Beta-Carotene, vitamin A, and lung cancer chemoprevention: results of an intermediate endpoint study.
A randomized, placebo-controlled clinical trial of beta-carotene and retinol was conducted with 755 former asbestos workers as study subjects. The targeted endpoint for the intervention study was a reduction in the incidence and prevalence of sputum atypia. The dosage of 50 mg beta-carotene/d and 25,000 IU retinol/d on alternate days resulted significant increases in serum concentrations of both agents with no clinically significant toxicity. Skin yellowing was observed in approximately 35% of patients and may have contributed adversely to protocol adherence. Baseline analysis revealed that smoking and drinking were associated with lower concentrations of serum beta-carotene, even after dietary carotene intake was adjusted for (P < 0.0001). Baseline concentrations of retinol were apparently lowered by smoking (P < 0.002) and increased by drinking (P < 0.0001). Drinking and smoking also were significantly related to lower beta-carotene concentrations after supplementation (P < 0.001). No significant reduction in sputum atypia was observed after treatment.
D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000627:therapeutic use*; D002338:Carotenoids / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D014801:Vitamin A / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D019207:beta Carotene
D000975:Antioxidants; D019207:beta Carotene; D014801:Vitamin A; D002338:Carotenoids