Heritability of Usual Alcohol Intoxication and Hangover in Male Twins: The NAS-NRC Twin Registry

Alcohol consumption is influenced by heritable factors. The genetic influence on usual high-density drinking, including alcohol intoxication and hangover, is unknown. We aim to estimate the heritability of usual high-density drinking. Methods: A total of 13,511 male twins in this cross-sectional study were included from the National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry. Data on the frequency of alcohol intoxication and alcohol hangover over the past year, that is, usual high-density drinking (phenotypes), were collected through a self-administered questionnaire when twins were middle-aged in 1972. Structural equation modeling was used to estimate the variance components of phenotypes. Results: The mean of the frequency of usual high-density drinking in the entire twin population was 0.16 times per month for intoxication and 0.18 times per month for hangover. The heritability of usual alcohol intoxication was 50.7% (95% confidence interval [CI] 46.2 to 55.0) before and 49.9% (95% CI 45.3 to 54.2) after the body mass index (BMI) adjustment. The heritability of usual hangover was 55.4% (95% CI 51.2 to 58.6) before and 54.8% (95% CI 50.6 to 58.8) after adjustment for BMI. Unshared environmental factors between co-twins explained the remaining variance in alcohol intoxication and in hangover. Conclusions: Both genetic and unshared environmental factors have important influences on usual alcohol intoxication and hangover. These findings are important in understanding the occurrence of and developing interventions for usual high-density drinking.