title: Beta-carotene concentration in buccal mucosal cells with and without dysplastic oral leukoplakia after long-term beta-carotene supplementation in male smokers.
abstract: OBJECTIVE
  To measure the beta-carotene concentration in buccal mucosal cells in smoking men who had received long-term beta-carotene (BC) supplementation in a controlled trial. To assess the association of cellular BC on the prevalence of dysplasia in oral leukoplakia.
  
  
  METHODS
  An end-of-trial examination of a part of subjects in the Alpha-Tocopherol, Beta Carotene Cancer Prevention Study.
  
  
  METHODS
  343 men who for 5-7 years had received BC (20 mg/d) or alpha-tocopherol (AT) (50 mg/d), or both of these or placebo. BC concentration of buccal mucosal cells was compared in the subjects with BC supplementation (n = 173) to that of those without it (n = 170). Oral mucosae were examined clinically and lesions showing leukoplakia histopathologically.
  
  
  RESULTS
  Mean (s.d.) BC concentration in buccal mucosal cells was 7.7 (10.3)mg/kg protein in the subjects who received BC compared to 1.1 (1.7) mg/kg protein in those who did not. The BC concentration in the cells of supplemented subjects correlated with their serum BC levels (P < 0.001). AT supplementation had no effect on BC concentration nor was daily amount of smoking statistically significantly associated with the BC concentration in buccal cells. Altogether 17 subjects showed oral leukoplakia, 7 had dysplasia. In these 7 subjects, the BC concentration in buccal mucosal cells did not differ statistically significantly compared to subjects with only hyperkeratosis (n = 10) (F-test, P = 0.74).
  
  
  CONCLUSIONS
  After long-term BC supplementation, BC concentration in oral mucosal cells was 7-fold greater than without supplementation. There was no evidence to support an association between cellular BC concentration and precancerous lesions among the few subjects having them in their oral mucosae.
authors.affiliation: University of Helsinki, Institute of Dentistry, Finland.
authors.forename: K E
authors.initials: KE
authors.lastname: Liede
authors.forename: G
authors.initials: G
authors.lastname: Alfthan
authors.forename: J H
authors.initials: JH
authors.lastname: Hietanen
authors.forename: J K
authors.initials: JK
authors.lastname: Haukka
authors.forename: L M
authors.initials: LM
authors.lastname: Saxen
authors.forename: O P
authors.initials: OP
authors.lastname: Heinonen
mesh_terms: D000368:Aged; D006801:Humans; D007972:Leukoplakia, Oral / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000737:chemistry*; D009062:Mouth Neoplasms / Q000517:prevention & control; D012907:Smoking / Q000009:adverse effects*; D019207:beta Carotene / Q000008:administration & dosage / Q000032:analysis* / Q000627:therapeutic use*
chemical_list: D019207:beta Carotene