Elaborating the association of age at first drink with risky drinking: results from a cross-sectional survey

Objective: An association between early drinking onset and subsequent heavy drinking has been established, but interpretation is problematic: is the onset of drinking or of intoxication important; is early onset a marker for vulnerability or a causal risk factor; what role does recall bias play? We (1) compare the associations of onset indicators with subsequent risky drinking, (2) assess whether drinking onset has a stronger association with subsequent risky drinking than relative onset (deviation from cohort's median), and (3) study recall bias by examining within-cohort temporal changes in reported ages of drinking onset. Method: The Finnish Drinking Habits Survey, a cross-sectional general population survey of 15-79-year-old Finns collected in 2016. Additionally, the four previous survey waves from 1984 to 2008 were used. Risky drinking was defined using the Alcohol Use Disorders Identification Test (AUDIT), and the age of first drink (AFD) and of intoxication (AFI) were obtained by retrospective recall. Results: All three indicators showed statistically significant associations with AUDIT, but AFI had the strongest association. Absolute age of onset had a slightly stronger association with AUDIT than relative age of onset. Recall bias of AFD was found for each birth cohort, as the reported AFD within each cohort increased over time. Conclusions: Onset of intoxication has stronger association with risky drinking than the onset of drinking. No gain was seen in measuring relative rather than absolute age of onset, which suggests that age of onset is not merely a marker of vulnerability to risky drinking.