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Validation Information: Oxford FFQ
Using biochemical markers to assess the validity of prospective dietary assessment methods and the effect of energy adjustment
The validity of dietary assessment methods in a group of women aged 50-65 y was evaluated with use of biochemical markers. Estimates of nitrogen, potassium, and carotene intakes from weighed-food and estimated records yielded higher correlations with urinary nitrogen, urinary potassium, and serum concentrations of carotenoids than did estimates from food-frequency questionnaires and 24-h recalls. When the residuals method of energy adjustment was used, the correlations between intakes of nitrogen and potassium estimated from food-frequency questionnaires and 24-h recalls and intakes derived from weighed-food records improved, and the high correlations between biochemical markers and estimates from weighed-food records were maintained. In addition, with use of this method, estimates for nitrogen and potassium intakes from food-frequency questionnaires showed the most improvement in comparison with the biochemical markers; however, the correlations of crude nitrogen and potassium with crude energy intake were highest. Carotene intake was not related to energy intake, so that correlations between the intake of carotene assessed by any method and the plasma β-carotene concentration did not improve with energy adjustment and between-person variability was not reduced. Energy adjustment with either the energy density or residuals method did not alter the ranking of accuracy of various dietary assessment methods in comparison with weighed-food records or biochemical markers in either the total group of subjects or those who were identified as having provided valid weighed-food records.
Total number of nutrients validated: 3
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: 2
|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||Female Only||Urinary Nitrogen||0.24 (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.
Bingham SA, Day NE. Using biochemical markers to assess the validity of prospective dietary assessment methods and the effect of energy adjustment. The American journal of clinical nutrition. 1997 Apr 1;65(4):1130S-7S.