Adaptation, validation and reproducibility of a short FFQ to assess food group intake in the population resident in the Basque country (Spain).

objectiveTo adapt a short FFQ (SFFQ) and evaluate its relative validity and reproducibility to assess food group intake in a population resident in the Basque Country. Moreover, the possible influence of associated variables (such as education level) on its validity and reproducibility was determined.

designNine-day 24-h recalls (24HR) were used as a reference to explore validity over the course of 1 year. The degree of misclassification in the SFFQ was evaluated by a contingency table of quartiles and by Bland-Altman plots comparing SFFQ2 and 24HR. SFFQ was administered twice to explore reproducibility at 1 year.

settingBasque Autonomous Community.

participantsAdults aged ≥21 years (n 99). The sample was randomly selected and representative of the target population.

resultsFor validity, statistically significant correlations were observed for more than half of the food groups, with the lowest correlations (r or ρ) for fat (-0·008) and the highest for other foods (0·963). The mean percentage of the subjects' food intake that was classified into the same or adjacent quartile in both methods was 75·2 %. Reproducibility was explored by the correlation coefficient and ranged from 0·201 to 0·809, and 82·6 % of participants were in the same or adjacent quartile in both SFFQ. The associated variables did not seem to influence the validity and reproducibility of the SFFQ.

conclusionsAn adapted SFFQ presented good reproducibility and validity for measuring most food groups in the target population, and these results did not seem to be influenced by the associated variables.