title: Reproducibility and validity of semi-quantitative food frequency questionnaire measuring dietary trans-fatty acids intake among Korean adults.
abstract: OBJECTIVE
  Compelling evidence indicates that consumption of trans-fatty acids (TFA) is associated with a wide range of diseases. However, few validated tools for TFA intake assessment are available in Korea. We aimed to validate a food frequency questionnaire (FFQ) estimating usual intake of TFA in Korean adults.
  
  
  METHODS
  Eighty-two healthy adults completed an FFQ with a 3-day diet record (3DDR), and 58 completed a second FFQ at a 1-month interval. To assess the reproducibility of the FFQ, we compared estimated TFA intakes from each FFQ. To assess the validity, we compared estimates from the FFQ with those from the 3DDR.
  
  
  RESULTS
  The FFQ was reproducible (Spearman r = 0.71) and provided modest correlations with the 3DDR (Spearman r = 0.38). After adjustment for total energy intake, the correlations increased (r = 0.45). Measurement-error correction also de-attenuated the correlations (r = 0.57). When quintiles of the FFQ and 3DDR were joint-classified, 9% on average were misclassified into extreme quintiles.
  
  
  CONCLUSIONS
  Our findings suggest that the developed FFQ is reproducible and reasonably valid in categorizing individuals according to TFA intakes among healthy young and middle aged adults in Korea.
authors: Department of Medicine, Seoul National University College of Medicine, Seoul, 110-799, Korea. ; Department of Family Medicine, Konkuk University Medical Center, Seoul, 143-729, Korea. ; Department of Family Medicine, Seoul National University Health Service Center, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea.
authors: Hee-Kyung
authors: HK
authors: Joh
authors: Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, 135-984, Korea.
authors: Seung-Won
authors: SW
authors: Oh
authors: Department of Nutrition, Konkuk University Medical Center Healthcare Center, Seoul, 143-729, Korea.
authors: Eun
authors: E
authors: Lee
keywords: Trans-fatty acid