Fatty acid ethyl esters in hair as markers of alcohol consumption. Segmental hair analysis of alcoholics, social drinkers, and teetotalers.

BACKGROUND

Fatty acid ethyl esters (FAEEs) are products of nonoxidative ethanol metabolism. After incorporation in hair, they should be suitable long-term markers of alcohol abuse.

METHODS

Hair samples from 19 alcoholics in a treatment program, 10 fatalities with verified excessive alcohol consumption, 13 moderate social drinkers who consumed up to 20 g ethanol/day, and 5 strict teetotalers were analyzed in 1-12 segments for four FAEEs (ethyl myristate, ethyl palmitate, ethyl oleate, and ethyl stearate) by external degreasing with n-heptane, extraction with a dimethyl sulfoxide-n-heptane mixture, headspace solid-phase microextraction of the extracts, and gas chromatography-mass spectrometry with deuterated internal standards. The n-heptane washings were analyzed in the same way for FAEEs from the hair surface.

RESULTS

The sum of the four ester concentrations in hair calculated for the proximal 0-6 cm segment was 2.5-13.5 ng/mg (mean, 6.8 ng/mg) for the fatalities, 0.92-11.6 ng/mg (mean, 4.0 ng/mg) for 17 of the alcoholics in treatment, 0.20-0.85 ng/mg (mean, 0.41 ng/mg) for the moderate social drinkers, and 0.06-0.37 ng/mg (mean, 0.16 ng/mg) for the teetotalers. In almost all cases the segmental concentrations increased from proximal to distal. There was no agreement between the self-reported drinking histories of the participants and the FAEE concentrations along the hair length. Ethyl oleate was the dominant ester in all samples.

CONCLUSIONS

FAEEs are deposited in hair mainly from sebum. Despite large individual differences, FAEE hair concentrations can be used as markers for excessive alcohol consumption with relatively high accuracy.