Development and validation of a food frequency questionnaire for Korean Americans

A food frequency questionnaire for Korean Americans (KFFQ) was developed by modifying Block's Health Habits and History Questionnaire (HHHQ). The final KFFQ contained 118 food items taking into account culturally specific dietary patterns. Validation of the KFFQ was conducted to compare the nutrient intakes assessed by the KFFQ against those measured by seven-day dietary records in 73 Korean Americans. The mean nutrient values from the KFFQ differed at most by 25% from those of the dietary records with the exception of vitamin A, and 70% of the nutrients (16 out of 23 nutrients) were within 15%. Adjusted Spearman rank-order correlation coefficients for nutrients ranged between 0.45 and 0.84. The overall degree of agreement between the KFFQ and the dietary records was 68% with a range 56% to 79%. This validation study indicates that the KFFQ gives reasonably accurate estimates of the usual dietary intakes among the study population. The results also verify that it is possible to use a FFQ that is both culturally specific and comprehensive with the benefit of being easy to self-administer. This high degree of correlation between the KFFQ and the dietary records demonstrates that the KFFQ provides an easier yet accurate method in large-scale epidemiological studies of relationships between nutrition intakes and diseases in Korean Americans.