater than ∼150 mg/dL place children and early adolescents at high risk for coma and respiratory difficulties.25
Alcohol use by children carries substantial risks for long-term psychiatric and psychosocial consequences. The younger the age at which alcohol use is initiated, the greater is the risk for problem drinking in adolescence and for alcohol abuse or dependence in adulthood,26–30 as well as for other problematic outcomes in adolescence, including school absences, delinquent behavior, drinking and driving, smoking, use of marijuana and other drugs, sexual intercourse, and pregnancy.28,31,32
In addition, there are acute risks stemming from the higher than heretofore recognized BACs that can result from drinking by children and youths in early to middle adolescence. The present findings suggest that substantially fewer drinks are needed to result in high BAC values in children. At present, however, the expected effects of these BACs in children and adolescents are largely theoretical. Only a single experiment with a small sample (22 boys, 8–15 years of age) has examined the effects of alcohol at a single moderate BAC (35 mg/dL).33 Although results from that pilot study have been widely interpreted as indicating decreased ethanol sensitivity in children and adolescents, more evidence with larger samples and higher BACs, perhaps from ED studies, is clearly needed. Animal models suggest reduced adolescent sensitivity to the sedative effects of alcohol,34 but generalization to human children demands greater caution.
The present results have implications for the operational definitions of drinking, binge drinking, and heavy drinking. With respect to drinking, results show that, with 1 standard drink, peak BACs were estimated as 30 to 60 mg/dL, which in adults would result in feelings of relaxation, intoxication, lightheadedness, and euphoria at the lower end of the range and reduced coordination, increased sociability, lowered inhibitions, decreased alertness and caution, and impaired reasoning, memory, and judgment at the higher end.35 To the extent that children experience the same effects at these BACs, it is clearly possible for them to experience ethanol's positive physical and psychological effects after drinking less than a full drink, even at approximately one half of a drink. Consumption of a full drink is thus too stringent a criterion for determination of which children are drinkers.4 This decision might better hinge on children having experienced the rewarding effects of alcohol (eg, relaxation, euphoria, and increased sociability), because research has shown that expectations of experiencing such positive effects increase the likelihood of drinking initiation and problem drinking in adolescence.36–38
The present findings also suggest that substantially lower cutoff points should be used to define binge drinking for children and adolescents. The estimated mean BACs exceeding 80 mg/dL 2 hours after peak levels suggest that cutoff points for binge drinking for boys should be set at ≥3 drinks for 9- to 13-year-old boys, ≥4 drinks for 14- to 15-year-old boys, and ≥5 drinks for 16- to 17-year-old boys. For girls 9 to 17 years of age, the cutoff point for binge drinking should be set at ≥3 drinks. Intake of fewer drinks than these at each age should not be considered safe, however. The higher estimated BACs for girls than for boys at ages 14 to 17 (and lower cutoff points) are likely attributable to the larger muscle mass of boys after puberty, and hence their greater TBWs (Table 2).
These results also indicate that the operational definition of heavy drinking should be modified for children and adolescents. In the National Survey on Drug Use and Health,39 heavy drinking refers to binge drinking on ≥5 days in the past month. The use of a more developmentally appropriate measure of a binge would result in higher prevalence rates of heavy drinking among adolescents.
For pediatricians, nurse practitioners, and others involved in child and adolescent health care, the implications of the present BAC estimates and recent epidemiological evidence on children's drinking14 are that the practitioners should screen children as well as adolescents for alcohol use and they should intervene at substantially lower levels of alcohol involvement than previously thought. Treating only ≥5/≥4-drink binges as evidence of hazardous drinking would miss younger children who are at substantial risk for impaired intellectual functioning and decreased school achievement resulting from “child-sized” binges that expose their brains to boluses of alcohol that have been shown to affect such outcomes in adolescents.40
Given the opportunistic nature of children's drinking, these results likely underestimate actual BACs at each intake level, because children, like college students,41 are likely to pour larger than standard drinks. These figures likely overestimate BACs at each intake level for children in countries that use smaller standard drink sizes (eg, the United Kingdom, Australia, and New Zealand).
The higher ethanol elimination rates for children, compared with adolescents, that were used here are generally consistent with drug metabolism rate differences between children and adults.42 Children's livers are larger for their body size than are those of adults until ∼16 years of age.43,44 Although the activity levels of alcohol dehydrogenase45 and the cytochrome P450 isozyme CYP2E146–48 in the human liver do not change between 9 and 17 years of age, the age-related differences in relative liver size imply that there may well be greater overall oxidizing capacity present in children's livers, accounting for their faster ethanol elimination rates.33 ED studies of ethanol elimination in larger samples of alcohol-involved children and adolescents are needed to determine age differences in these rates more definitively.
