O13: Interpretation of hair ethyl glucuronide inter-individual factors from large population dataset

Abstract

Introduction Ethylglucuronide in head hair (HEtG) is nowadays the most accredited marker to prove chronic alcohol abuse, due to its undeniable performances in terms of discrimination between high-risk and low-risk alcohol drinkers. Among scientific societies, many efforts have been made to prepare consensus documents and protocols, so as to regulate the interpretation of analytical results and the consequent clinical/legal judgments. Nevertheless, warnings about the general applicability of the HEtG have been recently raised. In this study, we summarize the results of the HEtG determination across a large cohort of subjects (n=20,293), that have been obtained over 4 years of activity (2009-2013) in our lab in Orbassano (Piedmont, Italy). Our aim was to provide a general perspective of HEtG determination and investigate if age, gender, BMI, period of sampling, and site of hair collection could bias the analytical results. The experimental results were interpreted by statistical analysis, on the assumption that large population datasets will provide similarly-shaped distributions, leveling off the specific contribution of individual alcohol consumption. Methods Hair samples were collected from medical commissions for driving relicensing located in Piedmont, Italy. These medical commissions examine drivers who are called to prove low-risk intake of alcohol by means of HEtG analysis, using 30 pg/mg as a cut-off value. HEtG was determined by HPLC-MS/MS, as previously published [ V. Pirro et al. Forensic Sci. Int. (2011) 210:271–277 ]. Results The examined population consisted mainly of male subjects (93%). The majority of them (48%) was aged above 40 years (n=9731), while 29% was in the range 31–40 (n=5878) and 23% was in the age ranging 18–30 (n=4684). The Yate's Chi-square, Krushall- Wallis and Mann-Whitney tests were applied to compare HEtG level distributions for all samples showing a measurable concentration, 12% of whom presented HEtG concentrations over 30 pg/mg. A significant distribution difference (P-values Conclusion The experimental HEtG distributions conclusively confirm that chest hair sampling can be trusted as an alternative to scalp. Furthermore, among biological and external factors, the season of sampling may significantly influence the measured HEtG concentration, and this potential source of bias should be taken into account when the results are interpreted.