title: Reproducibility and relative validity of a semi-quantitative food frequency questionnaire for Chinese pregnant women.
abstract: BACKGROUND
  Food frequency questionnaire (FFQ) is a reliable tool to estimate dietary intake in large nutritional epidemiological studies, but there is lack of a current and validated FFQ for use in urban Chinese pregnant women. This study aimed to evaluate the reproducibility and validity of a semi-quantitative FFQ designed to estimate dietary intake among urban pregnant women in a cohort study conducted in central China.
  
  
  METHODS
  In the reproducibility study, a sample of 123 healthy pregnant women completed the first FFQ at 12-13 weeks gestation and the second FFQ 3-4 weeks later. To validate the FFQ, the pregnant women completed three 24-h recalls (24HRs) between the intervals of two FFQs.
  
  
  RESULTS
  The intraclass correlation coefficients of two administrations of FFQ for foods ranged from 0.23 (nuts) to 0.49 (fruits) and for nutrients from 0.24 (iodine) to 0.58 (selenium) and coefficients were all statistically significant. The unadjusted Pearson correlation coefficients between two methods ranged from 0.28 (beans) to 0.53 (fruits) for foods and from 0.15 (iodine) to 0.59 (protein) for nutrients. Energy-adjusted and de-attenuated correlation coefficients for foods ranged from 0.35 (beans) to 0.56 (fruits) and for nutrients from 0.11 (iodine) to 0.63 (protein), and all correlations being statistically significant except for iodine, sodium and riboflavin. On average, 67.0% (51.2%-80.5%) of women were classified by both methods into the same or adjacent quintiles based on their food intakes, while 68.5% (56.1%-77.2%) of women were classified as such based on nutrient intakes. Extreme misclassifications were very low for both foods (average of 2.0%) and nutrients (average of 2.2%). Bland-Altman Plots also showed reasonably acceptable agreement between two methods.
  
  
  CONCLUSIONS
  This FFQ is a reasonably reliable and valid tool for assessing most food and nutrient intakes of urban pregnant women in central China.
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Qiu
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Chunrong
authors.initials: C
authors.lastname: Zhong
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Kewei
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Hubei Maternal and Child Health Hospital, Wuhan, 430070, Hubei, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Xiao
authors.affiliation: Hubei Maternal and Child Health Hospital, Wuhan, 430070, Hubei, China.
authors.forename: Nianhua
authors.initials: N
authors.lastname: Yi
authors.affiliation: The Central Hospital of Wuhan, Wuhan, 430014, Hubei, China.
authors.forename: Guoping
authors.initials: G
authors.lastname: Xiong
authors.affiliation: Jiangan Maternal and Child Health Hospital, Wuhan, 430014, Hubei, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Jiangan Maternal and Child Health Hospital, Wuhan, 430014, Hubei, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Hao
authors.affiliation: Department of Epidemiology and Biostatistics, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wei
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.
authors.forename: Nianhong
authors.initials: N
authors.lastname: Yang
authors.affiliation: Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China. xxyxf@mails.tjmu.edu.cn.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D044466:Asian People; D015992:Body Mass Index; D015331:Cohort Studies; D004034:Diet Surveys; D002149:Energy Intake; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D011939:Mental Recall; D015596:Nutrition Assessment; D011247:Pregnancy; D015203:Reproducibility of Results; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D055815:Young Adult