Assessment of the Dutch Healthy Diet index 2015 in the Lifelines cohort study at baseline

BACKGROUND: Dietary indices are useful measures to investigate associations between dietary intake and disease development. The Dutch Healthy Diet index 2015 (DHD2015-index), a measure of diet quality, assesses adherence to the 2015 Dutch dietary guidelines. We assessed the DHD2015-index in the Lifelines cohort study, and compared calculations from basic and detailed dietary intake data. This article replaces the retracted article that was published on 16 May 2022. METHODS: Dietary intake was assessed with a specially developed Food Frequency Questionnaire (FFQ) called Flower-FFQ, consisting of one main questionnaire (heart-FFQ) on major food groups and three complementary questionnaires (petal-FFQs) on detailed food types. The DHD2015-index was assessed using data from the total Flower-FFQ (n=56,982) and using data from the heart-FFQ only (n=129,030). Agreement between indices was assessed with correlation and cross-classification. RESULTS: Median (25th–75th percentile) DHD2015-index scores were 75 (65–85) for men and 81 (70–91) for women based on the Flower-FFQ, and 68 (58–77) for men and 73 (63–82) for women based on the heart-FFQ. Kendall's tau-b correlation between the two scores was 0.67 for men and 0.66 for women. Cross-classification into quartiles showed 59–60% classified in the same quartile, 36–37% in the adjacent, and 4% in the non-adjacent quartile. CONCLUSION: Dietary data from the Flower-FFQ provide the most optimal information to assess the DHD2015-index. However, the DHD2015-index from the heart-FFQ showed good agreement with the index from the Flower-FFQ for ranking participants by diet quality and can be used when Flower-FFQ-based indices are not available.

A. Mireille Baart, Elske M. Brouwer-Brolsma, Hanne B. T. de Jong, Jeanne H. M. de Vries, Edith J. M. Feskens