title: Reference values for plasma concentrations of vitamin E and A and carotenoids in a Swiss population from infancy to adulthood, adjusted for seasonal influences.
abstract: In a cross-sectional survey, plasma concentrations of alpha- and gamma-tocopherol, alpha- and beta-carotene (cis and trans isomers), lycopene, and retinol were determined by reversed-phase HPLC, and ratios of plasma alpha-tocopherol to cholesterol were calculated in 208 Swiss individuals ages 0.4-38.7 years. The influence of age, sex, and season of sampling was studied. Age was a significant predictor of all plasma concentrations except alpha-carotene. No sex-related differences were observed. Season of sampling affected alpha-tocopherol and retinol (higher in winter) and gamma-tocopherol and cholesterol concentrations (higher in winter and spring than in the other seasons). After correction for seasonal influences, age differences were 0.24 micromol/L per year for alpha-tocopherol, 0.04 micromol/L per year for retinol, and 0.04 micromol/L per year for cholesterol concentrations; ratios of plasma alpha-tocopherol to cholesterol were not affected by age. We constructed age-specific reference intervals from the regression line and a multiple of the standard deviation. Separate regression equations are presented for seasons with low and high values.
authors.affiliation: Division of Gastroenterology and Nutrition, Department of Pediatrics, University of Zurich, Switzerland.
authors.forename: B M
authors.initials: BM
authors.lastname: Winklhofer-Roob
authors.forename: M A
authors.initials: MA
authors.lastname: van't Hof
authors.forename: D H
authors.initials: DH
authors.lastname: Shmerling
mesh_terms: D000293:Adolescent; D000328:Adult; D002338:Carotenoids / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D002784:Cholesterol / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007223:Infant; D000077276:Lycopene; D008297:Male; D012016:Reference Values; D012621:Seasons; D013557:Switzerland; D014801:Vitamin A / Q000097:blood*; D014810:Vitamin E / Q000097:blood*; D019207:beta Carotene / Q000097:blood
chemical_list: D019207:beta Carotene; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids; C041635:alpha-carotene; D002784:Cholesterol; D000077276:Lycopene