Age at regular drinking, clinical course, and heritability of alcohol dependence in the San Francisco family study: a gender analysis

Abstract

We examined gender differences in age of onset, clinical course, and heritability of alcohol dependence in 2,524 adults participating in the University of California San Francisco (UCSF) family study of alcoholism. Men were significantly more likely than women to have initiated regular drinking during adolescence. Onset of regular drinking was not found to be heritable but was found to be significantly associated with a shorter time to onset of alcohol dependence. A high degree of similarity in the sequence of alcohol-related life events was found between men and women, however, men experienced alcohol dependence symptoms at a younger age and women had a more rapid clinical course. Women were found to have a higher heritability estimate for alcohol dependence (h(2)= .46) than men (h(2)= .32). These findings suggest that environmental factors influencing the initiation of regular drinking rather than genetic factors associated with dependence may in part underlie some of the gender differences seen in the prevalence of alcohol dependence in this population. (Am J Addict 2010;00:1-10).

Figure 1

The following graphs exhibit the cumulative survival rates between two groups of subjects: those who first began regular drinking under age (13,15,17,19,21,25) group (♦) versus those whose first alcohol consumption is over age (13,15,17,19,21,25) group (♢) respectively. The cumulative survival rate is the proportion of subjects within the group who survives (i.e. not developing alcohol dependence) at different points in time after the subjects’ first exposure to alcohol. The survival curves of the older alcohol consumption group (♢) are consistently above those of the younger group (♦), and their survival curves diverge farther and farther apart as time progresses. These graphs clearly indicate that subjects that consume alcohol at a later age are more likely to survive without alcohol dependence than those consume at an earlier age.