Vegetable and fruit consumption and prostate cancer risk: A cohort study in The Netherlands

Maastricht University, Maestricht, Limburg, Netherlands
Cancer Epidemiology Biomarkers & Prevention (Impact Factor: 4.13). 09/1998; 7(8):673-80.
Source: PubMed


The association between 21 vegetables and eight fruits and prostate cancer risk was assessed in the Netherlands Cohort Study among 58,279 men of ages 55-69 years at baseline in 1986. After 6.3 years of follow-up, 610 cases with complete vegetable data and 642 cases with complete fruit data were available for analysis. In multivariate case-cohort analyses, the following rate ratios (RRs) and 95% confidence intervals (CIs) for vegetable consumption were found (comparing highest versus lowest quintile): total vegetables (RR, 0.80; CI, 0.57-1.12); prepared vegetables (RR, 0.85; CI, 0.61-1.19); and raw vegetables (RR, 0.96; CI, 0.69-1.34). For vegetables categorized in botanical groups, no associations were found except for consumption of pulses (RR, 0.71; CI, 0.51-0.98; P for trend, 0.01). The RRs for total fruit and citrus fruit were 1.31 (CI, 0.96-1.79) and 1.27 (CI, 0.93-1.73), respectively; the corresponding Ps for trend were 0.02 and 0.01, respectively. In a continuous model, no association for total fruit was observed. Individual vegetables and fruits were evaluated as continuous variables (g/day). Nonsignificant inverse associations (RRs per increment of 25 g/day) were found for consumption of kale (RR, 0.74), raw endive (RR, 0.72), mandarins (RR, 0.75), and raisins or other dried fruit (RR, 0.49). Observed positive associations were significant for consumption of leek (RR, 1.38) and oranges (RR, 1.07) and nonsignificant for sweet peppers (RR, 1.60) and mushrooms (RR, 1.49). Results in subgroups of cases were more or less consistent with the overall results. From our study, we cannot conclude that vegetable consumption is important in prostate cancer etiology, but for certain vegetables or fruits, an association cannot be excluded.

