Development and evaluation of a food frequency questionnaire for Vietnamese female immigrants in Korea: the Korean Genome and Epidemiology Study (KoGES)

The objectives of this study were to develop a food-frequency questionnaire (FFQ) for Vietnamese female immigrants in Korea and to evaluate the validity of the FFQ. A total of 80 food items were selected in developing the FFQ according to consumption frequency, the contribution of energy and other nutrients, and the cooking methods based on one-day 24 hour recall (24HR) from 918 Vietnamese female immigrants between November 2006 and November 2007. The FFQ was validated by comparison with 24HR of 425 Vietnamese female immigrants between November 2008 and August 2009. The absolute nutrient intake calculated from the FFQ was higher than that estimated by 24HR for most nutrients. The correlation coefficients between 24HR and FFQ ranged from 0.10 (vitamin C) - 0.36 (energy) for crude intake, 0.05 (vitamin E) - 0.32 (calcium) for per 1000 kcal, and 0.08 (zinc) - 0.34 (calcium) for energy-adjusted, respectively. More than 70% of subjects were classified into the same or adjacent agreement groups for nutrients other than fiber, sodium, vitamin A, vitamin C, and vitamin E, while less than 10% of subjects were classified into complete disagreement groups. We conclude that the FFQ appears to be an acceptable tool for estimating nutrient intake and dietary patterns of Vietnamese female immigrants in Korea. Future studies to validate the FFQ using various biomarkers or other dietary assessment methods are needed.