The absence of direct measures of TBW is an important limitation of the present research. Although the predicted TBW values captured the full range of TBW values in US children 9 to 17 years of age, the means presented should not be used as national estimates, because of the lack of availability of anthropometric regression equations for minority children. This lack of availability not only introduced some bias but also prevented racial/ethnic comparisons of the estimated BACs.
Reliance on an updated and more developmentally appropriate Widmark equation for estimation of BACs for children and adolescents does not escape the inherent limitations of this equation. First, it assumes that all of the alcohol is ingested at once, rather than over a period of time. Second, it assumes that the person is in a fasting state, an assumption that is hard to imagine for an adolescent boy. Third, it does not acknowledge the wide variability among individuals in rates of alcohol absorption and elimination. The present use of the equation does minimize some of the sources of uncertainty in this equation noted by Gullberg49; the number of drinks was certain, the alcohol content of a drink was standardized, weight was measured and not estimated, and TBW was estimated from weight and height data, rather than from the conversion factors described by Widmark.11 Despite being based on large numbers of individuals, however, these BAC estimates still have uncertainty because of potential errors in the estimation of both TBW and ethanol elimination rates. It is hoped that future research will provide better estimates for both.
The major limitation of the study is, of course, its reliance on an equation for the estimation of children's BACs that was not developed through alcohol administration experiments with children and adolescents. Therefore, these estimates should be considered theoretical and should not be used in pediatric forensic applications. They are at best heuristic approximations developed to advocate against the use of adult operational definitions of hazardous alcohol use in the younger population. Their main virtue is that they are potentially more accurate estimates of child and adolescent BACs than are those based on the standard Widmark equation, which relies on adult reference values.
This research was funded by NIAAA grant AA012342.
I thank Drs Ting-Kai Li and Ralph Hingson for their encouragement to develop this article.
- Accepted February 12, 2009.
- Address correspondence to John E. Donovan, PhD, Western Psychiatric Institute and Clinic, University of Pittsburgh Medical Center, 3811 O'Hara St, Pittsburgh, PA 15213. E-mail:
The author has indicated he has no financial relationships relevant to this article to disclose.
This work was presented in part at a National Institute on Alcohol Abuse and Alcoholism Underage Drinking Initiative meeting; Screening for Childhood and Adolescent Drinking and Alcohol Use Disorders among Youth, June 11, 2007; Bethesda, MD.
What's Known on This Subject
BACs have not been estimated previously for child and adolescent drinking. Developmentally appropriate estimates are important for determination of how many standard drinks constitute binge drinking in this population, an important benchmark for prevention, screening, and research.
What This Study Adds
This study modifies the updated Widmark equation so that it is developmentally appropriate, and it uses NHANES 1999–2002 data to derive age- and gender-specific definitions of binge drinking appropriate for boys and girls 9 to 17 years of age.
- ↵Office of the Surgeon General. The Surgeon General's Call to Action to Prevent and Reduce Underage Drinking. Rockville, MD: Office of the Surgeon General; 2007
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- ↵Research Triangle Institute. SUDAAN Language Manual, Release 10.0. Research Triangle Park, NC: Research Triangle Institute; 2008
- ↵Leung AKC. Ethyl alcohol ingestion in children: a 15-year review. Clin Pediatr (Phila).1986;25 (12):617– 619
- ↵US Department of Agriculture. Dietary Guidelines for Americans. 6th ed. Washington, DC: US Department of Agriculture and US Department of Health and Human Services; 2005
- ↵Pohorecky LA, Brick J. Pharmacology of ethanol. In: Bafour DJK, ed. Psychotropic Drugs of Abuse. New York, NY: Pergamon; 1990:189– 281
- ↵Lamminpää A. Alcohol intoxication in childhood and adolescence. Alcohol Alcohol.1995;30 (1):5– 12
- ↵Ellickson PL, Tucker JS, Klein DJ. Ten-year prospective study of public health problems associated with early drinking. Pediatrics.2003;111 (5):949– 955
- ↵Bailey WJ. Drug Use in American Society: An Epidemiologic Analysis of Risk. 3rd ed. Edina, MN: Burgess Publishing; 1993:143
- ↵Substance Abuse and Mental Health Services Administration. Results from the 2006 National Survey on Drug Use and Health: National Findings. Rockville, MD: Office of Applied Studies; 2007. NSDUH Series H-32, DHHS Publication SMA 07–4293
- ↵Clein PD, Riddle MA. Pharmacokinetics in children and adolescents. In: Lewis M, ed. Child and Adolescent Psychiatry: A Comprehensive Textbook. 2nd ed. Baltimore, MD: Williams & Wilkins; 1996:765– 772
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- ↵Blanco JG, Harrison PL, Evans WE, Relling MV. Human cytochrome P450 maximal activities in pediatric versus adult liver. Drug Metab Dispos.2000;28 (4):379– 382
- Johnsrud EK, Koukouritaki SB, Divakaran K, et al. Human hepatic CYP2E1 expression during development. J Pharmacol Exp Ther.2003;307 (1):402– 407
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