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Validation Information: FFQ (Adolescents)
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.
Total number of nutrients validated: 7
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:
- Saturated Fat
- Mono-unsaturated Fat
- Poly-unsaturated Fat
- Non‐starch polysaccharides(NSP)
- Folic Acid
- Vitamin B12
- Vitamin C
- Fruit & Vegetables
- Urinary Nitrogen
To find information on the other validated nutrients please read the validation study.
- Macronutrients: 4
- Micronutrients: 3
|Comparator||Lifestage||Sex||Nutrient Measured||Mean Difference||Standard Deviation||Correlation Coefficient||Cohen's Kappa Coefficient||Percentage Agreement||Percentage Agreement Categories||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.