St. Mayne et al., DIETARY BETA-CAROTENE AND LUNG-CANCER RISK IN UNITED-STATES NONSMOKERS, Journal of the National Cancer Institute, 86(1), 1994, pp. 33-38
Background: Approximately 15% of all lung cancer deaths in the United
States (about 22350 deaths annually) may not be directly attributable
to active cigarette smoking. Consumption of beta carotene, which is de
rived almost exclusively from intake of fruits and vegetables, has bee
n associated with a reduced risk of lung cancer in smokers. However, s
tudies examining this association in nonsmokers, particularly nonsmoki
ng men, are limited. Purpose: The purpose of this study was to examine
whether dietary factors including beta carotene and retinol are assoc
iated with a reduced risk for lung cancer in nonsmoking men and women.
Methods: A population-based, matched case-control study of lung cance
r in nonsmokers was conducted in New York State from 1982 to 1985. Die
tary interviews were completed for 413 individually matched case-contr
ol pairs of subjects. To determine whether the relationship between di
etary intake from specific food groups and lung cancer differed by typ
e of interview, smoking history, sex, age, or histologic type, we exam
ined data on the case-control pairs from each subgroup separately. The
intake of beta carotene and retinol was calculated as the weighted su
m of the monthly frequencies of consumption of food items containing t
hese nutrients, where the weights correspond to the nutrient content o
f a typical portion of the food items. Results: Consumption of greens
(P for trend <.01), fresh fruits (P for trend <.01), and cheese (P for
trend <.05) was associated with a significant dose-dependent reductio
n in risk for lung cancer, whereas consumption of whole milk (P for tr
end <.01) was associated with a significant dose-dependent increase in
risk. Use of vitamin E supplements was also protective (odds ratio =
0.55; 95% confidence interval [CI] = 0.35-0.85). Increased consumption
of the following food groups was associated with a reduction in risk
among females: vegetables (P for trend <.025), raw fruits and vegetabl
es (P for trend <.005), and dairy products (P for trend <.025). In mal
es, increased consumption of raw fruits and vegetables was associated
with a reduced risk for lung cancer (P for trend <.005). Dietary beta
carotene (OR = 0.70; 95% CI = 0.50-0.99), but not retinol (OR = 0.98;
95% CI = 0.82-1.17), was significantly associated with risk reduction.
Conclusions: This is the largest study to date of dietary factors and
lung cancer in nonsmokers; results suggest that dietary beta carotene
, raw fruits and vegetables, and vitamin E supplements reduce the risk
of lung cancer in nonsmoking men and women.