title: Antioxidant supplement use in Women's Health Initiative participants.
abstract: BACKGROUND
  Although antioxidant supplements are widely available and commonly used in the United States, there is a lack of detailed information on their use, including types of supplements used, doses, duration of use, and changes in use over time.
  
  
  METHODS
  Antioxidant supplement use was assessed in participants in the Clinical Trial (n = 68,133) and Observational Study (n = 93,676) of the Women's Health Initiative. In-person interviews and a computerized inventory procedure were used to collect data on supplement use during baseline clinic visits from 1993 through 1998.
  
  
  RESULTS
  Antioxidant supplements were widely consumed. For example, 55.5% of participants reported taking supplemental vitamin C in some form. Supplement use was positively associated with age, education, and physical activity. Most antioxidants were consumed through multivitamins. However, high doses were commonly consumed from single supplements, with 43.9% using single vitamin C supplements taking >500 mg and 86.1% using single vitamin E supplements taking >200 IU daily. Except for beta-carotene, there were increases in the use of all supplements from 1993 to 1998.
  
  
  CONCLUSIONS
  This report demonstrates the feasibility of collecting comprehensive dietary supplement use data in large studies. These data may aid in the design of supplement use questionnaires, which could help to prevent misclassification error in epidemiologic studies of diet and disease.
authors.affiliation: Division of Preventive Medicine, University of Alabama at Birmingham, 35294, USA. jshikany@dopm.uab.edu
authors.forename: James M
authors.initials: JM
authors.lastname: Shikany
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Patterson
authors.forename: Tanya
authors.initials: T
authors.lastname: Agurs-Collins
authors.forename: Garnet
authors.initials: G
authors.lastname: Anderson
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage*; D001294:Attitude to Health; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D004522:Educational Status; D015444:Exercise; D005260:Female; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D011336:Probability; D012959:Socioeconomic Factors; D014481:United States; D016387:Women's Health
chemical_list: D000975:Antioxidants