Prospective Studies of Dairy Product and Calcium Intakes and Prostate Cancer Risk: A Meta-Analysis

Boston University, Boston, Massachusetts, United States
Journal of the National Cancer Institute (Impact Factor: 12.58). 12/2005; 97(23):1768-77. DOI: 10.1093/jnci/dji402
Source: PubMed


The Dietary Guidelines for Americans 2005 recommends that Americans increase their intake of dairy products. However, some studies have reported that increasing dairy product intake is associated with an increased risk of prostate cancer. We conducted a meta-analysis to examine associations between intakes of calcium and dairy products and the risk of prostate cancer.
We searched Medline for prospective studies published in English-language journals from 1966 through May 2005. We identified 12 publications that used total, advanced, or fatal prostate cancer as end points and reported associations as relative risks (RRs) with 95% confidence intervals (CIs) by category of dairy product or calcium intake. Data were extracted using standardized data forms. Random-effects models were used to pool study results and to assess dose-response relationships between dairy product or calcium intakes and the risk of prostate cancer. We conducted sensitivity analyses by changing criteria for inclusion of studies or by using fixed-effects models. All statistical tests were two-sided.
Men with the highest intake of dairy products (RR =1.11 [95% CI = 1.00 to 1.22], P = .047) and calcium (RR = 1.39 [95% CI = 1.09 to 1.77], P = .018) were more likely to develop prostate cancer than men with the lowest intake. Dose-response analyses suggested that dairy product and calcium intakes were each positively associated with the risk of prostate cancer (Ptrend = .029 and .014, respectively). Sensitivity analyses generally supported these associations, although the statistical significance was attenuated. The pooled relative risks of advanced prostate cancer were 1.33 (95% CI = 1.00 to 1.78; P = .055) for the highest versus lowest intake categories of dairy products and 1.46 (95% CI = 0.65 to 3.25; P > .2) for the highest versus lowest intake categories of calcium.
High intake of dairy products and calcium may be associated with an increased risk of prostate cancer, although the increase appears to be small.

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    • "Among individual food groups/nutrients a high consumption of dairy are related to an increased risk in several studies, including the European Prospective Investigation into Cancer and Nutrition (2014) and studies in Canada (Raimondi et al., 2010) and Japan (Kurahashi et al., 2008). However, the results of two meta-analyses of the relation between dairy product intake and PC provided conflicting conclusions: one showed a significantly positive association (Gao et al., 2005) and the other (supported by the National Dairy Council) showed an overall null association (Huncharek et al., 2008). High consumption of meat has been also associated with PC risk (John et al., 2011; Punnen et al., 2011). "
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    ABSTRACT: The aim of the present study was to determine the association between the socio-demographic, lifestyle factors, and dietary habits with the risk of prostate cancer (PC) in a case-control study of Spanish men. None of the socio-demographic, lifestyle or dietetic variables was found predictors of PC risk. Body mass index was associated with an increased risk for aggressive PC and fruit consumption with lower Gleason scores, thus less aggressive cancers. Nonetheless, after applying Bonferroni correction, these variables were not still associated with PC aggressiveness. More adequately, powered epidemiological studies that measure the effect of lifestyle and dietary intake in PC risk and aggressiveness are warranted to further elucidate the role of these modifiable factors on PC etiology.
    International Journal of Food Sciences and Nutrition 09/2015; DOI:10.3109/09637486.2015.1077786 · 1.21 Impact Factor
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    • "Most epidemiologic studies [1,2,3,4,5,6], but not all [7,8], have reported an increase in prostate cancer risk with an increased milk intake. To elucidate the effect of milk on prostate cancer, numerous experimental studies have tried to identify hazardous ingredients in milk, such as calcium [6,9], estrogen [10], and insulin-like growth factor-1 (IGF-1) [11]. However, among the components of milk, protein has been enigmatic. "
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    ABSTRACT: Purpose Despite most epidemiologic studies reporting that an increase in milk intake affects the growth of prostate cancer, the results of experimental studies are not consistent. In this study, we investigated the proliferation of prostate cancer cells treated with casein, the main protein in milk. Materials and Methods Prostate cancer cells (LNCaP and PC3), lung cancer cells (A459), stomach cancer cells (SNU484), breast cancer cells (MCF7), immortalized human embryonic kidney cells (HEK293), and immortalized normal prostate cells (RWPE1) were treated with either 0.1 or 1 mg/mL of α-casein and total casein extracted from bovine milk. Treatments were carried out in serum-free media for 72 hours. The proliferation of each cell line was evaluated by an 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results α-Casein and total casein did not affect the proliferations of RWPE1, HEK293, A459, SNU484, MCF7, HEK293, or RWPE1 cells. However, PC3 cells treated with 1 mg/mL of α-casein and casein showed increased proliferation (228% and 166%, respectively), and the proliferation of LNCaP cells was also enhanced by 134% and 142%, respectively. The proliferation mechanism of α-casein in PC3 and LNCaP cells did not appear to be related to the induction of Insulin-like growth factor-1 (IGF-1), since the level of IGF-1 did not change upon the supplementation of casein. Conclusions The milk protein, casein, promotes the proliferation of prostate cancer cells such as PC3 and LNCaP.
    08/2014; 32(2):76-82. DOI:10.5534/wjmh.2014.32.2.76
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    • "However, in our study, eggs consumption was associated with a lower incidence of advanced prostate cancer, and no association was observed with fatal prostate cancer, while these results need to be interpreted with caution because of the few studies available. Another plausible mechanism through which eggs could increase the risk of prostate cancer include the effect of calcium in prostatic epithelium, which was the only mineral presented a significant increased risk of prostate cancer (Gao et al., 2005; Huncharek et al., 2008). "
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    ABSTRACT: Objective: Egg consumption has been suggested to increase the risk of colorectal and some other cancers. The present study summarized and quantified the current evidence relating dietary intake of eggs and prostate cancer. Materials and methods: Literature searches were conducted to identify peer-reviewed manuscripts published up to July 2012. Twenty manuscripts from nine cohort studies and 11 case-control studies were identified. Summary risk estimates with 95% confidence intervals (CIs) were calculated for case-control and cohort studies separately. Results: Neither the case-control not the cohort studies showed any association of prostate cancer incidence with egg consumption (case-control studies: odds ratio 1.09, 95% CI 0.86-1.31; cohort studies: relative risk 0.97, 95% CI 0.97-1.07). The results were consistent in subgroup analysis. Furthermore, no association was observed between egg consumption and prostate cancer-specific mortality. Conclusions: Our analyses provided no evidence of a significant influence of egg consumption on prostate cancer incidence and mortality. However, more studies, particularly large prospective studies, are needed.
    Asian Pacific journal of cancer prevention: APJCP 09/2012; 13(9):4677-81. DOI:10.7314/APJCP.2012.13.9.4677 · 2.51 Impact Factor
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