Dairy products, calcium and prostate cancer risk

Abstract

In a prospective study of 10 011 men with 815 prostate cancer cases, despite plausible biological mechanisms, neither increasing intake levels of dairy products nor calcium from dairy products (P trend; 0.23 and 0.64, respectively), or calcium supplements was associated with prostate cancer risk (relative risk, 1.05; 95% confidence interval, 0.84 -1.31). (Gronberg, 2003). Although its incidence is increasing steadily in almost all countries, few modifiable predictors for the disease have been identified (Gronberg, 2003). Well-established risk factors, such as age, family history, race, and country of residence, are not amenable to modification and have limited utility as primary prevention strategies.Calcium intake, a modifiable dietary factor, has recently been proposed as a risk factor for prostate cancer. Evidence from in vitro and animal studies suggests that risk may be increased by higher levels of calcium, since these suppress 1,25-dihydroxyvitamin D 3 , the most active form of vitamin D 3 , that inhibits the proliferation of prostate cancer cells and promotes their differentiation (Schwartz et al, 1995(Schwartz et al, , 1997Giovannucci, 1998). However, relevant studies have yielded inconsistent results (Gao et al, 2005), although few studies have considered intake from calcium supplementation, that can provide higher doses than dietary intake. Given calcium's importance in the prevention of diseases such as osteoporosis, we conducted a study of the question in a large cohort of men. MATERIALS AND METHODS SubjectsThe Harvard Alumni Health Study, initiated in the 1960s, is an ongoing cohort study of men who entered Harvard University, United States, as undergraduates between 1916 and 1950. Health information is obtained from subjects via questionnaires mailed at periodic intervals. The present study utilises data from a questionnaire mailed in 1988 that included detailed information on diet, and eligible subjects were 12 805 men who responded. We excluded men reporting cancer at baseline (n ¼ 1731) and those not providing information on dairy product intake (n ¼ 60). Of the remaining 11 014 men, we successfully followed 10 011 (90.9%) for the development of prostate cancer; these men represent the subjects for the present analysis. Assessment of calcium intake and other factorsThe 1988 questionnaire assessed diet using an abbreviated version (23 food items) of a validated semiquantitative food frequency questionnaire (Willett et al, 1985(Willett et al, , 1987. Men indicated their usual daily intake of seven different dairy products (whole milk, low fat milk, cream, ice cream, yogurt, cheese and butter) using pre-specified responses ranging from 'almost never' to 'six or more times per day.' On the original, longer version of the questionnaire, 13 dairy items were assessed. However, we believe our assessment of calcium intake using the seven items s reasonably valid. While we did not directly validate our 7-item questionnaire against the longer questionnaire, a previous study that assessed fewer items -mil...

Animal foods, protein, calcium and prostate cancer risk: the European Prospective Investigation into Cancer and Nutrition

“…However, few studies have reported on protein intake in relation to risk (Severson et al, 1989;Schuurman et al, 1999;Chan et al, 2000), and, to our knowledge, this is the first study to examine specifically the association of dairy protein in risk. An alternative hypothesis is that dairy products may increase prostate cancer risk via their high calcium content, and our finding of a positive association with calcium intake is consistent with some (Chan et al, 2001;Gao et al, 2005;Tseng et al, 2005;Giovannucci et al, 2006;Kesse et al, 2006;Ahn et al, 2007;Mitrou et al, 2007), but not all, prospective studies (Koh et al, 2006;Severi et al, 2006;Rohrmann et al, 2007). It has been suggested that a high calcium intake may increase risk by suppressing the synthesis of 1,25-dihydroxyvitamin D, which has an antitumour effect on human prostatic cells in vitro (Giovannucci, 1998).…”

Estimation of total prostate specific antigen values through artificial intelligence modelling

“…Thus, this important finding inferred from this study is consistent with the reported studies [15,16]. Some clinical researches demonstrated the relation of calcium intake with the risk of prostate cancer, and concluded that high calcium intake can reduce the risk of advanced prostate cancer [17,18]. In this direction, the important results of the mentioned researches support the result of the current study.…”

Dairy Products, Calcium Intake, and Risk of Prostate Cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

“…Calcium, a major nutrient in dairy products, has also been associated with increased prostate cancer risk (11,12,(17)(18)(19)(20), although other studies do not support this association (13,(21)(22)(23)(24).…”