title: Validity and reliability of an FFQ for use with adolescents in Ho Chi Minh City, Vietnam.
abstract: OBJECTIVE
  The present study evaluates the reliability and validity of an FFQ designed for use with adolescents in urban Vietnam.
  
  
  METHODS
  A cohort study was conducted between December 2003 and June 2004. The FFQ was administered three times over a 6-month period (FFQ 1-3) and nutrient intakes were compared to those obtained from four 24 h recalls collected over the same period (24 h recalls 1-4) using crude, energy-adjusted and de-attenuated correlation coefficients. The level of agreement between the two measurements was also evaluated with Bland-Altman analysis. The percentage of nutrient intakes classified within one quintile, as well as quadratic-weighted kappa statistics, were calculated.
  
  
  METHODS
  Ho Chi Minh City, Vietnam.
  
  
  METHODS
  A total of 180 students were recruited in three junior high schools.
  
  
  RESULTS
  Coefficients ranged from 0.22 for retinol to 0.78 for fibre for short-term reliability, and from 0.30 for retinol to 0.81 for zinc for long-term reliability. Coefficients for nutrient intakes between the mean of the three FFQ and mean of four 24 h recalls were mostly around 0.40, but higher for energy-adjusted nutrients. After allowing for within-person variation, the mean coefficient was 0.52 for macronutrients and 0.46 for micronutrients. There were a relatively high proportion of nutrient intakes classified within one quintile and a small number grossly misclassified. Kappa values shows 'fair' to 'good' agreement for all food/nutrient categories, while the Bland-Altman plots indicated that the FFQ is accurate in assessing nutrient intake at a group level.
  
  
  CONCLUSIONS
  This newly developed FFQ is a valid tool for measuring nutrient intake in adolescents in urban Vietnam.
authors.affiliation: Department of Community Health, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, 86/2 Thanh Thai Street, Ward 12, District 10, Vietnam. hongutc@yahoo.com
authors.forename: Tang K
authors.initials: TK
authors.lastname: Hong
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dibley
authors.forename: David
authors.initials: D
authors.lastname: Sibbritt
mesh_terms: D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena / Q000502:physiology*; D015331:Cohort Studies; D004032:Diet; D004034:Diet Surveys; D002149:Energy Intake / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D015596:Nutrition Assessment; D009765:Obesity / Q000517:prevention & control; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D014504:Urban Health; D014505:Urban Population; D014744:Vietnam