THE PROTECTIVE EFFECT OF BETA-CAROTENE AND RETINOL ON VENTILATORY FUNCTION IN AN ASBESTOS-EXPOSED COHORT

The association between serum beta-carotene or retinol concentration a nd level of ventilatory function was investigated in a population of a sbestos-exposed men with a high rate of current and former cigarette s moking. The study population consisted of 816 subjects enrolled in the pilot component of the Carotene and Retinol Efficacy Trial (CARET), a placebo-controlled trial of supplemental beta-carotene and retinyl pa lmitate for the chemoprevention of lung cancer. Data available for ana lysis included baseline questionnaire, spirometry, chest X-ray, food f requency questionnaire, and serum beta-carotene and retinol concentrat ions. Serum beta-carotene concentration was associated with FEV(1) (p < 0.05) and FVC (p < 0.05), with an approximately 100-ml increase over predicted values associated with raising the serum concentration from the 25th to the 75th percentile of the distribution in the study popu lation (absolute difference = 155 ng/ml), even after adjustment for th e confounding effects of asbestos exposure and cigarette smoking. Rais ing the serum retinol concentration from the 25th to the 75th percenti le (absolute difference = 211 ng/ml) was associated with an approximat ely 70 mi increase in FVC (p < 0.05) over the predicted value. These r esults provide support for the hypothesis that beta-carotene and retin ol have a protective effect on loss of ventilatory function.