The diuretic effects of alcohol and caffeine and total water intake misclassification.
Data from the 1994 USDA nationwide survey (CSFII) on 190 non-smoking males (aged 20 29) were used to propose a method for adjusting total water intake for the diuretic effects of caffeine and alcohol, and evaluate the potential for related misclassification bias.
The data were processed on a per meal basis.
Under the assumption that subjects were in water balance at the start of the survey day, water losses due to caffeine (1.17 ml/mg caffeine) and alcohol (10 ml/g alcohol) were subtracted from crude intake estimates.
If water intake for one meal was inadequate for excretion of the associated osmotic load at 750 mosmol/l, water losses for the subsequent meal were reduced by 32%. Unadjusted and adjusted mean total water intakes differed by 321.5 g. Misclassification appeared worst at higher water intakes.
Linear regression models, each with a water intake variable as an independent variable and body mass index as the outcome, were fit to evaluate the potential for alcohol-and caffeine-related misclassification bias.
Misclassification resulted in large changes (all>10%) in linear regression estimates of effect.
Future studies of water-disease relationships, especially those intending to compare extremes of total water intake, should consider caffeine-and alcohol-related misclassification bias.
Mots-clés Pascal : Etats Unis, Amérique du Nord, Amérique, Homme, Evaluation, Consommation alimentaire, Boisson alcoolisée, Caféine, Diurèse, Bilan eau, Besoin hydrique, Méthodologie, Erreur estimation
Mots-clés Pascal anglais : United States, North America, America, Human, Evaluation, Food intake, Alcoholic beverage, Caffeine, Diuresis, Water balance, Water requirement, Methodology, Estimation error
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0190744
Code Inist : 002B30A01A1. Création : 16/11/1999.