Dietary antioxidants and the risk of lung cancer.

The relation between the intake of retinoids, carotenoids, vitamin E, vitamin C, and selenium and the subsequent risk of lung cancer was studied among 4,538 initially cancer-free Finnish men aged 20-69 years. During a follow-up of 20 years beginning in 1966-1972, 117 lung cancer cases were diagnosed. Inverse gradients were observed between the intake of carotenoids, vitamin E, and vitamin C and the incidence of lung cancer among nonsmokers, for whom the age-adjusted relative risks of lung cancer in the lowest tertile of intake compared with that in the highest tertile were 2.5 (p value for trend = 0.04), 3.1 (p = 0.12), and 3.1 (p less than 0.01) for the three intakes, respectively. Adjustment for various potential confounding factors did not materially alter the results, and the associations did not seem to be due to preclinical cancer. In the total cohort, there was an inverse association between intake of margarine and fruits and risk of lung cancer. The relative risk of lung cancer for the lowest compared with the highest tertile of margarine intake was 4.0 (p less than 0.001), and that for fruits was 1.8 (p = 0.01). These associations persisted after adjustment for the micronutrient intakes and were stronger among nonsmokers. The results suggest that carotenoids, vitamin E, and vitamin C may be protective against lung cancer among nonsmokers. Food sources rich in these micronutrients may also have other constituents with independent protective effects against lung cancer.