WHO/ISBRA Study on State and Trait Markers in Alcoholism

The biometric measurement of alcohol consumption

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.

Laboratory Markers Carbohydrate-Deficient Transferrin, γ-Glutamyltransferase, and Mean Corpuscular Volume Are Not Useful as Screening Tools for High-Risk Drinking in the General Population: Results From the Study of Health in Pomerania (SHIP)

BACKGROUND

Assessment of high-risk drinking in the general population can be problematic: questionnaire-based instruments may carry the problem of random or systematic recall bias, and the effectiveness of screening of single biomarkers has been shown to be insufficient. In this article, we analyze the alcohol intake/biomarker relationship of carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and erythrocyte mean corpuscular volume (MCV). Specific aims were (1) screening effectiveness comparison of GGT, CDT, and MCV in terms of sensitivity, specificity, and positive (PPVs) and negative predictive values (NPVs) and the effect of covariates on these measures; (2) the comparison of summary measures for the effectiveness of screening: the receiver characteristic curve (ROC) and the area under the ROC; and (3) to answer the question of which covariates effect which biomarkers and whether accounting for relevant covariates increases the prognostic value of biomarkers to levels that allow for application in the general population.

METHODS

In a representative cross-sectional health survey in northeast Germany with data collection from 1997 to 2001, 4310 men and women were asked for their recent alcohol consumption and smoking. Biomarkers were analyzed from blood samples. The effectiveness of screening of CDT, GGT, and MCV for high-risk drinking (men: >60 g/day, women: >40 g/day) was analyzed with PPV and ROC curve analysis.

RESULTS

For all three biomarkers, PPVs for high-risk drinking are very low (< 50%). There are some effects of covariates on screening effectiveness and on PPV, and knowledge of these covariates increases screening effectiveness, but no subgroup that had a combination of covariate levels and prevalence of high-risk drinking that led to a PPV > 50% could be found.

CONCLUSIONS

: Accounting for covariates in the screening procedure does not lead to a sufficient increase in PPV. Screening effectiveness of laboratory markers CDT, GGT, and MCV is insufficient for their application as screening tools for high-risk alcohol drinking in the general population. This was found using self-reported alcohol consumption as an imperfect gold standard, which is a limitation of the study, although self-reports are the standard instrument in comparable epidemiologic studies.