title: Effects of long-term intake of retinol on selected clinical and laboratory indexes.
abstract: BACKGROUND
  Chemopreventive agents developed to be used in a moderate-risk but otherwise healthy population need to be both efficacious and to have minimal adverse effects.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the adverse effects of long-term retinol intake in a skin cancer chemoprevention trial in a large population at moderate risk for skin cancer.
  
  
  METHODS
  Participants (n = 2297) were randomly assigned to receive retinol [7576 retinol equivalents (RE), or 25000 IU] or a placebo daily. The adverse effects of retinol intake were studied by monitoring 14 clinical symptoms and laboratory indexes. The median follow-up time was 3.8 y.
  
  
  RESULTS
  No adverse effects concerning the 14 symptoms were observed. Significant differences in alkaline phosphatase (P < 0.0001), triacylglycerol (P < 0.0001), cholesterol (P = 0.04), and HDL (P = 0.01) were observed over time between the 2 groups. After 49 mo of follow-up, alkaline phosphatase was 7% higher, triacylglycerol was 11% higher, cholesterol was 3% higher, and HDL was 1% lower in the retinol group than in the placebo group.
  
  
  CONCLUSIONS
  Because a 1% increase in cholesterol concentrations has been reported to be associated with a 2% increase in coronary artery disease risk, long-term ingestion of 7576 RE vitamin A/d should be considered with caution. However, further studies are needed to confirm this finding.
authors.affiliation: University of Arizona Cancer Center and the Arizona Health Sciences Center, Tucson, USA. brenda.cartmel@yale.edu
authors.forename: B
authors.initials: B
authors.lastname: Cartmel
authors.forename: T E
authors.initials: TE
authors.lastname: Moon
authors.forename: N
authors.initials: N
authors.lastname: Levine
mesh_terms: D000368:Aged; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004311:Double-Blind Method; D005260:Female; D006403:Hematologic Tests; D006801:Humans; D008297:Male; D010787:Photosensitivity Disorders / Q000097:blood / Q000188:drug therapy*; D012878:Skin Neoplasms / Q000517:prevention & control; D014801:Vitamin A / Q000008:administration & dosage*
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014801:Vitamin A