Reproducibility of an FFQ validated in Spain

Area of Science:

• Nutritional epidemiology
• Dietary assessment methods

Background:

• The Seguimiento Universidad de Navarra (SUN) project utilizes a semi-quantitative Food Frequency Questionnaire (FFQ) for dietary intake assessment.
• Evaluating the reproducibility of dietary assessment tools is crucial for ensuring the reliability of epidemiological studies.

Purpose of the Study:

• To assess the reproducibility of a semi-quantitative FFQ within the SUN project.
• To determine the impact of the time interval between questionnaire administrations on reproducibility.

Main Methods:

• A subsample of 326 participants from the SUN project completed the FFQ twice.
• The time interval between the two administrations was either less than or greater than one year.
• Pearson correlation coefficients and quintile misclassification were used to evaluate reproducibility.
• Energy adjustment and correction for within-person variability were applied.

Main Results:

• High corrected correlations were observed for polyunsaturated fatty acids (PUFA) when the interval was less than one year (r = 0.99).
• Olive oil showed the highest corrected correlation when the interval exceeded one year (r = 0.99).
• Cereals, fish/seafood, and n-3 fatty acids had the highest gross misclassification (7.6%), while alcoholic beverages had the highest reasonable classification (86.4%).

Conclusions:

• The FFQ demonstrates acceptable reproducibility for repeated administrations within a one-year period.
• A longer interval between FFQ administrations (>1 year) leads to decreased reproducibility.
• The Spanish FFQ is considered a valid and reproducible tool for nutritional epidemiology research.