AGE-RELATED DIFFERENCES IN BLOOD ETHANOL PARAMETERS AND SUBJECTIVE FEELINGS OF INTOXICATION IN HEALTHY MEN

Abstract

Healthy men within 4 age groups, 20–29, 30–39, 40–49 and 50–59 years ( N = 12 per group), drank 0.68 g/kg ethanol as neat whisky after fasting overnight. The drink was finished within 20 min and the concentrations of ethanol in capillary blood were determined at 30/60 min intervals for 7 hr. At the time of blood sampling, the men were asked to estimate their feelings of intoxication according to an arbitrary scale on which the score 10 indicated ‘tipsy’ or a ‘Little high’. The time course of blood ethanol concentration was similar in all 4 groups with the curve for 50–59-year-old men on the highest level and 20–29-year-old men lowest. Subjective intoxication scores were significantly less in the youngest age group and the maximum score for each subject was correlated with age ( r = 0.45, P ≪ 0.01). Total body water (TBW) was not correlated with age directly ( r = 0.17, P > 0.05) but when it was expressed as percent of body weight a strong negative correlation was found ( r = −0.77, P > 0.001). The mean total body water estimated from ethanol dilution was 46.7 ± 4.11. (+ SD, N = 48) and this corresponds to 58% of mean body weight of the men. The distribution volume of ethanol/kg body weight ( Vd ) decreased with ageing ( r = −0.59, P < 0.001) being 0.72, 0.71, 0.68 and 0.66 l/kg on average in the 20–29, 30–39, 40–49 and 50–59-year-old age groups respectively. The reduction of Vd corresponds to an age-related decrease in the percentage of body water and an increase in the percentage of body fat. This results in elevated blood ethanol concentrations in older individuals for a constant dose/kg body weight. The absorption of ethanol from the gut and its rate of disappearance from blood were not markedly influenced by age. The lower subjective feelings of intoxication reported by younger men may indicate that age-related differences in acute functional tolerance to ethanol or different threshold values of blood ethanol may exist before an effect is felt.