Objectives: We sought to develop and evaluate the relative validity of a dietary diversity questionnaire (DDQ) that reflects food-group diversity, food variety, and micronutrient adequacy among New Zealand women.
Methods: A cross-sectional study included New Zealand women (Auckland based; ages 16-45 y, n = 101), completing a 7-d DDQ and 4-d weighed food record (reference method). The relative validity of the DDQ was evaluated by correlating nutritious and discretionary dietary diversity scores (DDSs; number of food groups) and food-variety scores (number of foods), calculated from both methods. The dietary mean adequacy ratio (MAR; micronutrient intakes relative to estimated average requirements) was calculated from the weighed food record and correlated to dietary diversity and food-variety scores from the DDQ to assess construct validity. Cross-tabulation was used to explore dietary diversity measures versus adequacy ratios. Significance was set at P < 0.05.
Results: The median (interquartile range) DDSs (maximum 25) from the DDQ-23 (21-23)-and the weighed food record-18 (17-19)-were significantly correlated (rs = 0.33, P < 0.001), as were the food-variety scores (maximum 237)-respectively, 75 (61-87) and 45 (37-52) (rs = 0.22, P < 0.03). A mean (± SD) MAR of 0.94 ± 0.04 suggested a near-adequate diet, but one-third of foods consumed were from discretionary sources. Nutritious DDS was significantly correlated with MAR for micronutrients (rs = 0.20, P ≤ 0.05). An inverse trend was observed between discretionary DDS and MAR.
Conclusions: The DDQ is a quick, low-burden tool for describing nutritious and discretionary dietary diversity reflecting micronutrient adequacy in high-income settings. It requires further validation across different time frames, population groups, and settings.
Keywords: Diet quality; Discretionary food; Food variety; Food-group diversity; High-income setting; Micronutrient adequacy; Nutritious food.
Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.