title: Development and validation of a calcium intake questionnaire for postmenopausal women in China.
abstract: OBJECTIVE
  Develop and evaluate a food frequency questionnaire (FFQ) for assessing calcium intake in Chinese postmenopausal women.
  
  
  METHODS
  An interviewer-conducted FFQ that asks respondents about their consumption of 110 calcium-containing foods over the previous week was developed and administered to 21 randomly selected postmenopausal women from Chengdu. This FFQ uses both the traditional weight-estimation method of assessing portion size in China and a new volume-estimation method. Test-retest reliability was assessed by re-administering the questionnaire two weeks later and validity was assessed by comparing the computed daily calcium intake to that obtained by a researcher-conducted 4-day food record.
  
  
  RESULTS
  Estimates of calcium intake derived from the volume-estimation method were significantly lower than estimates derived from the traditional weight-estimation method (median calcium intakes = 270 mg/day versus 570 mg/day), but were quite similar to those obtained from the 4-day food record (median calcium intake = 275 mg/day). The test-retest reliability and validity of the volume-estimation method (intraclass correlation coefficient (ICC) = 0.73 and 0.86, respectively) were better than those of the weight-estimation method (ICC = 0.58 and 0.39, respectively).
  
  
  CONCLUSIONS
  The reliability and validity of the traditional weight-estimation FFQ method of assessing dietary intake of nutrients in China is poor; this method may significantly overestimate dietary intakes. The proposed volume-estimation FFQ method for assessing calcium intake is a simple, interviewer-conducted method that is both reliable and valid. The calcium intake of postmenopausal women in urban China is much lower than the recommended daily allowance of 800 mg.
authors.affiliation: Department of Obstetrics and Gynecology, The Second Teaching Hospital, West China University of Medical Science, Chengdu.
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.forename: J E
authors.initials: JE
authors.lastname: Porteous
authors.forename: M R
authors.initials: MR
authors.lastname: Phillips
authors.forename: S
authors.initials: S
authors.lastname: Zheng
mesh_terms: D000368:Aged; D002136:Calcium, Dietary / Q000008:administration & dosage*; D002681:China / Q000453:epidemiology; D004435:Eating; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014505:Urban Population / Q000706:statistics & numerical data
chemical_list: D002136:Calcium, Dietary