Seasonal variation in intake of carotenoids and vegetables and fruits among white men in New Jersey.

In a population-based case-control study of lung cancer among New Jersey men, usual adult consumption of many vegetables and fruits was included in the interview to assess the protective potential of carotenoids. With data from 900 controls the percentage of New Jersey white men who eat specific vegetables and fruits primarily in certain seasons, the relative importance of in-season and out-of-season consumption, and the median length of season were determined. Although first asking whether a food item was consumed all-year-round or primarily in certain seasons and then asking for the appropriate frequency of consumption facilitated the interview, obtaining out-of-season frequency of consumption and length of season was not necessary. Substituting 0 for reported out-of-season frequencies and 3 mo for reported season lengths reduced slightly the observed associations between diet and lung cancer risk but did not modify the overall pattern noted. Carotenoid intake in winter-fall was estimated to be about two-thirds that in summer-spring.