Drinking course through midlife based on diagnostic versus quantity-frequency indices.

BACKGROUND: Prior efforts to examine the course of drinking from onset to midlife have been limited to analyses of year-to-year changes in alcohol dependence (AD). The current investigation sought to examine the course of drinking over this time frame using consumption-based measures of drinking and evaluate the degree of comparability in trajectories estimated from diagnostic and quantity-frequency data.
METHODS: Participants included 420 men with a lifetime history of AD who were drawn from the Vietnam Era Twin Registry and administered the Lifetime Drinking History, which provided person-year (retrospective) data on patterns of consumption and diagnostic symptoms from drinking onset to participants' current age. Consumption-based data were aggregated into age categories that ranged from "up to age 20" to "ages 54 to 56" and analyzed separately as a dichotomous measure of "heavy drinking (HD)" and continuous quantity-frequency index (QFI) scores.
RESULTS: Using latent growth mixture modeling, trajectories based on the HD measure were moderately concordant with those based on changes in AD that were previously identified in this sample, whereas trajectories based on QFI scores were only weakly related to those based on AD diagnoses. Moreover, examination of the degree of concordance between AD- and QFI-derived trajectories revealed that measures of consumption (and potentially other continuous indices of drinking) may qualify past interpretations of various developmental trajectories that have been discussed in the alcoholism typology literature (particularly "Late Onset" alcoholism).
CONCLUSIONS: Collectively, the findings highlight the importance of integrating repeated measures of alcohol consumption in future efforts to describe the course of drinking across the life span.