High calcium raises prostate cancer risk

Increased consumption of calcium and dairy products raises the risk of prostate cancer. Researchers at the National Cancer Institute, Rockville, Maryland used the data from the Alpha-Tocopherol, Beta-Carotene (ATBC) Cancer Prevention Study to examine dietary levels of calcium and dairy products and their relationship with prostate cancer risk. The ATBC study included 29,133 male smokers between the ages of 50 and 69 years at study enrolment who completed a 276-item food questionnaire to assess the content of their diet. During the 17-year follow-up, 1,267 cases of prostate cancer were identified. A total of 27,028 participants had completed the data available and were included in the final analysis. The results showed a strong, graded, positive association between calcium intake and total prostate cancer risk. After adjusting the data for potential variables, the risk of prostate cancer was 63 per cent greater for subjects who consumed 2,000 mg or more of calcium as compared to those who consumed less than 1,000 mg per day. A positive association was also observed between total dairy intake and prostate cancer risk, but this disappeared after eliminating the influence of calcium. Prostate specific antigen (PSA) screening, a marker for prostate cancer, has not been widely adopted in Finland. Therefore, a large proportion of cases in the study were detected as a result of clinical symptoms, which also lessened the possibility that the results were influenced by detection bias.