RESUMO
Background: Nonquantitative list-based or open 24-h recalls (24-HRs) have been shown to overestimate the prevalence of Minimum Dietary Diversity for Women (MDD-W), as compared with direct quantitative observations. However, the main sources of error are unknown. Objectives: To assess the measurement agreement of proxy data collection methods for MDD-W, as compared with weighed food records (WFRs). Methods: Applying a noninferiority design, data were collected from 431 nonpregnant females in Ethiopia. MDD-W estimates from both proxy data collection methods were compared with the WFR prevalence by McNemar's chi-square tests, Cohen's Kappa, and receiver operator characteristic analyses. Ten-point food group diversity scores (FGDS) were compared by Bland-Altman plots, Wilcoxon matched-pairs tests, and weighted Kappa. Food group misclassifications were partitioned into errors related to respondent biases or the questionnaire development. Results: List-based and open 24-HRs overreported MDD-W by 8 and 4 percentage points, respectively, as compared with WFR (objective MDD-W prevalence: 8%). Furthermore, list-based 24-HRs overestimated FGDS by 0.4 points (limits of agreement [LOA]: -1.1, 2.0), whereas open 24-HRs led to a 0.3 point (LOA: -1.2, 1.7) overestimate. Food groups most likely to be misreported using proxy data collection methods were "pulses," "nuts and seeds," "dairy products," and "other fruits." Underreporting of consumption occurred among <4% of females for all food groups. Furthermore, respondent biases were the predominant cause of food group overreporting, except for the "pulses" and "other vegetables" food groups, where food items incorrectly included on the food list were the main source of errors. Conclusions: Food group consumption misclassifications by proxy data collection methods were mainly attributable to females overreporting consumption because of respondent biases or the criterion for foods to be counted, rather than the suboptimal development of the food list in Ethiopia. To obtain precise and accurate MDD-W estimates at the (sub)national level, rigorous context-specific food list development, questionnaire pilot testing, and enumerator training are recommended to mitigate identified biases.
RESUMO
Background: Adolescents' diets have been overlooked in nutrition information systems, interventions, and policies. The minimum dietary diversity for women (MDD-W) indicator has been validated to signal greater micronutrient adequacy among nonpregnant women from low- and middle-income countries, but there is limited evidence for valid food group thresholds among boys or nonpregnant nonlactating girls. Objective: To define a food group threshold that reflects minimum dietary diversity for adolescents. Methods: This multicountry study evaluated the test characteristics of a 10-point food group diversity score (FGDS)-underlying MDD-W-and food group thresholds to predict the micronutrient adequacy of diets from single 24-h recalls or food diaries (24-HRs) among 83,935 adolescents aged 10-19 y and repeated 24-HRs among 75,480 adolescents from upper-middle and high-income countries. Results: FGDS was lowest among adolescents in lower-middle countries (3.5 ± 1.1) and greatest in high-income countries (5.4 ± 1.3 points). Using single 24-HRs, 1-point increments in FGDS performed identically to predict a higher mean adequacy ratio among boys and girls (5.1 percentage points; 95% confidence interval: 5.0, 5.2; P < 0.001). MDD-W (i.e., ≥5 food groups) performed well in predicting a mean adequacy ratio of >0.60 among adolescents from upper-middle and high-income countries, whereas a ≥4 food group cutoff showed a superior balance between sensitivity, specificity, and percentage correctly classified in low (only girls) and lower-middle-income countries (boys and girls). In contrast, using repeated 24-HRs, the mean probability of adequacy levels among adolescents were too high and homogeneous (i.e., all mean probability of adequacies > 0.60) to define an optimal food group threshold. Conclusions: MDD-W can be extended to boys and girls aged 10-19 y from upper-middle and high-income countries. Furthermore, an adapted indicator using a ≥4 food group threshold signals higher micronutrient adequacy in low and lower-middle-income countries. Food group cutoffs to predict the micronutrient adequacy of usual intakes should be validated using repeated 24-HRs in populations where a lower proportion of adolescents meet mean dietary requirements.