Comparison of validity of the Food Frequency Questionnaire and the Diet History Questionnaire for assessment of energy and nutrients intakes in an Iranian population.

BACKGROUND

Dietary intakes are important for development and prevention of chronic disease. The Food Frequency Questionnaire (FFQ) has been suggested as an acceptable feasible method for assessing the association of dietary intake and disease. However, FFQs are sensitive to dietary habits and culture and should be valid in the study population.

AIMS

We investigated the validity of the Diet History Questionnaire (DHQ) and the Food Frequency Questionnaire in healthy Iranians.

METHODS

Participants were healthy relatives of cancer patients in the Cancer Institute of Iran. They participated in face-to-face interviews. We took telephone based 24-hour recalls every 2 months over a 1-year period. Assuming the mean intakes of 24-hour recalls as the gold standard, we estimated Pearson correlation coefficients to measure the reliability of the FFQ and the DHQ. We investigated how the FFQ or DHQ categorized individuals in different intake groups comparing with the 24-hour recalls.

RESULTS

Overall, 102 subjects took part in our study. Deattenuated Spearman correlations were ≥ 0.5 for energy, carbohydrate, protein, carotene, niacin, folate, vitamin B, biotin, vitamin C, iron, zinc and selenium in both DHQ and FFQ. Level of agreement with 24-hour recall in classifying individuals into different categories of intakes ranged from 0.81 for riboflavin and carotene to 0.92 for carbohydrate and zinc in the DHQ and from 0.75 for riboflavin to 0.96 for carbohydrate in the FFQ.

CONCLUSIONS

Both DHQ and FFQ were valid in assessing most nutrient intakes and classifying individuals in different categories of intakes in the Iranian population.