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Validation Information: FFQ (Adolescents)

Araujo 2010

Validation and Calibration of a Semiquantitative Food Frequency Questionnaire Designed for Adolescents

Background Epidemiologic studies must have a reliable method for evaluating food intake; therefore, valid, precise, and practical instruments are essential.
Objective To assess the relative validity and estimate the calibration factors of a semiquantitative food frequency questionnaire (FFQ) for adolescents.
Design Validation and calibration study.
Subjects/settings This study enrolled 169 adolescents from Rio de Janeiro, Brazil. A set of three food records was used as the reference method.
Statistical analyses performed The relative validity was analyzed according to weighted K values for the quartile categorization of energy and nutrient intakes, Pearson correlation
coefficients, and the Bland-Altman method. To estimate the calibration factors for the FFQ, linear regression models, including the food record means as dependent variables and the FFQ estimations as independent variables were developed for boys and girls.
Results The weighted K values ranged from 0.28 to 0.44 for the raw data and from 0.16 to 0.39 for the deattenuated and energy-adjusted data. The Pearson correlation coefficients ranged from 0.33 to 0.46, and the mean agreement varied from 62% to 143%. The calibration factors estimated for boys ranged from 0.15 to 0.48, and the factors estimated for girls ranged from 0.14 to 0.47. The mean energy and nutrient intakes estimated by the calibrated FFQ were similar to the means estimated by the food records; however, the standard deviations were smaller for the calibrated FFQ estimations.
Conclusions The tested FFQ is a suitable tool for ranking energy and nutrients intake in the studied group. Calibration factors are needed to estimate energy and nutrient intake means and should be used to correct raw data as well as association measurements based on FFQ data.

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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
6 months (Before the interview)
Portion Size Measures info
Typical reference portions were used for items like bananas and bread, the most frequent measurements reported in food records were used for other items
Reporting Method info
Retrospective; Usual
Format info
Supplements Measured
Not reported
Administration Method info
Interview administered

Study Information

Study Location
Rio de Janeiro, Brazil
Associated Nutrient Database
Nutwin software (based on US Department of Agriculture nutrient database) and Brazilian Food Composition Table
Comparator Validated Against
Food Diary Estimated


Sample Size
Age of Population

Range: 12-19 years; Mean (SD): 15.4 (1.94) years

Other Notable Characteristics
Subjects included a variety of socioeconomic status'

Total number of nutrients validated: 7 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: 3
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
Estimated Food Diary Adolescents Both Energy (kcal) 0.41 (P) 0.43 (W) 34 4 62 (%) 304 (%)
Protein (g) 0.34 (P) 0.38 (W) 40 4 52 (%) 277 (%)
Fat (g) 0.33 (P) 0.27 (W) 29 4 49 (%) 353 (%)
Carbohydrates (g) 0.46 (P) 0.44 (W) 37 4 67 (%) 335 (%)
Fibre (g) 0.41 (P) 0.33 (W) 35 4 66 (%) 482 (%)
Calcium (mg) 0.40 (P) 0.40 (W) 40 4 47 (%) 571 (%)
Iron (mg) 0.34 (P) 0.28 (W) 32 4 56 (%) 343 (%)

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.

Araujo MC, Yokoo EM, Pereira RA. Validation and calibration of a semiquantitative food frequency questionnaire designed for adolescents. Journal of the American Dietetic Association. 2010 Aug 31;110(8):1170-7.