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Validation Information: German EPIC FFQ2
Fitting Portion Sizes in a Self-Administered Food Frequency Questionnaire
For epidemiological studies, a simple semiquantitative FFQ was developed to assess the frequency of intake of food items demonstrated with graphically displayed portion sizes. As a validation study, a random sample of 393 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study completed 2 unannounced 24-h dietary recalls (24HDR) and the FFQ during 1 y. To calculate food and nutrient intakes, we compared the use of fitted portion sizes with the use of predefined portion sizes. Fitted portion sizes were calculated by summing food intakes over the 2 24HDR and dividing the sum by the frequency of intake reported in the FFQ for each FFQ food item, leading to similar mean intakes for FFQ and 24HDR. As predefined portion sizes, amounts that had been used in previous dietary assessments in EPIC Potsdam were used. Mean intake of 12 food groups was 102% for men or women with fitted portion sizes and 79% for men and 95% for women with predefined portion sizes of intake measured with 2 24HDR. However, deattenuated, energyadjusted correlation coefficients between FFQ and 24HDR were not better for 19 nutrients by the use of fitted portion sizes, with a mean correlation coefficient of 0.53 for men and 0.56 for women. Mean correlation coefficients for food groups also were similar for fitted and predefined portion sizes. Fitting portion sizes using recent reference data from a random sample of study participants improved the quantitative assessment of food and nutrient intake, but not ranking of study participants, compared with predefining portion sizes based on prior knowledge.
Total number of nutrients validated: 18
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: 8
- Micronutrients: 9
|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|
|24hr Recall||Adults||Both||Energy (kcal)||0.33 (P)|
|Energy (kcal)||0.25 (P)|
|Protein (g)||0.19 (P)|
|Protein (g)||0.19 (P)|
|Fat (g)||0.29 (P)|
|Fat (g)||0.25 (P)|
|Saturated Fat (g)||0.42 (P)|
|Saturated Fat (g)||0.29 (P)|
|MUFA (g)||0.24 (P)|
|MUFA (g)||0.26 (P)|
|PUFA (g)||0.15 (P)|
|PUFA (g)||0.18 (P)|
|Carbohydrates (g)||0.44 (P)|
|Carbohydrates (g)||0.31 (P)|
|Calcium (mg)||0.38 (P)|
|Calcium (mg)||0.47 (P)|
|Iron (mg)||0.27 (P)|
|Iron (mg)||0.20 (P)|
|Folic Acid (µg)||0.25 (P)|
|Folic Acid (µg)||0.26 (P)|
|Vitamin C (mg)||0.37 (P)|
|Vitamin C (mg)||0.24 (P)|
|Fruit (g)||2.7||201||0.48 (P)||-392||397|
|Fruit (g)||-2.3||187||0.41 (P)||-368||364|
|Vegetables (g)||4.2||119||0.30 (P)||-229||237|
|Vegetables (g)||-0.3||114||0.24 (P)||-225||224|
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.
Nothlings U, Hoffmann K, Bergmann MM, Boeing H. Fitting portion sizes in a self-administered food frequency questionnaire. The Journal of nutrition. 2007;137(12):2781-6. Food Frequency Questionnaire.The Journal of Nutrition, 137:2781-2786.