Abstract PL04-05: Vitamin D: Panacea or a Pandora's box for prevention?

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Abstract Widespread interest in the possible preventive role of vitamin D against cancer emerged from ecological studies of the association between latitude and cancer mortality, in-vitro studies of the effects of vitamin D on proliferation and apoptosis, and presence of vitamin D receptors in many tissues. Observational studies of colorectal cancer provide the most promising data supporting a potential preventive benefit for vitamin D but this effect, so far, is not supported by results from randomized trials. Observational studies for other common cancers such as prostate and breast provide little support for a significant preventive effect of vitamin D. The Cohort Consortium Vitamin D Pooling Project of Rarer Cancers (VDPP) is a consortial effort including 10 prospective cohorts from the United States, Finland and China to examine the association between concentrations of 25-hydroxyvitamin D (25(OH)D) and risk of seven types of rarer cancers: endometrial, esophageal, gastric, kidney, non-Hodgkin's lymphoma, pancreatic and ovarian. No associated benefit, and potential harms, were observed including confirmation of prior reports of an increased risk of pancreatic cancer with higher concentrations of 25(OH)D. The association between mortality and 25(OH)D concentrations was examined in the Third National Health and Nutrition Examination Survey (NHANES III). The mortality rate ratio was statistically significantly higher for those with vitamin D concentrations in the deficient range, defined as <45nmol/L. Among women, an increased rate of mortality was observed both for deficient concentrations and very high concentrations (>124nmol/L). Results suggest that caution should be exercised in using very high dose vitamin D supplementation in prevention trials that may result in high concentrations of vitamin D (>100nmol/L). Citation Information: Cancer Prev Res 2010;3(1 Suppl):PL04-05.