Alcohol consumption indices of genetic risk for alcohol dependence.
BACKGROUND
Previous research has reported a significant genetic correlation between heaviness of alcohol consumption and alcohol dependence (AD), but this association might be driven by the influence of AD on consumption rather than the reverse. We test the genetic overlap between AD symptoms and a heaviness of consumption measure among individuals who do not have AD. A high genetic correlation between these measures would suggest that a continuous measure of consumption may have a useful role in the discovery of genes contributing to dependence risk.


METHODS
Factor analysis of five alcohol use measures was used to create a measure of heaviness of alcohol consumption. Quantitative genetic analyses of interview data from the 1989 Australian Twin Panel (n = 6257 individuals; M = 29.9 years) assessed the genetic overlap between heaviness of consumption, DSM-IV AD symptoms, DSM-IV AD symptom clustering, and DSM-IV alcohol abuse.


RESULTS
Genetic influences accounted for 30%-51% of the variance in the alcohol measures and genetic correlations were .90 or higher for all measures, with the correlation between consumption and dependence symptoms among nondependent individuals estimated at .97 (95% confidence interval: .80-1.00).


CONCLUSIONS
Heaviness of consumption and AD symptoms have a high degree of genetic overlap even among nondependent individuals in the general population, implying that genetic influences on dependence risk in the general population are acting to a considerable degree through heaviness of use and that quantitative measures of consumption will likely have a useful role in the identification of genes contributing to AD.
Grant
Julia D
JD
Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA. grantj@psychiatry.wustl.edu
Agrawal
Arpana
A
Bucholz
Kathleen K
KK
Madden
Pamela A F
PA
Pergadia
Michele L
ML
Nelson
Elliot C
EC
Lynskey
Michael T
MT
Todd
Richard D
RD
Todorov
Alexandre A
AA
Hansell
Narelle K
NK
Whitfield
John B
JB
Martin
Nicholas G
NG
Heath
Andrew C
AC
D000328:Adult; D000428:Alcohol Drinking / Q000235:genetics*; D000437:Alcoholism / Q000175:diagnosis / Q000235:genetics*; D004200:Diseases in Twins / Q000235:genetics; D005163:Factor Analysis, Statistical; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008957:Models, Genetic; D019655:Quantitative Trait, Heritable; D012737:Sex Factors; D018454:Spouses / Q000523:psychology; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology