Inverse Associations between Plasma Lycopene and Other Carotenoids and Prostate Cancer

Inverse Associations between Plasma Lycopene and Other Carotenoids and Prostate Cancer1

Center for Human Nutrition, University of California at Los Angeles School of Medicine [Q-Y. L., D. H., V. L. W. G.], and Department of Epidemiology, University of California at Los Angeles School of Public Health and Jonsson Comprehensive Cancer Center [J-C. H., Z-F. Z.], Los Angeles, California 90095; Departments of Pathology [V. E. R., C. C-C.] and Medicine [H. I. S.], Memorial Sloan-Kettering Cancer Center, New York, New York 10021; and Arizona Cancer Center, Tucson, Arizona 85724 [J. R. M.]

Abstract

Although dietary intake of tomatoes and tomato products containing lycopene has been reported to reduce the risk of prostate cancer, few studies have been done on the relationship between plasma lycopene and other carotenoids and prostate cancer. This case-control study was conducted to investigate the effects of plasma lycopene, other carotenoids, and retinol, as well as α- and γ-tocopherols on the risk of prostate cancer. The study included 65 patients with prostate cancer and 132 cancer-free controls; all of them were interviewed using a standard epidemiological questionnaire at the Memorial Sloan-Kettering Cancer Center from 1993 to 1997. Plasma levels of carotenoids, retinol, and tocopherols were measured by high performance liquid chromatography. An unconditional logistic regression model was used in bivariate and multivariate analyses using Statistical Analysis System (SAS). After adjusting for age, race, years of education, daily caloric intake, pack-years of smoking, alcohol consumption, and family history of prostate cancer, significantly inverse associations with prostate cancer were observed with plasma concentrations of the following carotenoids: lycopene [odds ratio (OR), 0.17; 95% confidence interval (CI), 0.04–0.78; P for trend, 0.0052] and zeaxanthin (OR, 0.22; 95% CI, 0.06–0.83; P for trend, 0.0028) when comparing highest with lowest quartiles. Borderline associations were found for lutein (OR, 0.30; 95% CI, 0.09–1.03; P for trend, 0.0064) and β-cryptoxanthin (OR, 0.31; 95% CI, 0.08–1.24; P for trend, 0.0666). No obvious associations were found for α- and β-carotenes, retinol, and α- and γ-tocopherols. Our study confirmed the inverse associations between lycopene, other carotenoids such as zeaxanthin, lutein, and β-cryptoxanthin, and prostate cancer. This study provides justification for further research on the associations between lycopene and other antioxidants and the risk of prostate cancer.

Footnotes

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵1 Supported in part by NIH, National Institute of Environmental Health Sciences, National Cancer Institute, Department of Health and Human Services, Grants ES06718, CA77954, CA09142, CA16042, and CA 42710, by awards from CapCURE, an award from Carolan funds, a seed Grant from the UCLA Jonsson Comprehensive Cancer Center Foundation, and the Weisman Fund.
↵2 To whom requests for reprints should be addressed, at Center for Human Nutrition, UCLA School of Medicine, 900 Veteran Avenue, 12-217 Warren Hall, Box 951742, Los Angeles, CA 90095-1742. Phone: (310) 825-3126; Fax: (310) 206-5264; E-mail: qlu{at}mednet.ucla.edu
↵3 The abbreviations used are: MSKCC, Memorial Sloan-Kettering Cancer Center; NCI, National Cancer Institute; UCLA, University of California at Los Angeles; OR, odds ratio; CI, confidence interval; HHHQ, Health Habits and History Questionnaire.
- Accepted April 11, 1901.
- Received October 12, 1900.
- Revision received March 8, 1901.