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.
Am J Clin Nutr
; 74(2): 188-96, 2001 Aug.
Article
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| MEDLINE
| ID: mdl-11470719
ABSTRACT
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 approximately 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.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Potasio
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Sodio
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Ácido Fólico
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Nitrógeno
Tipo de estudio:
Clinical_trials
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Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Límite:
Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Am J Clin Nutr
Año:
2001
Tipo del documento:
Article
País de afiliación:
Reino Unido