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    • "In epidemiological studies, such as case-control and cohort studies, the possible relationship between allium vegetables intake and prostate cancer risk has been investigated (Key et al., 1997; Schuurman et al., 1998; Hsing et al., 2002; Hodge et al., 2004; Galeone et al., 2006; Kirsh et al., 2007; Brasky et al., 2011; Hardin et al., 2011; Salem et al., 2011), but the findings are not all clearly consistent, possibly as a result of a lack of statistical power in the individual studies. In addition, to "
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    ABSTRACT: Objective: To evaluate the relationship between allium vegetable intake and risk of prostate cancer. Methods: A systematic literature search up to May 2013 was carried out in PubMed, EMBASE, Scopus, Web of Science, Cochrane register, and Chinese National Knowledge Infrastructure (CNKI) databases, and the references of retrieved articles were also screened. The summary relative risks with 95% confidence interval for the highest versus the lowest intake of allium vegetables were calculated. Heterogeneity and publication bias were also evaluated. Results: A total of nine epidemiological studies consisting of six case-control and three prospective cohort studies were included. We found a significantly decreased risk of prostate cancer for intake of allium vegetables (OR = 0.82, 95% CI 0.70, 0.97). Moreover, in the subgroup analysis stratified by allium vegetable types, significant associations were observed for garlic (OR = 0.77, 95% CI 0.64-0.91) but not onions (OR = 0.84, 95% CI 0.62-1.13). Conclusions: Allium vegetables, especially garlic intake, are related to decreased risk of prostate cancer. Because of the limited number of studies, further well-designed prospective studies are warranted to confirm the findings of our study.
    Preview · Article · Jul 2013 · Asian Pacific journal of cancer prevention: APJCP
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    • "Dietary cohort studies that did not report associations with prostate cancer incidence frequently had lower lycopene and tomato intake compared with studies that report an association. A dietary cohort study based in The Netherlands between 1986 to 1992 did not report an association between tomato intake and prostate cancer incidence [22]. While this cohort took place between the same time period as the initial HPFS analysis, tomato consumption was low compared with the HPFS. "
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    ABSTRACT: Lycopene has been proposed to protect against prostate cancer through various properties including decreased lipid oxidation, inhibition of cancer cell proliferation, and most notably potent antioxidant properties. Epidemiologic studies on the association between lycopene and prostate cancer incidence have yielded mixed results. Detection of an association has been complicated by unique epidemiologic considerations including the measurement of lycopene and its major source in the diet, tomato products, and assessment of prostate cancer incidence and progression. Understanding this association has been further challenging in the prostate-specific antigen (PSA) screening era. PSA screening has increased the detection of prostate cancer, including a variety of relatively indolent cancers. This paper examines the lycopene and prostate cancer association in light of epidemiologic methodologic issues with particular emphasis on the effect of PSA screening on this association.
    Full-text · Article · May 2012 · Journal of Oncology
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    • "They emerged at a time when interest in the carotenoids was fading, primarily because of the failure of supplemental b-carotene to reduce lung cancer or total cancer incidence in three randomized, placebo-controlled clinical trials (The Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group, 1994; Hennekens et al., 1996; Omenn et al., 1996). However, in another cohort study, including 58,279 men aged 55–69 years at baseline and living in the Netherlands, neither tomatoes (RR = 1.05 for a 25 g/day increase, equivalent to a serving/week) nor tomato juice (RR = 1.12 for a 25 g/day increase) were associated with decreased prostate cancer risk (Schuurman et al., 1998). The design for this study was comparable to that of the Giovannucci et al. (1995) study. "
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    ABSTRACT: The epidemiologic data tend to support an association between intake of tomato-based foods and a lower risk of prostate cancer. The observed inverse association may be due to lycopene though this is unproven at this point. Even two servings a week of a rich source of bioavailable lycopene, such as tomato sauce, was related to a substantially lower risk of prostate cancer. Whereas chance alone is highly unlikely to account for the consistent inverse association with tomato-based products, confounding by other variables, particularly dietary, cannot be definitively excluded as alternative explanations. Of greatest concern is that a lycopene-rich diet is acting as an indicator of a diet rich in vegetables and fruits that may lower risk of prostate cancer through other phytochemicals. An important historical lesson is provided by β-carotene, for which an abundance of evidence based on questionnaires and blood levels suggested a benefit on various cancers (93), particularly lung cancer, but recent intervention trials of β-carotene supplementation have not confirmed this benefit (60). In retrospect it appears difficult, if not impossible to differentiate β-carotene intake from that of a general dietary pattern that is high in fruits and vegetables. In contrast, this is not the case for lycopene. Other carotenoids in prostate tissue tend to be significantly interrelated, but lycopene content does not appear to be correlated appreciably with other carotenoids (83). In the Health Professionals Follow-Up Study and the Seventh-Day Adventist study, tomato-based products and lycopene were associated with a lower prostate cancer risk, but fruits and vegetables, individually and in aggregate, and other carotenoids were not associated with prostate cancer risk. These results are consistent with findings from other studies that overall vegetable and fruit consumption appear unrelated to prostate cancer incidence (36, 94, 95). It is more difficult to separate specific effects of lycopene from that of other potentially beneficial compounds in tomatoes; however, based on similarity of results for plasma predictors of lycopene with predictors of prostate cancer risk, the putative compound would be expected to have similar bioavailability characteristics as lycopene. Thus, with regard to practical recommendations, the available data are most conservatively interpreted as supporting a potential benefit of increased consumption of tomatoes and tomato-based products. To attribute a specific effect to lycopene or a particular isomer of this carotenoid would require much more research. Additional studies by epidemiologists, clinical investigators, cancer biologists, and nutritional scientists are underway, and answers to many questions concerning tomatoes, lycopene, and prostate cancer should be forthcoming.
    Full-text · Article · Jul 1998 · Proceedings of The Society for Experimental Biology and Medicine
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