Prospective study of fruit and vegetable intake and risk of prostate cancer.
BACKGROUND
Several epidemiologic studies have reported associations between fruit and vegetable intake and reduced risk of prostate cancer, but the findings are inconsistent and data on clinically relevant advanced prostate cancer are limited.


METHODS
We evaluated the association between prostate cancer risk and intake of fruits and vegetables in 1338 patients with prostate cancer among 29,361 men (average follow-up = 4.2 years) in the screening arm of the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Participants completed both a general risk factor and a 137-item food-frequency questionnaire at baseline. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs). All statistical tests were two-sided.


RESULTS
Vegetable and fruit consumption was not related to prostate cancer risk overall; however, risk of extraprostatic prostate cancer (stage III or IV tumors) decreased with increasing vegetable intake (RR = 0.41, 95% CI = 0.22 to 0.74, for high versus low intake; P(trend) = .01). This association was mainly explained by intake of cruciferous vegetables (RR = 0.60, 95% CI = 0.36 to 0.98, for high versus low intake; P(trend) = .02), in particular, broccoli (RR = 0.55, 95% CI = 0.34 to 0.89, for >1 serving per week versus <1 serving per month; P(trend) = .02) and cauliflower (RR = 0.48, 95% CI = 0.25 to 0.89 for >1 serving per week versus <1 serving per month; P(trend) = .03). We found some evidence that risk of aggressive prostate cancer decreased with increasing spinach consumption, but the findings were not consistently statistically significant when restricted to extraprostatic disease.


CONCLUSIONS
High intake of cruciferous vegetables, including broccoli and cauliflower, may be associated with reduced risk of aggressive prostate cancer, particularly extraprostatic disease.
Kirsh
Victoria A
VA
Research Unit, Division of Preventive Oncology, Cancer Care Ontario, Toronto, ON, Canada.
Peters
Ulrike
U
Mayne
Susan T
ST
Subar
Amy F
AF
Chatterjee
Nilanjan
N
Johnson
Christine C
CC
Hayes
Richard B
RB
D000230:Adenocarcinoma / Q000453:epidemiology* / Q000473:pathology; D000368:Aged; D019607:Brassicaceae; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D005006:Ethnicity / Q000706:statistics & numerical data; D005247:Feeding Behavior; D005500:Follow-Up Studies; D005638:Fruit; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009361:Neoplasm Invasiveness; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000473:pathology; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D012907:Smoking / Q000453:epidemiology; D018724:Spinacia oleracea; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D014675:Vegetables