Validity and Reproducibility of a Culture-Specific Electronic Food Frequency Questionnaire: A Trinidad and Tobago Diet Assessment Study.

Nutritional epidemiologists use culture-specific food frequency questionnaires (FFQs) to assess the dietary intake of groups based on country, region or ethnic groups. This study aimed to validate a culture-specific semi-quantitative electronic Food Frequency Questionnaire (e-FFQ) to estimate food group intake in the adult population of Trinidad and Tobago. A 139-item semi-quantitative e-FFQ containing local dishes and street food was administered twice to adults 18 years and older and compared against four 1-day food records (FRs) using digital photographs, which served as the reference method. The validity and reproducibility of the e-FFQ food group intake estimates were determined using paired t-tests, bivariate correlations, and cross-classifications. Reproducibility correlations between the reported food group intakes in the first and repeat administration of the e-FFQ ranged from moderate (r = .44, P ≤ .0001) for sweetened beverages to high (r = .91 P ≤ .0001) for alcohol. The cross-classification agreements ranged from 70% (street food) to 92% (alcohol). Energy-adjusted deattenuated validity correlations between the e-FFQ and FR ranged from (r = .08) for water to (r = .81) for food from animal sources, with a mean validity correlation of .36. An average of 68% of the e-FFQ estimates was correctly classified within the ±1 quintile of the exact agreement with the FRs. Agreements between the e-FFQ and FRs ranged from 55% for street foods to 95% for water, all significant at P ≤ .0001. This study shows that the culture-specific e-FFQ is a valid tool for assessing and ranking food category intake estimates of the adult population living in Trinidad and Tobago.

Validity and Reproducibility of an Electronic Food Frequency Questionnaire in Argentinian Adults.

This study aimed to validate a semiquantitative electronic food frequency questionnaire (eFFQ) in estimating the intake of a comprehensive list of nutrients and bioactive compounds among adults from six regions of Argentina using multiple 24 h dietary recall (24HR) as a reference. A total of 163 adults completed two administrations of the eFFQ and four 24HRs. The paired t-test/Wilcoxon signed-rank test, Spearman/Pearson correlations, cross-classification, weighted kappa statistics, and Bland-Altman plots were employed to determine relative validity. To determine reproducibility, intraclass correlations (ICC), cross-classification, and weighted kappa statistics were calculated. For relative validity, crude correlations ranged from 0.15 to 0.57; energy adjustment and de-attenuation slightly improved most of these correlations. In cross-classification analysis, agreements within one quintile adjacent to exact agreement (EA ± 1) ranged from 52.2% to ~74%; extreme misclassifications were < 7%. For reproducibility, the crude ICC ranged from 0.29 to 0.85, showing moderate to good correlations for most nutrients. Cross-classification analysis showed agreement levels for the EA ± 1 quintile of 70.6% to 87.7%. Weighted kappa values ranged from 0.21 to 0.62. The results show that this eFFQ is relatively valid in ranking adults according to their nutrient intake and has an acceptable reproducibility, yet it slightly overestimates the intake of most nutrients.