The biometric measurement of alcohol consumption

Abstract

Background: Proper ascertainment of the history of alcohol consumption by an individual is an important component of medical diagnosis of disease and influences the implementation of appropriate treatment strategies that include prescription of medication, as well as intervention for the negative physical and social consequences of hazardous/harmful levels of alcohol consumption. Biological (biometric) diagnostic tests that provide information on current and past quantity and frequency of alcohol consumption by an individual, prior to onset of organ damage, continue to be sought.

Methods: Platelet monoamine oxidase B (MAO-B) protein was quantitated in 2 populations of subjects who had histories of different levels of alcohol consumption. Levels were assayed by immunoblotting or by ELISA. The development and evaluation of the new ELISA-based measure of platelet MAO-B protein levels is described.

Results: One subject population constituted a nontreatment-seeking, cross-sectional subject sample, and the other population was a longitudinally followed, hospitalized group of subjects. An algorithm combining measures of platelet MAO-B protein with the plasma levels of carbohydrate-deficient transferrin (CDT) and with liver enzymes (aspartate aminotransferase or γ-glutamyltransferase [GGT]) can detect hazardous/harmful alcohol use (HHAU) with the highest sensitivity and specificity in the cross-sectional nontreatment-seeking population. In the treatment-seeking population, low MAO-B protein levels at admission are associated with heavy drinking prior to admission, and these protein levels increase over a period of abstinence from alcohol.

Conclusions: The platelet MAO-B protein measurement is particularly effective for male alcohol consumers. The combined use of MAO-B protein measures together with measures of CDT and GGT does, however, improve the diagnostic utility of both markers for ascertaining HHAU in women. Furthermore, measurement of changes in platelet MAO-B protein levels during treatment for alcohol dependence may help monitor the success of the treatment program.

Fig. 1

Averaged standard curves of standard platelet proteins used for quantitative immunoblotting with associated curve fit. Units on abscissa are optical density units adjusted for volume of immunoreactive bands on film. Values in parentheses are the %CV of 3 measurements at each protein amount (each measurement represents the average of triplicates from each of the 3 standard curves).

Fig. 2

Averaged standard curves of recombinant monoamine oxidase B (MAO-B) used for ELISA measures of MAO-B in platelets. Units on the abscissa are the optical densities (OD) read at 450 nm using a BioTek LX800 plate reader. Values in parentheses are the %CV of the 3 measurements at each recombinant MAO-B protein concentration (each measurement is the average of triplicates in each standard curve).

Fig. 3

Representative plot of the working concentrations of platelet protein established for the monoamine oxidase B (MAO-B) ELISA.

Fig. 4

Platelet monoamine oxidase B (MAO-B) protein levels associated with hazardous/harmful alcohol use (HHAU) and nonhazardous alcohol use (NHAU) in subjects with and without antisocial personality disorder (ASPD). MAO-B platelet protein levels associated with HHAU or NHAU are illustrated for male WHO/ISBRA subjects with or without a lifetime diagnosis of ASPD. Note that 1 ASPD subject (Table 1) was Asian, and was excluded from this analysis. Data represent least squares means from a 2-way ANOVA. *p < 0.0001, HHAU compared to NHAU (t-statistic for individual contrasts).