Ethyl glucuronide in hair of non-excessive alcohol consumers: correlations and gender influence.

Hair ethyl glucuronide (hEtG) is a marker used for previous alcohol consumption. Correlations have been reported between the amount of alcohol consumed and hEtG concentration, but little has been published regarding relatively low levels of alcohol consumption and associated hEtG concentrations close to the limit of quantification (LOQ). Here, we investigate hEtG concentrations in non-excessive (<60 g/day) alcohol consumers and address the role of gender differences in hEtG concentration within this population. Daily alcohol consumption over a period of 3 months prior to hair collection was assessed using the Timeline Followback interview in 130 non-excessive (<60 g/day) alcohol consumers. Participants showed large variation in consumption, ranging from 10 g (~1 unit) to 3300 g (~330 units), during the prior 3 months. Eight individuals abstained from alcohol and served as a control group. HEtG was measured using gas chromatography–mass spectrometry in hair segments 0–3 cm in length, and varied from <LOQ to 29.8 pg/mg, showing a linear correlation with the amount of alcohol consumed (r = 0.81; p < 0.001). Gender had no influence on this correlation (gender effect: p < 0.001) or on the detection of nominal hEtG concentrations (p < 0.001). In conclusion, our results showed a correlation between hEtG and the amount of alcohol consumed, with no difference shown based on gender, for non-excessive alcohol consumption, confirming earlier results for excessive alcohol drinkers. We thus propose lowering the current hEtG cut-off value for abstinence assessment to <5 pg/mg.