Predictors of Follow-Up Engagement in an Adolescent Alcohol Longitudinal Cohort

Attrition can bias longitudinal findings, including those on alcohol use. We examined predictors of follow-up engagement in a multi-site neuroimaging cohort of youth.

Data were drawn from the first nine annual waves of the National Consortium on Alcohol and Neurodevelopment in Adolescence (NCANDA), which recruited 831 participants aged 12-21 years in 2013-2014 (52% female). Follow-up engagement was modeled as the total number of completed follow-up visits (0-9, excluding baseline) using Poisson regression with multiple imputation and family-cluster-robust standard errors. Secondary analyses examined categorical engagement levels. Primary predictors included exceeding age- and sex-specific baseline alcohol use thresholds, externalizing symptoms, race, and demographic and family factors.

Overall engagement was high, with participants completing an average of approximately 9 of 10 possible visits. In Poisson models, exceeding baseline alcohol use thresholds was associated with a modest reduction in follow-up visits, although this did not reach statistical significance (IRR = 0.940, 95% CI: 0.881-1.004, p = .064). Externalizing symptoms were not significantly associated with engagement (IRR = 1.001, 95% CI: 0.998-1.003, p = .647). Sibling co-enrollment was associated with greater engagement (IRR = 1.058, 95% CI: 1.021-1.097, p = .002), while other factors showed small or non-significant associations.

Follow-up engagement was generally high across adolescence into young adulthood. Exceeding baseline alcohol use thresholds showed a modest association with reduced engagement, although not statistically significant in the count model. Externalizing symptoms were not associated with engagement. Categorical analyses suggested a stronger association between exceeding baseline alcohol use thresholds and lower engagement groups. These findings may help identify participants who could benefit from additional engagement efforts.