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Validation Information: FFQ (II) (Nutrients)

Ocke 1997

The Dutch EPIC Food Frequency Questionnaire. II. Relative Validity and Reproducibility for Nutrients

Background. A self-administered semi-quantitative food frequency questionnaire (FFQ) was developed for the Dutch cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).

Methods. The reproducibility and relative validity of nutrient intake as assessed by this questionnaire were investigated in a population of 121 men and women. To assess the relative validity, 12 monthly 24-hour recalls served as reference method, together with four determinations of 24-hour urinary nitrogen excretion, predicted basal metabolic rate, and serum b-carotene and a-tocopherol levels.

Results. Protein and, among women, energy intake were underestimated by the questionnaire compared to urinary nitrogen excretion and the basal metabolic rate, respectively. The underestimation for protein decreased with increasing protein intake. Pearson correlation coefficients between nutrient intakes assessed by repeated questionnaires ranged from 0.70 to 0.94 among men and from 0.59 to 0.94 among women. Correlation coefficients between nutrient intakes assessed by the questionnaire and 24-hour recalls ranged from 0.26 to 0.83 for men and from 0.35 to 0.90 for women, with medians of 0.59 and 0.58, respectively. Correlation coefficients between 0.2 and 0.5 were observed for b-carotene and vitamin C for men and for b-carotene and vitamin E for women. Associations with serum b-carotene (r = –0.16 for men; 0.13 for women) and a-tocopherol (0.23 and 0.15, respectively) were much poorer than those obtained with 24-hour recalls. Correlations between protein intake and 24-hour urinary nitrogen excretion were 0.47 and 0.53, respectively.

Conclusions. The FFQ seems adequate for ranking subjects according to intake of energy, macronutrients, dietary fibre and retinol, but it does not yield such good results for b-carotene, vitamin C for men, vitamin E for women.

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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
1 year
Portion Size Measures info
Portion sizes were either specified in household units or shown in colour photographs taken by a professional food photographer
Reporting Method info
Format info
Supplements Measured
Administration Method info

Study Information

Study Location
Associated Nutrient Database
Adapted computerised version of the 1993 Dutch Food Composition Table
Comparator Validated Against
24hr Recall


Sample Size
63 (Male), 58 (Female)
Age of Population

Mean (SD): 42.6 (11.1) years

(data taken from paper 1)
Male Only, Female Only
Other Notable Characteristics
Subjects were recruited from towns in the Netherlands from ongoing projects

Total number of nutrients validated: 8 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: 4
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 Male Only Energy (kcal) 72 0.71 (P)
Protein (g) 2 0.61 (P)
Fat (g) 12 0.69 (P)
Carbohydrate (g) 3 0.72 (P)
Fibre (g) 1.5 0.51 (P)
Retinol (mg) 0.08 0.57 (P)
Vitamin C (mg) 21 0.39(P)
24hr Recall Adults Female Only Energy (kcal) 96 0.58 (P)
Protein (g) 2 0.51 (P)
Fat (g) 10 0.58 (P)
Carbohydrate (g) 4 0.66 (P)
Fibre (g) 1.3 0.67 (P)
Retinol (mg) 0.1 0.57 (P)
Vitamin C (mg) 22 0.58 (P)

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.

Ocke M C, Bueno-De-Mesquita H Bas, Pols M.A, Smit H.A, Van Stavern W.A. & Kromhout D. The Dutch EPIC Food Frequency Questionnaire. II. Relative Validity and Reproducibility for Nutrients. (1997). International Journal of Epidemiology. (1997) 26 (1) supplement 1