SAN FRANCISCOA new study supports the hypothesis that calcium
consumption is associated with a greater risk of prostate cancer.
June M. Chan, ScD, Department of Epidemiology, Harvard School of
Public Health, presented the results at the 91st Annual
Meeting of the American Association for Cancer Research (AACR).
Dr. Chan and her colleagues at Harvard and Brigham and Womens
Hospital studied the relationship between dietary calcium and
prostate cancer in the 20,885 men in the Physicians Health
Study. At the beginning of the study, the subjects filled out a brief
dietary questionnaire, which the investigators used to estimate their
consumption of five dairy products, including milk, cheese, and ice
cream. At 11 years of follow-up, 1,012 cases of prostate cancer were identified.
The results showed a moderate elevation in prostate cancer risk
associated with higher intakes of dairy products and dairy calcium,
adjusting for other risk factors such as age, smoking, exercise
levels, and body mass index.
The study also showed that men who drank more than six glasses of
milk a week had lower levels of vitamin D (1,25 dihydroxyvitamin D)
than men who drank fewer than two glasses of milk a week. The
researchers speculate that vitamin D may have protective effects on
For men concerned about prostate cancer, the study suggests a
little caution, but it is far too early to recommend any extreme
change in eating habits, Dr. Chan cautioned. More
research is needed to confirm these findings and to clarify the
underlying biological mechanisms.
She noted that some data suggest that calcium may play a role in
progression from local to metastatic disease. She and her colleagues
will continue to investigate the role of calcium in tumor growth.