Prostate cancer incidence and intake of fruits, vegetables and related micronutrients: the multiethnic cohort study* (United States).
OBJECTIVE
To describe the relationship between the intake of fruits, vegetables, and related vitamins and antioxidants, and the risk of prostate cancer in male participants in a large multiethnic cohort study.


METHODS
Food and nutrient intakes in 1993-1996 were calculated from a detailed food frequency questionnaire (FFQ) designed to account for the food and nutrient intake of the ethnic groups represented in the study (82,486 African-American, Japanese-American, Native-Hawaiian, Latino and White males included here). Follow-up for incident cancers utilized local SEER registries. Vital status was ascertained using state death files. Data on PSA utilization from a later questionnaire was also examined.


RESULTS
A total of 3,922 incident cancer cases were ascertained during follow-up. Modestly increased risks of prostate cancer were observed in relation to higher intakes of several food items including light green lettuce and dark leafy green vegetables. Notably, no significant protective associations of any foods were seen, including tomato intake; and intakes of two complex foods containing tomato sauce (pizza and Spanish rice) were associated with modest increases in risk. PSA test use was significantly and positively related to intake of some of these same items, implying a degree of disease detection-bias. Analysis of non-localized and high grade disease (1,345 cases) showed no significant protective associations with overall fruits and vegetables intake, related micronutrients, or with intake of selected complex food items.


CONCLUSIONS
We found no statistically significant evidence of a protective effect against prostate cancer of higher levels of intake of any of these foods, associated micronutrients or supplements. A possible explanation for the positive associations with risk of several of the foods normally considered to be healthy is detection bias, since "healthy" dietary intake was related to greater use of the PSA test.
Stram
Daniel O
DO
Department of Preventive Medicine, USC/Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA. stram@usc.edu
Hankin
Jean H
JH
Wilkens
Lynne R
LR
Park
Sohee
S
Henderson
Brian E
BE
Nomura
Abraham M Y
AM
Pike
Malcolm C
MC
Kolonel
Laurence N
LN
D001741:Black or African American; D000368:Aged; D044467:American Indian or Alaska Native; D000704:Analysis of Variance; D001213:Asian; D014408:Biomarkers, Tumor / Q000097:blood; D002140:California / Q000208:ethnology; D015331:Cohort Studies; D004435:Eating; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D005638:Fruit; D006254:Hawaii / Q000208:ethnology; D006630:Hispanic or Latino; D006801:Humans; D015994:Incidence; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage / Q000032:analysis; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000276:immunology; D012044:Regression Analysis; D012307:Risk Factors; D018426:SEER Program; D011795:Surveys and Questionnaires; D014675:Vegetables; D044465:White People
D014408:Biomarkers, Tumor; D018977:Micronutrients; D017430:Prostate-Specific Antigen