Age, drinking habits and the effects of alcohol.

Some explanations for the common observation that older persons drink less alcohol than younger persons were tested in a sample of 41 men social drinkers aged 19-63. Subjects reported their drinking habits and performed balance beam and bead-stringing tasks under a moderate dose of alcohol (.72 ml absolute alcohol/kg). Self-reports of dose (ml absolute alcohol/kg) on a typical social occasion, and hourly dose (which controlled for individual differences in the duration of these occasions) were found to decline linearly with age. Alcohol absorption and elimination rates in the sample were not significantly related to age. The Ponderal Index (an estimate of percentage of body water in body weight) was negatively correlated with age and with peak blood alcohol levels (BALs). Older subjects had proportionately less body water (i.e., a smaller volume for distribution of alcohol) and obtained higher BALs. When individual differences in BAL were controlled for, the amount of alcohol-induced impairment in task performance was still found to increase significantly with age. This evidence was considered to suggest that a reduction in the volume of distribution for alcohol and an intensified behavioral effect of alcohol may operate jointly to cause older persons to reduce their dose of alcohol on social drinking occasions.