The study followed 115,096 cases of breast cancer, colon cancer and prostate cancer diagnosed in people who lived in Norway between 1964 and 1992.
The study found the timing of cancer diagnosis was closely associated with prognosis of the disease. Patients diagnosed with breast cancer, colon cancer or prostate cancer during summer and fall were more likely to survive than those diagnosed during spring and winter.
People get more sun exposure, which meant that they had high levels of vitamin D3, during summer and fall. It is possible that elevated vitamin D at the time of diagnosis may play a role in the outcomes of breast cancer, colon cancer and prostate cancer.
The findings suggest that patients with breast cancer, colon cancer or prostate cancer could be better off taking vitamin D supplements or get lots of sun exposure during treatment.
Recent studies have found that high vitamin D can lower sexual hormones, which are known to promote hormone responsive cancers like breast cancer and prostate cancer or even colon cancer even though not all hormone-cancer relations are well understood.
Observational studies suggest that up to 17 types of cancer including breast cancer and prostate cancer have something to do with vitamin D deficiency. (David Liu)
Trude Eid Robsahm , Steinar Tretli, Arne Dahlback, Johan Moan, Vitamin D3 from sunlight may improve the prognosis of breast-, colon- and prostate cancer (Norway), Cancer Causes Control. 2004 Mar;15(2):149-58.
