Stability of blood (pro) vitamins during four years of storage at - 20°C : consequences for epidemiologic research.
We studied the effects of frozen storage on (pro) vitamin concentrations in EDTA-plasma and whole blood.
Aliquots from 55 samples were analyzed before storage and after 3,6,12,24,36 and 48 months at - 20oC.
Dramatic decreases occurred for EDTA-plasma concentrations of vitamin E between 6 and 12 months, vitamin A, total carotenoids and bêta-carotene after 1 year, and whole blood niacin.
A smaller decrease was observed for folic acid at 1 year of storage, but the level remained constant thereafter.
The vitamins D, B6, B12 (EDTA-plasma), B1 and B2 (whole blood) showed no decline during 4 years of storage.
With the exception of folic acid, the observed decreases varied considerably among subjects.
Therefore using EDTA-plasma stored longer than 1 year at - 20oC will result in highly attenuated odds ratios when assessing the relationship between vitamin A, carotenoids, or vitamin E with a given disease.
Attenuation will also occur when using niacin concentrations in whole blood stored for 4 years at - 20oC.
Mots-clés Pascal : Vitamine, Stabilité chimique, Sang, Conservation, Prélèvement, Homme, Méthode étude, Epidémiologie
Mots-clés Pascal anglais : Vitamin, Chemical stability, Blood, Conservation, Samplings, Human, Investigation method, Epidemiology
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 95-0381468
Code Inist : 002B30A01A1. Création : 01/03/1996.