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Validation Information: FFQ (North China)

Wang 2008

Validity and reproducibility of a food frequency questionnaire designed for residents in North China

The objective of this study was to evaluate the validity of a Xi’an food frequency questionnaire (FFQ) designed for application in an international case-control colorectal cancer study. The FFQ was administered to 125 participants twice over 1-year interval. Four 24-hour dietary recalls (24-HDRs) were conducted with the same participants in each season of the year. Comparative validation was assessed by comparing the nutrient intakes derived from the 24-HDRs and the FFQ-2, and reproducibility was estimated by comparing the nutrient intakes from two FFQs. In the validation study, the mean deattenuated correlation coefficients for nutrients between the 24-HDRs and the FFQ-2 ranged from 0.35 to 0.84 in the males. The female results were slightly lower than the male’s. The mean percentage of classification into the same quartile was 38% for the males and 35% for the females.

In the reproducibility study, the mean crude correlation coefficients between the two FFQs were from 0.41 to 0.68 in the males and from 0.36 to 0.66 in the females. The newly developed Xi’an FFQ appears to be reasonably valid and reliable for most nutrients but would benefit from the addition of nutritional supplements and seasonings for assessing dietary intake in older persons in Xi’an, China

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Validation Information

Year of Publication

Tool Information

Dietary Exposure Measured
Full Nutrient
Tool Type
Food Frequency Questionnaire
Timeframe Tool Measures info
Portion Size Measures info
Domestic food portion sizes (Chinese food weight unit of 50g) specified for food items
Reporting Method info
Format info
Supplements Measured
Administration Method info

Study Information

Study Location
Xi'an City, Shaanxi province, China
Associated Nutrient Database
China Food Composition 2004
Comparator Validated Against
24hr Recall


Sample Size
120 (Gender split unknown)
Adults, Elderly
Age of Population

Range (SD): 50-80 (7.9) years

Male Only, Female Only
Other Notable Characteristics
Random selection of individuals from Xi'an city Shaanxi province Municipal Resident Registry Office (age range 50-79 yrs). Participants required to be free of diseases influencing food consumption.

Total number of nutrients validated: 11 info

Not all of the nutrients validated in the validation studies are included in the table below, as statistical data was only selected to be displayed for a number of nutrients, this included:

  • Energy
  • Fat
  • Saturated Fat
  • Mono-unsaturated Fat
  • Poly-unsaturated Fat
  • Carbohydrates
  • Protein
  • Sugar
  • Non‐starch polysaccharides(NSP)
  • Sodium
  • Calcium
  • Iron
  • Zinc
  • Retinol
  • Folate
  • Folic Acid
  • Vitamin B12
  • Vitamin C
  • Fruit & Vegetables
  • Urinary Nitrogen

To find information on the other validated nutrients please read the validation study.

  • Energy
  • Macronutrients: 4
  • Micronutrients: 7
Comparator Lifestage Sex Nutrient Measured info Mean Difference Standard Deviation info Correlation Coefficient info Cohen's Kappa Coefficient Percentage Agreement Percentage Agreement Categories info Lower Limits of Agreement Upper Limits of Agreement
24hr Recall Adults, Elderly Male Only Energy (kcal) -36 (Median) 0.71 (P) 45 4
Protein (g) -9 (Median) 0.52 (P) 30 4
Fat (g) 14 (Median) 0.50 (P) 34 4
Carbohydrate (g) -8 (Median) 0.56 (P) 38 4
Fibre (g) -5 (Median) 0.26 (P) 38 4
Vitamin C (mg) 3 (Median) 0.49 (P) 43 4
24hr Recall Adults, Elderly Female Only Protein (g) 0 (Median) 0.29 (P) 37 4
Carbohydrate (g) 15 (Median) 0.45 (P) 37 4
Fibre (g) 4 (Median) 0.31 (P) 27 4
Vitamin C (mg) 39 (Median) 0.45 (P) 38 4
Fat (g) 8 (Median) 0.36 (P) 33 4
Energy (kcal) 263 (Median) 0.35 (P) 38 4

Some results have been calculated using statistical techniques based on the published data.

For further information on statistical terms click on Statistical tests used in validation studies

All correlations coefficients in the table are unadjusted unless stated otherwise. For adjusted correlation coefficients and other statistical methods used in the study e.g. paired t-tests, please read the validation articles.

  • # Adjusted
  • † Energy adjusted.
  • ‡ For loge-transformed, energy-adjusted nutrient intakes.
  • ^ Adjacent included.
  • ᵟ Participants provided identical responses.
  • (w) = Weighted.

Wang X, Rina S & Yan H. Validity and reproducibility of a food frequency questionnaire designed for residents in north china. Asia Pacific Journal of Clinical Nutrition. 2008. 17 (4) 629-634