Time Delays in Transdermal Alcohol Concentrations Relative to Breath Alcohol Concentrations

Abstract

Aims: Monitors of transdermal alcohol concentration (TAC) provide an objective measurement of alcohol consumption that is less invasive than measurements in blood, breath or urine; however, there is a substantial time delay in the onset of TAC compared to blood or breath alcohol concentrations (BrACs). The current study examined the characteristics of the delay between peak TAC and peak BrAC.

Methods: Data was aggregated from three experimental laboratory studies (N = 61; 32 men, 29 women) in which participants wore a TAC monitor and BrAC was monitored while drinking one, two, three, four and five beers in the laboratory. Analyses examined the sex- and dose-related differences in peak BrAC and TAC, the time-to-peak BrAC and TAC, and time lag between the peak BrAC and TAC values.

Results: The times-to-peak were an increasing function of the number of beers consumed. At each level of beer consumption the peak TAC averaged lower than peak BrAC and times-to-peak TAC were longer than for BrAC. The time-to-peak BrAC and TAC was longer for women than men. The congruence between peak TAC and BrAC increased as a function of the beers consumed. No sex difference in the time lag between peak BrAC and TAC was detected.

Conclusions: The congruence between TAC and BrAC and time lags between TAC and BrAC are related to the number of beers consumed. Peak values of TAC and BrAC became more congruent with higher doses but the time lag increased as a function of the amount of alcohol consumed.

Short summary: The time delay (or lag) and congruence between transdermal vs. BrACs increases as the number of beers increases. Though sex differences are evident in peak transdermal and BrACs, no sex differences were evident in the time lag and the congruence between transdermal and breath alcohol concentrations.

Fig. 1.

Time course of TAC and BrAC for men and women. The curve-fitted TAC and BrAC time-course functions for men and women consuming one to five beers. Generalized additive models (GAM) were used to produce overall smoothed curves of TAC or BrAC as curve-fitted functions of time.

Fig. 2.

Time-to-peak BrAC and time-to-peak TAC as a function of the number of beers consumed. The average time in minutes to (A) peak BrAC and (B) peak TAC for women and men consuming one to five beers. A total of 24 TAC observations from the one beer condition and three from the two beer condition were removed prior to analyses due to having peak TAC = 0. All participants had a measureable BrAC; and no other observations were removed

Fig. 3.

The time lag between TAC and BrAC as a function of the number of beers consumed. A scatterplot of the association between the number of beers consumed and time lag (i.e. time-to-peak TAC minus time-to-peak BrAC). Data are all values collected from all participants across all drinking days

Fig. 4.

Peak TAC-to-peak BrAC ratios of men and women as a function of the number of beers consumed. The average peak TAC-to-BrAC ratio of women and men as a function of the number of beers consumed. All observations are present including n = 27 participants who had peak TAC = 0 after drinking one or two beers.