Abstract
BACKGROUND: Several lines of evidence suggest that the lifetime prevalence of alcohol dependence among women has increased in recent decades, but has not risen significantly for men. Early age at onset of drinking (AOD) is strongly correlated with risk for alcohol dependence and there is evidence that mean AOD has also decreased, particularly for women. The present report sought to confirm the trends in AOD and to determine the extent to which they might account for secular trends in alcohol dependence. METHODS: Repeated cross-sectional analyses of data from 2 large, national epidemiological surveys were conducted to enable estimates of cross-cohort differences while controlling for age-related factors. Regression analyses were used to compute risk for alcohol dependence associated with birth cohort membership, before and after inclusion of AOD as a covariate. RESULTS: Both men and women born between 1944 and 1963 had earlier ages of onset for drinking than did the earliest birth cohort analyzed (1934-43). However, the net decrease in AOD was twice as large for women (3.2 years) than that for men (1.6 years). After adjusting for AOD, differences in lifetime prevalence between different birth cohorts of women were rendered nonsignificant, indicating that AOD accounts for a substantial portion of change in the lifetime prevalence of alcohol dependence. CONCLUSIONS: These results suggest that a decrease in AOD accounts for much of the increase in lifetime alcohol dependence among women. AOD is likely to be an indicator of dynamic, and therefore modifiable risk behaviors impacting risk for alcohol dependence.