INTAKE OF VITAMIN-E, VITAMIN-C, AND VITAMIN-A AND RISK OF LUNG-CANCER- THE NHANES-I EPIDEMIOLOGIC FOLLOW-UP-STUDY

The relation between the dietary intake of vitamins E, C, and A (estim ated by a 24-hour recall) and lung cancer incidence was examined in th e First National Health and Nutrition Examination Survey Epidemiologic Followup Study cohort of 3,968 men and 6,100 women, aged 25-74 years, During a median follow-up period of 19 years (from 1971-1975 to 1992) , 248 persons developed lung cancer, Adjusted for potential confounder s using Cox proportional hazards regression methods with age as the un derlying time variable, the relative risk of lung cancer for subjects in the highest quartile of vitamin C intake compared with those in the lowest quartile was 0.66 (95% confidence interval (CI) 0.45-0.96), Fo r vitamin A intake, a protective effect was observed only for its frui t and vegetable component (carotenoids) among current smokers (relativ e risk = 0.49, 95% CI 0.29-0.84), but this was modified by the intensi ty of smoking (a statistically significant effect (relative risk = 0.3 3, 95% CI 0.13-0.84) was observed only for those in the lowest tertile of pack-years of smoking), The vitamin E intake-lung cancer relation was modified by the intensity of smoking with a significant protective effect confined to current smokers in the lowest tertile of pack-year s of smoking (relative risk = 0.36, 95% CI 0.16-0.83), Overall, there was no additional protective effect of supplements of vitamins E, C, a nd A beyond that provided through dietary intake, When vitamin E, vita min C, and carotenoid intakes were examined in combination, a strong p rotective effect was observed for those in the highest compared with t hose in the lowest quartile of all three intakes (relative risk = 0.32 , 95% CI 0.14-0.74), These data provide support for a protective role of dietary vitamins E and C and of carotenoids against lung cancer ris k but with a modification in effects by the intensity of cigarette exp osure, While smoking avoidance is the most important behavior to reduc e lung cancer risk, the daily consumption of a variety of fruits and v egetables that provides a combination of these nutrients and other pot ential protective factors may offer the best dietary protection agains t lung cancer.