Serum retinol, the acute phase response, and the apparent misclassification of vitamin A status in the third National Health and Nutrition Examination Survey

Serum retinol decreases transiently during the acute phase response and can thus result in misclassification of vitamin A status. Our objective was to determine the prevalence of acute phase response activation in a representative sample of the US population, identify the factors associated with this activation, and determine whether persons with an active acute phase response have lower serum retinol concentrations. Data from the third National Health and Nutrition Examination Survey (NHANES III) were analyzed. A serum C-reactive protein (CRP) concentration >/=10 mg/L indicated an active acute phase response. Mean serum retinol was lowest in subjects aged /=10 mg/L was lowest in subjects aged