Alcohol Experiences Viewed Mutoscopically: Newly Incident Drinking of Twelve- to Twenty-Five-Year-Olds in the United States, 2002-2013

Abstract

Objective: This study sought to discover recent age-specific and cohort-specific patterns of newly incident drinking of alcoholic beverages among young people in the United States, with identification of age at peak risk, cohort by cohort, and age by age.

Method: Data are from the U.S. National Surveys on Drug Use and Health 2002-2013, with 12 independent successive replications of nationally representative surveys (n ≈ 420,000 12- to 25-year-olds). Drinking was assessed via confidential computer-assisted self-interviews.

Results: Looking across age strata, we found rising age-specific drinking incidence rates across adolescence to a plateau at age 16-18 years and made a new discovery of a statistically robust and highly reproducible dip in incidence at age 19-20 years, followed by the major peak at age 21 years, with sharply reduced incidence thereafter. Evaluated using an epidemiological mutoscope view, individual cohorts showed a congruent pattern, with starting age held constant. A completely different pattern was seen in age-specific prevalence estimates that showed monotonic linear increases.

Conclusions: The novelty seen here, with multiple replications, is a set of clearly nonlinear, age-specific drinking incidence patterns not documented in prior studies. Evidence of noncongruent prevalence patterns is provided. We hope these simple examples will be useful in teaching the epidemiology of alcohol drinking.

Figure 1.

Reproduction of Table 1 in late Professor Wade Hampton Frost’s work on tuberculosis mortality that shows the seeds of the idea of a fine-grained mutoscope table (Frost, 1939). Estimates for prevalence of recently active drinking and cumulative incidence proportions are presented online in supplementary materials that accompany this article (Tables B and C). The estimated cumulative incidence proportion at age 12 years is larger than the other estimates because its numerator includes 12-year-olds with drinking onset in childhood (i.e., before the 12-month interval before the survey assessment date). These “very early childhood–onset drinkers” always appear in the numerators for each age-specific estimated “lifetime occurrence” proportion. This is not the case for the prevalence estimate of recently active drinking, for which the numerator consists of newly incident drinkers plus past-onset drinkers who continued to drink during the 12-month interval before the date of assessment. The numerators for the age-specific incidence rate estimates are limited to newly incident drinkers.

Figure 2.

Comparison of meta-analytic summary estimates for age-specific prevalence of drinking and estimated age-specific annual incidence. Data from United States National Surveys on Drug Use and Health, 2002–2013 (n ≈ 420,000 12- to 25-year-olds). CI = confidence interval.