title: Comparison of weighed food record procedures for the reference methods in two validation studies of food frequency questionnaires.
abstract: BACKGROUND
  Although open-ended dietary assessment methods, such as weighed food records (WFRs), are generally considered to be comparable, differences between procedures may influence outcome when WFRs are conducted independently. In this paper, we assess the procedures of WFRs in two studies to describe their dietary assessment procedures and compare the subsequent outcomes.
  
  
  METHODS
  WFRs of 12 days (3 days for four seasons) were conducted as reference methods for intake data, in accordance with the study protocol, among a subsample of participants of two large cohort studies. We compared the WFR procedures descriptively. We also compared some dietary intake variables, such as the frequency of foods and dishes and contributing foods, to determine whether there were differences in the portion size distribution and intra- and inter-individual variation in nutrient intakes caused by the difference in procedures.
  
  
  RESULTS
  General procedures of the dietary records were conducted in accordance with the National Health and Nutrition Survey and were the same for both studies. Differences were seen in 1) selection of multiple days (non-consecutive days versus consecutive days); and 2) survey sheet recording method (individual versus family participation). However, the foods contributing to intake of energy and selected nutrients, the portion size distribution, and intra- and inter-individual variation in nutrient intakes were similar between the two studies.
  
  
  CONCLUSIONS
  Our comparison of WFR procedures in two independent studies revealed several differences. Notwithstanding these procedural differences, however, the subsequent outcomes were similar.
authors.affiliation: Faculty of Nutritional Science, Sagami Women's University, Kanagawa, Japan; Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Ishii
authors.affiliation: Faculty of Nutritional Science, Sagami Women's University, Kanagawa, Japan; Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan. Electronic address: ishihara_junko@isc.sagami-wu.ac.jp.
authors.forename: Junko
authors.initials: J
authors.lastname: Ishihara
authors.affiliation: Faculty Division of Human Life and Environmental Sciences, Research Group of Food Science and Nutrition, Nara Women's University, Nara, Japan; Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Ribeka
authors.initials: R
authors.lastname: Takachi
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Yurie
authors.initials: Y
authors.lastname: Shinozawa
authors.affiliation: Department of Food Science and Nutrition, Faculty of Human Life and Environmental Sciences, Nagoya Women's University, Aichi, Japan.
authors.forename: Nahomi
authors.initials: N
authors.lastname: Imaeda
authors.affiliation: Department of Health and Nutrition, School of Health and Human Life, Nagoya Bunri University, Aichi, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Goto
authors.affiliation: Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakai
authors.affiliation: Department of Cardiology, Hiraka General Hospital, Akita, Japan.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Public Health, Department of Social and Environmental Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan.
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Iso
authors.affiliation: Department of Community Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Department of Health Promotion Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Junta
authors.initials: J
authors.lastname: Tanaka
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Shimazu
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Taiki
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authors.lastname: Yamaji
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sasazuki
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.affiliation: Division of Cancer Registry, Prevention and Epidemiology, Chiba Cancer Center Research Institute, Chiba, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Mikami
authors.affiliation: Laboratory of Public Health, School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan.
authors.forename: Kiyonori
authors.initials: K
authors.lastname: Kuriki
authors.affiliation: Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Naito
authors.affiliation: Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Aichi, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Okamoto
authors.affiliation: Department of Public Health, Nagoya City University Graduate School of Medical Sciences, Aichi, Japan.
authors.forename: Fumi
authors.initials: F
authors.lastname: Kondo
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Aichi, Japan.
authors.forename: Satoyo
authors.initials: S
authors.lastname: Hosono
authors.affiliation: Department of Public Health, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Miyagawa
authors.affiliation: Department of Epidemiology for Community Health and Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Ozaki
authors.affiliation: Department of Preventive Medicine, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: Sakurako
authors.initials: S
authors.lastname: Katsuura-Kamano
authors.affiliation: Department of Geriatric Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Keizo
authors.initials: K
authors.lastname: Ohnaka
authors.affiliation: Department of Public Health, Showa University School of Medicine, Tokyo, Japan.
authors.forename: Hinako
authors.initials: H
authors.lastname: Nanri
authors.affiliation: Department of Community Medicine Management, Faculty of Medicine, Shimane University, Shimane, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Tsunematsu-Nakahata
authors.affiliation: Department of Advanced Cancer Science, Yamagata University Faculty of Medicine, Yamagata, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Kayama
authors.affiliation: Department of Preventive Medicine and Public Health, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Kurihara
authors.affiliation: Faculty of Health Promotional Science, Tokoha University, Shizuoka, Japan.
authors.forename: Shiomi
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Aichi, Japan; Department of Epidemiology, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Epidemiology and Prevention Group, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Shoichiro
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mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015930:Diet Records; D004034:Diet Surveys / Q000379:methods*; D002149:Energy Intake; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D054928:Validation Studies as Topic
keywords: Dietary assessment method; Dietary records; Standardization