title: Dietary intake and supplement use of vitamins C and E and upper respiratory tract infection.
abstract: OBJECTIVE
  Antioxidants are regulators of immune function and may play a role in upper respiratory tract infections (URTI). We investigated the potential effects of dietary intake from food and supplement use of vitamins C and E on the risk of self-reported URTI.
  
  
  METHODS
  We conducted a population-based cohort study of 1509 Swedish men and women ages 20 to 60 with a follow-up period of 4 months. Participants reported a total of 1181 occurrences of URTI. Poisson regression model was used to control for age, sex, and other confounding factors.
  
  
  RESULTS
  Among women, we found that the incidence rate ratio (IRR) for high intake of vitamin C (>200 mg/d) from food was 0.69 (95% CI 0.49-0.98) compared with low intake (<100 mg/d). This association was not seen among men, for whom the IRR was 1.16 (95% CI 0.79-1.70) for high intake of vitamin C (>150 mg/d) compared with low intake (<50 mg/d). We saw no protective effect of vitamin E from food among either men or women, but a possible protective effect of vitamin C and E supplement use among men (vitamin C, 0.69 [95% CI 0.47-1.02]; vitamin E, 0.56 [95% CI 0.33-0.95]), although not among women.
  
  
  CONCLUSIONS
  The present study is the first observational study to suggest that intake of vitamin C from food is sufficient to lower the risk of URTI among women. In addition, it appears that supplement use of vitamin E and vitamin C may reduce the risk of URTI among men, who overall had a lower intake of vitamin C from food than women.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Osher Center for Integrative Medicine, Stockholm. Elinor@Fondell.com
authors.forename: Elinor
authors.initials: E
authors.lastname: Fondell
authors.forename: Olle
authors.initials: O
authors.lastname: Bälter
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Rothman
authors.forename: Katarina
authors.initials: K
authors.lastname: Bälter
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage; D001205:Ascorbic Acid / Q000008:administration & dosage*; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000517:prevention & control*; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014810:Vitamin E / Q000008:administration & dosage*; D014815:Vitamins / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000975:Antioxidants; D014815:Vitamins; D014810:Vitamin E; D001205:Ascorbic Acid