title: A suggested approach for imputation of missing dietary data for young children in daycare.
abstract: BACKGROUND
  Parent-reported 24-h diet recalls are an accepted method of estimating intake in young children. However, many children eat while at childcare making accurate proxy reports by parents difficult.
  
  
  OBJECTIVE
  The goal of this study was to demonstrate a method to impute missing weekday lunch and daytime snack nutrient data for daycare children and to explore the concurrent predictive and criterion validity of the method.
  
  
  METHODS
  Data were from children aged 2-5 years in the My Parenting SOS project (n=308; 870 24-h diet recalls). Mixed models were used to simultaneously predict breakfast, dinner, and evening snacks (B+D+ES); lunch; and daytime snacks for all children after adjusting for age, sex, and body mass index (BMI). From these models, we imputed the missing weekday daycare lunches by interpolation using the mean lunch to B+D+ES [L/(B+D+ES)] ratio among non-daycare children on weekdays and the L/(B+D+ES) ratio for all children on weekends. Daytime snack data were used to impute snacks.
  
  
  RESULTS
  The reported mean (± standard deviation) weekday intake was lower for daycare children [725 (±324) kcal] compared to non-daycare children [1,048 (±463) kcal]. Weekend intake for all children was 1,173 (±427) kcal. After imputation, weekday caloric intake for daycare children was 1,230 (±409) kcal. Daily intakes that included imputed data were associated with age and sex but not with BMI.
  
  
  CONCLUSIONS
  This work indicates that imputation is a promising method for improving the precision of daily nutrient data from young children.
authors.affiliation: Department of Nutrition, University of North Carolina, Chapel Hill, NC, USA.|Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA; June_Stevens@unc.edu.
authors.forename: June
authors.initials: J
authors.lastname: Stevens
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Fang-Shu
authors.initials: FS
authors.lastname: Ou
authors.affiliation: Department of Nutrition, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Kimberly P
authors.initials: KP
authors.lastname: Truesdale
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Donglin
authors.initials: D
authors.lastname: Zeng
authors.affiliation: Center for Health Promotion and Disease Prevention, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Amber E
authors.initials: AE
authors.lastname: Vaughn
authors.affiliation: Clinical Application and Prevention Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Pratt
authors.affiliation: Department of Nutrition, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Dianne S
authors.initials: DS
authors.lastname: Ward
keywords: children; daycare; methods; missing data; nutrition