Prospective study of calcium intake and incident and fatal prostate cancer
ABSTRACT Prostate cancer is the most common incident cancer and the second leading cause of cancer mortality in U.S. males. Higher milk intake has been relatively consistently associated with an increased risk of prostate cancer, especially advanced prostate cancer. Some data suggest that high intake of calcium might account for this association, but this relationship remains controversial. We hypothesized that high calcium intake, possibly by lowering 1,25(OH)2 vitamin D levels, is associated with poorer differentiation in prostate cancer and thereby with fatal prostate cancer. We examined calcium intake in relation to prostate cancer risk using data from the Health Professionals Follow-up Study, a prospective cohort study of 47,750 male health professionals with no history of cancer other than nonmelanoma skin cancer at baseline. We assessed total, dietary, and supplementary calcium intake in 1986, 1990, 1994, and 1998, using a validated food frequency questionnaire. We calculated the multivariable relative risk (RR) and 95% confidence intervals (95% CI) using Cox proportional hazards regression. Over 16 years of follow-up, we identified 3,544 total cases of prostate cancer, 523 advanced (extraprostatic) cases, and 312 fatal cases. Higher calcium intake was not appreciably associated with total or nonadvanced prostate cancer but was associated with a higher risk of advanced and fatal prostate cancer [for fatal prostate cancer, compared with men whose long-term calcium intake was 500-749 mg/d (excluding supplement use of <5 years); those with intakes of 1,500-1,999 mg/d had a RR, 1.87; 95% CI, 1.17-3.01; and those with > or = 2,000 mg/d had a RR, 2.43; 95% CI, 1.32-4.48; P(trend) = 0.003]. Dietary calcium and supplementary calcium were independently associated with an increased risk. For high-grade prostate cancer (Gleason > or = 7), an association was observed for high versus low calcium intake (RR, 1.89; 95% CI, 1.32-2.71; P(trend) = 0.005), but a nonsignificant, inverse association was observed for organ-confined, low-grade prostate cancer (RR, 0.79; 95% CI, 0.50-1.25; P(trend) = 0.09). In a sample of this cohort, higher calcium intake was associated with lower circulating 1,25(OH)2 vitamin D levels. Our findings suggest that calcium intakes exceeding 1,500 mg/d may be associated with a decrease in differentiation in prostate cancer and ultimately with a higher risk of advanced and fatal prostate cancer but not with well-differentiated, organ-confined cancers.
- SourceAvailable from: Bertrand Tombal
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- "Ptrend = 0.09). Very high calcium intakes (>1500 mg/day) were associated with a higher risk of advanced and fatal PCa but not with well-differentiated, organ-confined cancers.72 Similarly, Allen et al have examined the consumption of calcium in relation to the risk of PCa among 142.251 men in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study. "
ABSTRACT: As the adult population is increasing, prostate cancer (PCa) will become a considerable health problem in the next millennium. This has raised public interest in potential chemoprevention of this disease. As PCa is extremely common and generally slow to progress it is regarded as an ideal candidate for chemoprevention. At present, the 5 alpha-reductase inhibitors finasteride and dutasteride have been identified as preventive agents. This review describes whether selenium, alpha-tocopherol, isoflavones, lycopene green tea polyphenols, calcium, and resveratrol may be useful for decreasing the risk of PCa in men. Although encouraging results are present, some studies show negative results. Differences in study design, sample size, dose administered, and/or concentrations achieved in the body may be the reason for these inconsistencies. Today, chemopreventive agents may be appropriate for high-risk patients like those with high-grade prostatic intraepithelial neoplasia and other high-risk groups such as patients with elevated prostate specific antigen (PSA) and negative biopsy, rapid PSA velocity, and with a family history of PCa. Although larger randomized controlled studies are needed and epidemiologic evidence should be placed in a clinical context, physicians must be aware of these preventive opportunities in PCa care. Combinations of chemopreventive agents should be carefully investigated because mechanisms of action may be additive or synergistic.Cancer Management and Research 04/2011; 3:91-100. DOI:10.2147/CMR.S18503
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- "In this paper, we consider data from the HPFS concerning the relationship between total calcium intake and risk of fatal prostate cancer (Giovannucci et al., 2006). Total vitamin E intake was the only important confounder with respect to this relationship. "
ABSTRACT: Occupational, environmental, and nutritional epidemiologists are often interested in estimating the prospective effect of time-varying exposure variables such as cumulative exposure or cumulative updated average exposure, in relation to chronic disease endpoints such as cancer incidence and mortality. From exposure validation studies, it is apparent that many of the variables of interest are measured with moderate to substantial error. Although the ordinary regression calibration (ORC) approach is approximately valid and efficient for measurement error correction of relative risk estimates from the Cox model with time-independent point exposures when the disease is rare, it is not adaptable for use with time-varying exposures. By recalibrating the measurement error model within each risk set, a risk set regression calibration (RRC) method is proposed for this setting. An algorithm for a bias-corrected point estimate of the relative risk using an RRC approach is presented, followed by the derivation of an estimate of its variance, resulting in a sandwich estimator. Emphasis is on methods applicable to the main study/external validation study design, which arises in important applications. Simulation studies under several assumptions about the error model were carried out, which demonstrated the validity and efficiency of the method in finite samples. The method was applied to a study of diet and cancer from Harvard's Health Professionals Follow-up Study (HPFS).Biometrics 03/2011; 67(1):50-8. DOI:10.1111/j.1541-0420.2010.01423.x · 1.52 Impact Factor
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- "As for the relationship with vitamin D, both calcium and phosphorus are considered to be the “main dietary regulators” of vitamin D levels in humans . At increased concentrations, calcium has been reported to reduce levels of vitamin D . Alternatively, dietary phosphorus has the ability to influence vitamin D levels either way based on serum calcium and phosphorus concentrations . "
ABSTRACT: We aimed to investigate the effect of dietary intake of micronutrients that are metabolized and excreted via the urinary tract on bladder cancer risk. A semi-quantitative 322 item food frequency questionnaire (FFQ) was used to collect dietary data from 200 bladder cancer cases and 386 control subjects participating in the Belgian case-control study on bladder cancer risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression adjusting for age, sex, smoking characteristics, occupational exposures, and energy intake. We observed a positive association between calcium intake and bladder cancer (OR: 1.77; 95% CI: 1.00-3.15; p-trend = 0.049) and increased odds, although not statistically significant, for highest tertile of phosphorus intake (OR: 1.82; 95% CI: 0.95-3.49; p-trend = 0.06). We identified possible modification of the effects of both calcium and phosphorus by level of magnesium intake. Increased odds of bladder cancer were also observed for participants with highest intake of phosphorus and lowest intake of vitamin D (OR: 4.25; 95% CI: 1.44-12.55) and among older participants with the highest intakes of calcium (OR: 1.90; 95% CI: 1.08-3.36) and phosphorus (OR: 2.02; 95% CI: 1.05-3.92). The positive associations we observed between bladder cancer and intake of calcium and phosphorus require confirmation by other studies. The balances between inter-related micronutrients also warrant further examination.Cancer Causes and Control 03/2011; 22(3):469-78. DOI:10.1007/s10552-010-9718-z · 2.96 Impact Factor