Factors Associated With Changes in Fruit Intake During Young Adulthood: A Classification and Regression Tree Analysis of Longitudinal Data
To examine whether distinct participant groupings for changes in fruit intake (FI) levels between ages 23 and 31 years are identifiable based on both time-varying and time-invariant sociodemographic and behavioral variables.Methods:
Data were derived from the National Longitudinal Survey of Youth–1997, US. Change in FI frequency constituted the dependent variable. For 21 variables, changes and averages in 2007–2011 were calculated. Classification and regression tree analysis was conducted using Generalized, Unbiased, Interaction Detection, and Estimation software.Results:
Analysis isolated 5 variables (changes in smoking, drinking alcohol, and television viewing, plus 5-year mean of income-to-poverty ratio and computer use) and associated cutoff values to identify 7 groups of participants with differing degrees of FI change.Conclusions and Implications:
Multiple groupings existed within upper social strata; a majority maintained healthy behaviors whereas some adopted substance use stress-coping mechanisms. Some low-income individuals demonstrated a capacity to adopt healthy behaviors. Dietary interventions could identify behavioral clustering, with emphasis on drinking, smoking, and screen time.