Simple descriptive statistics were used to summarize rates of alcohol use and problems in the 1989 twin cohort. Factor analysis of the 5 alcohol consumption measures, conducted in SAS (37) separately for men and women and for the 1989 twin and 1981 spouse samples, was used to generate a heaviness of consumption factor score for each individual. For joint analyses with categorical outcomes, factor scores were collapsed into a 7-level measure to ease computational burden.
