Diet Quality Indices in the SUN Cohort: Observed Changes and Predictors of Changes in Scores Over a 10-Year Period

Abstract

BackgroundDietary quality indices (DQI) are widely used in nutritional epidemiology. However, how they might change over time in a Mediterranean population is not well understood. ObjectiveTo evaluate within-participant longitudinal changes in scores for nine a priori–defined DQIs: Fat Quality Index (FQI), Carbohydrate Quality Index (CQI), Pro-vegetarian Dietary Pattern (PVG), Mediterranean Diet Adherence Screener (MEDAS), Mediterranean Diet Score (MDS), Dietary Approaches to Stop Hypertension (DASH), Mediterranean-DASH Intervention for Neurodegenerative Delay Diet (MIND), Prime Diet Quality Score (PDQS) and Alternate Healthy Eating Index (AHEI-2010) in the “Seguimiento Universidad de Navarra” (SUN) cohort, a well-known Mediterranean cohort of university graduates, and to identify baseline predictors of improvement in MEDAS and AHEI-2010 after 10 years of follow-up. DesignIn this longitudinal cohort study, DQI scores were calculated based on responses from a validated semiquantitative food-frequency questionnaire (FFQ). Participants/settingSpanish university graduates enrolled in the SUN cohort before March 2008, who completed the 10-year FFQ and reported total dietary intake at baseline and after 10 years of follow-up, included 2,244 men and 3,271 women, whose mean age at baseline was 36.3 years (standard deviation [SD], 10.7). Main outcome measuresMain outcome measures were within-participant longitudinal changes for FQI, CQI, PVG, MEDAS, MDS, DASH, MIND, PDQS, and AHEI-2010. Statistical analyses performedAdjusted logistic regression models were used to evaluate within-participant longitudinal changes and to identify baseline predictors of improvements ≥10% in MEDAS and AHEI-2010 scores after 10 years of follow-up. ResultsThe comparison of the nine scores of DQI calculated at baseline and after 10 years of follow-up showed an improvement in all DQI scores except for PDQS. The greatest changes in DQIs were found for MEDAS (from 6.2 to 7.2, +22.9%) and MDS (from 4.3 to 4.4, +15.4%). The strongest predictors at baseline for ≥10% improvements in MEDAS or AHEI-2010 scores varied across indices. Being female, ≥35 years old, and more physically active at baseline were associated with improvement, whereas snacking between meals was associated with <10% improvements in both indices. ConclusionsIn this cohort, the changes in nine a priori-defined DQI scores suggested modest improvements in diet quality, in which MEDAS and MDS scores showed the largest improvements. Additional longitudinal studies, especially intervention trials with long follow-up, are warranted to establish the most appropriate DQIs to assess long-term changes in diet quality in adult populations.