ASSOCIATION BETWEEN ALCOHOL-USE AND SMOKING IN ADOLESCENT AND YOUNG-ADULT TWINS - A BIVARIATE GENETIC-ANALYSIS

The association between alcohol use and smoking was examined in a larg e population-based sample of Dutch twins consisting of three age group s; young adolescent twins aged 12-14 years (n = 650 twin pairs), 15-16 -years-old adolescent twins (n = 705 twin pairs), and young adult twin s aged 17-25 years (n = 1266 twin pairs). For all three age groups, al cohol use and smoking were correlated (r = 0.5-0.6). Adolescents and y oung adults who smoked were more likely to drink alcohol than nonsmoke rs. The relation between alcohol use and smoking was also found within a twin pair; alcohol use in one twin was correlated with smoking in t he cotwin. This finding suggested that familial factors contribute to the association between alcohol and tobacco use. With a bivariate gene tic model, it was examined to what extent the comorbidity was due to g enetic and environmental factors that predispose to both alcohol use a nd smoking. The genetic analyses showed that the underlying factors th at influence alcohol and tobacco use and cause their association were different for adolescent and young adult twins. initiation of alcohol use and smoking in adolescents (aged 12-16 years) was substantially in fluenced by the same shared environmental features, Alcohol and tobacc o use in young adults were associated due to the same genetic risk fac tors.