To examine the effect of specific dietary carotenoids and their primary plant food sources on lung cancer risk in a population-based case-control study of women.
Data were available for 587 incident primary lung cancer cases and 624 controls frequency matched to cases based on age. A modified version of the 100-item NCI-Block food-frequency questionnaire was used to obtain information concerning usual diet 2-3 years prior to interview.
In models adjusted for age, total calorie intake, pack-years of smoking, and education, beta-carotene, beta-cryptoxanthin, lutein + zeaxanthin, and total carotenoid intake were each associated with a significantly lower risk of lung cancer. Several vegetable groups were predictive of lower lung cancer risk, particularly the frequency of total vegetable intake. Individual and total carotenoids were no longer significantly associated with lower lung cancer risk in models adjusted for total vegetable intake. However, total vegetable intake remained significantly inversely associated with risk in models adjusted for total carotenoids.
These results indicate that consumption of a wide variety of vegetables has a greater bearing on lung cancer risk in a population of smoking and nonsmoking women than intake of any specific carotenoid or total carotenoids.