Validation and reproducibility of food frequency questionnaire for Korean genome epidemiologic study

Abstract

Objective: To evaluate validity and reliability of the food-frequency questionnaire (FFQ) developed for the Korean Genome Epidemiologic Study (KoGES). Methods: FFQ was administered twice at 1-year interval (first FFQ (FFQ1) at the beginning and second FFQ (FFQ2) at the end of the study) and diet records (DRs) were collected for 3 days during each of the four seasons from December 2002 to May 2004 for those who attended the health examination center. At the end of the study period, we collected the 12-day DRs of 124 participants. The nutrient intakes from the DRs were compared with both FFQ1 and FFQ2. Results: The intakes of energy and some nutrients estimated from FFQ1 and FFQ2 were different from those assessed by the DRs. Especially, the consumption of carbohydrates was higher in FFQ1 and FFQ2 than in the DRs. The de-attenuated, age, sex and energy intake adjusted correlation coefficients between the FFQ2 and the 12-day DRs in Korean population ranged between 0.23 (Vitamin A) and 0.64 (carbohydrate). The median for all nutrients was 0.39. The correlations were similar when we compared nutrient densities of both methods. Joint classification of calorie-adjusted nutrient intakes assessed by FFQ2 and 12-day DRs by quartile ranged from 25.8% (vitamin A) to 39.5% (carbohydrate, iron) for exact concordance. Except vitamin A, the proportion of subjects classified into distant quartile was less than 7% in all nutrients. The median of correlations between the two FFQs 1 year apart were 0.45 for all nutrient intakes and 0.39 for nutrient densities. Conclusions: We conclude that the FFQ we have developed appears to be an acceptable tool for assessing the nutrient intakes in this population. Further studies for calibration of the FFQ collected from multicenters participating in the KoGES are needed.

Validation of a quantitative FFQ for the Barbados National Cancer Study

“…Comparing the two dietary assessment methods used in the present study, the average level of agreement between the quartiles of absolute nutrient intake was similar to or higher than that reported by studies on Korean (13) , American (14) and German (15) populations. The mean proportion of classification into the same quartile for energy and macronutrients was higher in the present study (40 %) than in the Korean (37 %), American (38 %) and German (32 %) -Adjusted for day-to-day variation in the food diary data.…”

Validation of the Food Frequency Questionnaire Used to Assess the Association between Dietary Habits and Cardiovascular Risk Factors in the NESCAV Study

“…Except for protein and cholesterol, results were similar or better than the correlations found in comparable studies [13,21,29]. Some studies which used 7-day dietary records obtained better or similar correlation coefficients [13,30] and those which used 3-day dietary records obtained lower or similar results [31]. Although, the validation of the original Canadian version of the FFQ [9] showed good correlation coefficients for protein (r=0.75) and cholesterol (r=0.74), correlations obtained from the modified FFQ were not significant.…”

“…According to the literature [32], 3 days of recordings were reasonable because declining accuracy of recording with increasing fatigue and boredom have been noticed with longer records. However, a higher number of record days, spread over the whole year would have been more optimal as reference method, since this could take into account seasonal variation as well [31].…”

Diet quality scores and oxidative stress in Korean adults

“…For food items with different seasonal availability, the subjects were asked to give the period that they were consumed among four categories: three, six, nine or 12 months. The procedures for development and validation of the FFQ were reported in detail elsewhere (Ahn et al, 2003(Ahn et al, , 2007. Intake information from the FFQ was used to calculate RFS and aMDS.…”