title: Validation of a new food frequency questionnaire for assessment of calcium and vitamin d intake in korean women.
abstract: BACKGROUND
  Validated simple calcium questionnaires are available to assess the intake of calcium and vitamin D in western countries, but they are not appropriate for Koreans since dairy products are not the major source of calcium and vitamin D in Korea. Thus, the objective of the present study was to develop and validate a simple and easy food frequency questionnaire (FFQ) of calcium and vitamin D for Korean.
  
  
  METHODS
  Two hundred and fifty-six women were asked to complete the validated FFQ used by the Korean National Health and Nutrition Examination Survey (KNHANES) and a newly developed FFQ, the Korean Calcium Assessment Tool (KCAT), which contain the 7 food groups with 24 categories of 45 food items that are consumed frequently by Koreans.
  
  
  RESULTS
  Calcium intake was not significantly different between the two methods; Pearson's correlation coefficient of 0.98 indicated a positive correlation, and Cohen's kappa coefficient of 0.78 indicated the subjects were correctly classified. Bland-Altman plot also showed that the mean differences of the calcium intake as assessed by the two methods were in high agreement. However, the vitamin D intake assessed by KCAT was significantly higher than that assessed by the FFQ used in KNHANES. The vitamin D intakes as assessed by the two methods were positively correlated but the two methods were in moderate agreement.
  
  
  CONCLUSIONS
  The results suggested that the newly developed KCAT was a valid tool for assessing the calcium intake in Korean women, but it might overestimate the vitamin D intake.
authors: Department of Food and Nutrition, Hanyang University, Seoul, Korea.
authors: Yongsoon
authors: Y
authors: Park
authors: Department of Food and Nutrition, Hanyang University, Seoul, Korea.
authors: Sang-Hee
authors: SH
authors: Kim
authors: Department of Obstetrics and Gynecology, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors: Yong-Taek
authors: YT
authors: Lim
authors: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, Seoul, Korea.
authors: Yong-Chan
authors: YC
authors: Ha
authors: Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors: Jae-Suk
authors: JS
authors: Chang
authors: Department of Orthopaedic Surgery, College of Medicine, Hanyang University, Seoul, Korea.
authors: I-Seok
authors: IS
authors: Kim
authors: Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Yong-Ki
authors: YK
authors: Min
authors: Department of Endocrinology and Metabolism, Kyung Hee University School of Medicine, Kyung Hee Hospital at Gangdong, Seoul, Korea.
authors: Ho-Yeon
authors: HY
authors: Chung
keywords: Calcium; Diet surveys; Korean women; Questionnaires; Vitamin D