Common genetic and environmental vulnerability for alcohol and tobacco use in a volunteer sample of older female twins

Objective: A growing body of literature supports a shared genetic vulnerability underlying the use of alcohol and tobacco. We report patterns of genetic and environmental correlations for alcohol and tobacco use in a volunteer sample of older, white, female twins using three different levels of severitv for alcohol use and smoking. Method: A community-based sample of 1,926 female twins aged 50 to 96 was recruited through advertisements in a newsletter of the American Association of Retired Persons. Subjects were asked to rate alcohol and tobacco use over their lifetimes. Three levels of severity for alcohol use and smoking were coded: ever drank, weekly drinking, problem drinking ever smoked, daily smoking of one-half pack or more, daily smoking of at least one pack or more, Twin correlations for alcohol and tobacco use measures were fit using a structural equation-modeling package (Mx). Results: There were significant genetic correlations between problem drinking and ever smoking and using at least one-half pack per day. For problem drinking/ever smoking, R = 1.0 (95% CI: 0.32-1.0); for problem drinking/smoking at least one-half pack/day, R-g = 1.0 (95% Cl: 0.43-1.0). Conclusions: The shared genetic influence on alcohol use and smoking in women is clearest for those subjects with the highest severitv of alcohol use and problem drinking.