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Validation Information: 7 day Estimated Food Diary
Use of biological markers to validate self-reported dietary intake in a random sample of the European Prospective Investigation into Cancer United Kingdom Norfolk cohort
Background: The validity of dietary assessment methods should be established before diet-disease associations are reported.
Objective: Our objective was to validate a 7-d food diary and a food-frequency questionnaire (FFQ) against independent biomarkers of intake in urine (nitrogen, potassium, and sodium) and blood (plasma ascorbic acid).
Design: A total of 146 healthy middle-aged men and women were recruited from the European Prospective Investigation into Cancer UK Norfolk cohort, a free-living cohort of ∼25000 persons. Over a 9-mo period, urinary nitrogen, potassium, and sodium were estimated from 2-6 complete 24-h urine collections in 134 subjects and plasma ascorbic acid was estimated from 2-3 fasting blood samples in 118 subjects. Subjects completed 2 FFQs and two 7-d food diaries.
Results: In men and women combined, correlations between 24-h urinary nitrogen excretion and dietary intake from the 7-d food diary were high (r = 0.57-0.67) compared with those for the FFQ (r = 0.21-0.29). Similarly, correlations between urinary potassium and dietary potassium were higher for the 7-d food diary (r = 0.51-0.55) than for the FFQ (r = 0.32-0.34). There was no overall difference in correlations between plasma ascorbic acid and dietary vitamin C between the 7-d food diary (r = 0.40-0.52) and the FFQ (r = 0.44-0.45).
Conclusions: These data indicate that, despite increased subject burden, the 7-d food diary provided a better estimate of nitrogen and potassium intakes than did the FFQ in this study population. However, with respect to plasma ascorbic acid, both the FFQ and
7-d food diary provided a similar ranking of subjects according to vitamin C intake.
Total number of nutrients validated: 4
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: 1
- 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|
|Biomarkers||Adults, Elderly||Male Only||Sodium (mg)||0.39 (S)|
|Plasma Ascorbic Acid (µmol/L)||0.41 (P)|
|Urinary Nitrogen||0.51 (S)|
|Biomarkers||Adults, Elderly||Female Only||Sodium (mg)||0.17 (S)|
|Plasma Ascorbic Acid (µmol/L)||0.56 (P)|
|Urinary Nitrogen||0.48 (S)|
|Biomarkers||Adults, Elderly||Both||Sodium (mg)||0.48 (S)|
|Plasma Ascorbic Acid (µmol/L)||0.53 (P)|
|Urinary Nitrogen||0.66 (S)|
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.
McKeown NM, Day NE, Welch AA, Runswick SA, Luben RN, Mulligan AA, et al. Use of biological markers to validate self-reported dietary intake in a random sample of the European Prospective Investigation into Cancer United Kingdom Norfolk cohort. The American journal of clinical nutrition. 2001 Aug 1;74(2):188-96.