A twin study of ethanol metabolism.

Blood alcohol measurements were obtained for 206 pairs o f twins who had ingested a standard dose of alcohol (0.75g/kg body weight) and repeat measurements were obtained for 40 of these pairs on a second occasion. The repeatability o f the peak blood alcohot concentration (BAC) was 0.66, that o f the rate of elimination was 0.39, and that o f the time to peak BAC was 0.27. Only a small portion of the nonrepeatable variance could be explained by measurement error or drinking experience. It is concluded that short-term environmental factors exercise considerable influence on alcohol metabolism, particularly in the absorption phase. All o f the repeatable variance in peak BAC and rate o f elimination was due to genetic factors. Only a small proportion of any of the genetic variance could be explained by individual differences in weight, adiposity, or lung function. Likewise, these three factors were unable to account for the fact that females had higher BACs than males during both absorption and elimination.