title: Interpretation of group-level factors from a large population dataset in the determination of ethyl glucuronide in hair.
abstract: Ethyl glucuronide in hair (HEtG) is the most accredited marker to prove chronic alcohol abuse. In this study, we evaluate the comprehensive results of HEtG determination obtained during four years of activity (2009-2013) in our laboratory (Northwestern Italy) - across a large cohort of subjects (over 20 000 subjects mostly undergoing medical examination for driving re-licensing) - to provide a general perspective on HEtG analysis and dependence on group-level factors (e.g. age, gender, site and period of hair collection) that could bias the analytical results. HEtG was measured by liquid chromatography-tandem mass spectrometry. About 12% of the subjects presented HEtG concentrations over 30 pg/mg. Upon non-parametric hypothesis tests, distributions of HEtG in independent populations categorized by age proved statistically different, while no differences were found by considering gender, BMI, and site of sampling (head vs. chest hair). A 'seasonality' factor was evaluated by comparing periods of collection approximately representing the hair growth in winter, spring, summer and autumn, and a seasonal trend was observed showing the highest HEtG levels in winter (16.7%) and minimum levels in summer (8.3%). The experimental HEtG distributions confirm that chest hair sampling can be trusted as an alternative to scalp. Furthermore, among biological and external factors, age and 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.
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.
authors: Alberto
authors: A
authors: Salomone
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.|Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, 10125, Torino, Italy.
authors: Valentina
authors: V
authors: Pirro
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.
authors: Tonia
authors: T
authors: Lombardo
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.
authors: Daniele
authors: D
authors: Di Corcia
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.
authors: Sergio
authors: S
authors: Pellegrino
authors: Centro Regionale Antidoping e di Tossicologia 'A. Bertinaria', Regione Gonzole 10/1, 10043, Orbassano, Torino, Italy.|Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, 10125, Torino, Italy.
authors: Marco
authors: M
authors: Vincenti
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000437:Alcoholism / Q000175:diagnosis; D016208:Databases, Factual; D005260:Female; D005965:Glucuronates / Q000032:analysis*; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D012621:Seasons; D012737:Sex Factors; D015813:Substance Abuse Detection / Q000379:methods; D055815:Young Adult
chemical_list: D005965:Glucuronates; C093924:ethyl glucuronide
keywords: alcohol; ethyl glucuronide; hair; hypothesis tests; seasonality