Behavioral and Sociodemographic Correlates of Overall Diet Quality Over 4 Years in a National Cohort of U.S. Emerging Adults
Authors: LIPSKY LEAH M , Nansel Tonja R , Haynie Denise , Liu Danping , Li Kaigang , Pratt Charlotte , Iannotti Ronald J , Simons‐Morton Bruce 
Published: November 2023

This study examined trajectories of 5 diet quality indices‐ Healthy Eating Index‐2010 (HEI), Whole Plant Foods Density (WPF), Nutrient Rich Foods Score 9.3 (NRF), Dietary Variety (DV), and Empty Calories (EC, %kcal from discretionary solid fat, added sugar and alcohol), and investigated sociodemographic and behavioral correlates over the first 4 years of the NEXT Plus Study, an ongoing national cohort of US youth (n=517) followed prospectively. Subjects in 10th grade were enrolled in 2010 (54% female, 45% White, 49% overweight/obese, mean±SE baseline age=16.5±.0y). Diet quality indices were calculated from three 24‐hour dietary recalls completed annually. Baseline weight status was calculated from measured height and weight. Subjects wore accelerometers for 4–7 days annually to provide mean daily metabolic equivalents (MET) and duration of sedentary behavior (SED). Annual surveys queried meal practices and media use; Family Affluence Score (FAS) and parent educational attainment were assessed at baseline. Linear generalized estimating equations (GEE) examined diet quality trajectories over Y1 to Y4. Associations of time‐varying diet quality with baseline sociodemographics were estimated using a GEE model adjusted for time and baseline weight status. Associations of time‐varying diet quality with time‐varying behavioral factors were examined in separate GEE models adjusted for baseline weight status and sociodemographics. Multiple imputation was used for missing data. Baseline mean±SE HEI=44.0±.5, WPF=1.2±.04, NRF=13.1±.6, DV=5.5±.1, and EC=35.4%±0.5% (689.2±17.7 empty kcal/day). Minor improvements were observed in Y4 HEI (year 4 mean±SE =46.0±.7), WPF (1.6±.1), NRF (15.4±.7) and EC (32.7%±.6%, ~595±18.6 kcal/day). Hispanic vs. White subjects had higher time‐varying HEI (p<.001) and NRF (p<.001) and lower EC (p=.001). FAS was positively associated with DV (p=.008) and EC (p=.02). Breakfast was associated with higher HEI, WPF, NRF and DV (all p<.001), and inversely with EC (p=.01). Family meals were associated with higher HEI, WPF and DV (all p<.01). Fast food was associated inversely with HEI, WPF, NRF, and DV, and positively with EC (all p<.01). TV meals were inversely associated with HEI, WPF and NRF (all p<.01). TV viewing and social networking were associated inversely with HEI (p<.01), WPF (p<.001), NRF (p<.05) and variety (p<.05), and positively with EC (p<.01). Gaming was positively associated with EC (p=.03). MET was positively associated with WPF and NRF (p<.05), but sedentary time was not associated with diet quality. Diet quality of US emerging adults remained suboptimal, but improved marginally over the study period. Meal contexts and media use may represent important intervention targets. There is substantial room for improvement in intake of empty calories in all subgroups.Support or Funding InformationThis research (contract number HHSN267200800009C) was supported by the intramural research program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development. the National Heart, Lung and Blood Institute, the National Institute on Alcohol Abuse and Alcoholism, and Maternal and Child Health Bureau of the Health Resources and Services Administration, with supplemental support from the National Institute on Drug Abuse.