Assessment of heavy alcohol drinking among young Swiss men

Abstract

There is a need of empirical evidence of the relationship between heavy alcohol use and alcohol markers. More precisely, associations of these markers with patterns of alcohol use, such as risky single occasion drinking (i.e., drinking 6 drinks or more on a single occasion) have been scarcely investigated. This study aimed to derive psychometric properties of alcohol markers in comparison with different measures of alcohol use and to test whether it allows detecting excessive alcohol use. Participants ( n = 233, male, around 20 years old) were recruited based on a stratified random selection of the Swiss Cohort Study on Substance Use and Risk Factors. Inclusion criterion was an Audit score ≥ 13. Assessments included a clinical interview based on the Diagnostic Interview for Genetic Studies (DIGS) and self-reported alcohol measures [1] . Hair ( n = 230) and capillary blood ( n = 233) on Hemaxis ® DBS device were collected for ethyl glucuronide (EtG) and phosphatidylethanol (PEth) determination, respectively. EtG was extracted from washed hair by micropulverized extraction and SPE purification. The extracts were submitted to LC-MS/MS analysis (6500 Qtrap Sciex). Chromatographic separation was achieved using a Merck Chromolith ® RP-C18e column (150 × 3 mm). The PEth homologs 16:0/18:1 and 16:0/18:2 concentrations were determined by LC-MS/MS (5000 Qtrap Sciex) according to a validated method [2] . For the interpretation, only the PEth homolog 16:0/18:1 were used. Statistical data treatment (ROC-analysis) was carried out using R software. EtG could be detected in 151 of 230 samples with concentrations ≥ 4.0 pg/mg (LOQ). The maximum measured concentration was 690 pg/mg. Twenty-five percent, 50% (median) and 75% percentiles were 6.8, 15, and 34 pg/mg, respectively. In 53 cases, EtG concentrations were ≥ 30 pg/mg, suggesting excessive alcohol consumption. The area under the ROC curve for EtG ≥ 30 pg/mg vs. PEth was 0.8322. In cases where PEth ≥ 210 ng/mL, more than 75% presented also EtG ≥ 30 pg/mg. PEth 16:0/18:1 detected in 218 of 233 samples with concentrations ≥ 10 ng/mL (LOQ). The maximum measured concentration was 1990 ng/mL. Twenty-five percent, 50% (median) and 75% percentiles were 71, 182, and 360 ng/ml, respectively. In 99 cases, PEth 16:0/18:1 concentrations ≥ 210 ng/mL, suggesting excessive alcohol consumption, were found. Compared to self-reported data (last week total alcohol intake diary), area under the ROC curve for PEth ≥ 210 ng/mL were 0.8174. For detecting a risky single occasion drinking (≥ 5 drinks at one occasion), the area under the ROC curve for PEth were 0.7955. EtG and PEth measurement allowed detecting excessive alcohol consumption with high specificity and sensitivity. Both marker are complementary and do not necessarily provide the same information because of their different detection window and change of consumption during the evaluation period. The results support the statement in the SoHT consensus for the use of alcohol markers: “It is not advisable to use the results of hair testing for alcohol markers in isolation” [3] .