title: Distribution of serum concentrations of alpha-tocopherol and gamma-tocopherol in the US population.
abstract: BACKGROUND
  Although the population distribution of serum concentrations of alpha-tocopherol has been described in the United States, little is known about the distribution of gamma-tocopherol or the ratio of alpha-tocopherol to gamma-tocopherol.
  
  
  OBJECTIVE
  Our aim was to describe the distribution of serum concentrations of alpha-tocopherol and gamma-tocopherol in a nationally representative sample of US adults.
  
  
  METHODS
  We reviewed data from 4087 adults aged >/=20 y who participated in the National Health and Nutrition Examination Survey (1999-2000). Concentrations of alpha-tocopherol and gamma-tocopherol were measured by using HPLC with ultraviolet-visible wavelength detection.
  
  
  RESULTS
  The arithmetic mean (+/-SEM) of serum concentrations of alpha-tocopherol was 30.09 +/- 0.45 micromol/L, the median was 25.94 micromol/L, and the geometric mean (+/-SEM) was 27.39 +/- 0.38 micromol/L. The arithmetic mean of serum concentrations of gamma-tocopherol was 5.74 +/- 0.22 micromol/L, the median was 5.25 micromol/L, and the geometric mean was 4.79 +/- 0.18 micromol/L. The median ratio of alpha-tocopherol to total cholesterol was 4.93 micromol/mmol, that of gamma-tocopherol to total cholesterol was 1.03 micromol/mmol, and that of alpha-tocopherol to gamma-tocopherol was 4.53 micromol/mmol. Concentrations of alpha-tocopherol increased significantly (P for trend < 0.001) with age and were significantly (P = 0.015) lower in men than in women. African Americans and Mexican Americans had significantly (P < 0.001) lower concentrations of alpha-tocopherol than did whites. The median concentrations of gamma-tocopherol showed a trend with respect to age, did not differ significantly between men and women, and were slightly but nonsignificantly lower in white participants than in African American or Mexican American participants.
  
  
  CONCLUSIONS
  Sociodemographic variations in serum concentrations of alpha-tocopherol and gamma-tocopherol exist among US adults.
authors.affiliation: Division of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA. e.ford@cdc.gov
authors.forename: Earl S
authors.initials: ES
authors.lastname: Ford
authors.forename: Rosemary L
authors.initials: RL
authors.lastname: Schleicher
authors.forename: Ali H
authors.initials: AH
authors.lastname: Mokdad
authors.forename: Umed A
authors.initials: UA
authors.lastname: Ajani
authors.forename: Simin
authors.initials: S
authors.lastname: Liu
mesh_terms: D000328:Adult; D001741:Black or African American; D017677:Age Distribution; D000368:Aged; D002784:Cholesterol / Q000097:blood; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged; D009749:Nutrition Surveys; D009752:Nutritional Status; D017678:Sex Distribution; D014481:United States; D044465:White People; D024502:alpha-Tocopherol / Q000097:blood*; D024504:gamma-Tocopherol / Q000097:blood*
chemical_list: D024504:gamma-Tocopherol; D002784:Cholesterol; D024502:alpha-Tocopherol