Co-occurring risk factors for alcohol dependence and habitual smoking - Results from the collaborative study an the genetics of alcoholism

Smoking and alcohol dependence frequently occur together, and both behavior s are determined in part by genetic influences. The Collaborative Study on the Genetics of Alcoholism (COGA) which is investigating the genetic factor s contributing to alcohol dependence, also allows for analyses of the genet ic factors determining smoking. Using a sample comprised of alcoholics and their closest (i.e., first-degree) relatives as well as a community-based c ontrol sample, COGA investigators found that both alcohol dependence and ha bitual smoking were transmitted within families. This familial transmission resulted from both common and drug-specific influences, which likely inclu de genetic factors. Further genetic studies (i.e., candidate gene studies a nd genomic screening approaches) have identified several DNA regions that m ay contain genes that confer a susceptibility for alcoholism. Some of those genes also may contribute to the risk for habitual smoking.