Researchers at the University of California, San Diego School of Medicine are reporting that living in a city with lots of cloud cover may be associated with risk for pancreatic cancer.
The report was recently published in the Journal of Steroid Biochemistry and Molecular Biology and stated that pancreatic cancer rates are highest in countries with the least amount of sunlight. Low sunlight levels were due to a combination of heavy cloud cover and high latitude.1
Researchers analyzed the association between cloud-adjusted ultraviolet B (UVB) irradiance and age-standardized incidence rates of pancreatic cancer. They found that the lower the cloud-adjusted UVB irradiance, the higher the incidence rate of pancreatic cancer.
“There was 8 times higher age-adjusted incidence rate of cancer in countries with the lowest solar UVB radiance compared to countries with the highest,” said lead study author Cedric Garland, DrPH, who is an adjunct professor in the Department of Family Medicine and Public Health and member of UC San Diego Moores Cancer Center, San Diego.
“Such a high hazard ratio when found in epidemiology almost always denotes causation by the factor of interest. It is similar to that for smoking and lung cancer.”
He and his colleagues studied data from more than 100 countries, taking into account international differences and possible confounders, such as alcohol consumption, obesity, and smoking.
Garland and his team have previously shown that sufficient levels of a metabolite of vitamin D in the serum, known as 25-hydroxyvitamin D was associated with substantially lower risk of breast and colorectal cancer.
The current paper is the first to implicate vitamin D deficiency with pancreatic cancer. He said these findings have clinical implications for oncologists.
“25-hydroxyvitamin D (25(OH)D) will prevent many future malignancies and definitely is associated with better survival of patients with breast, colorectal, and pancreatic cancer. So oncologists should always measure the serum 25(OH)D and raise it to no less than 80 ng/ml to 90 ng/ml in their patients with any of these cancers,” Garland told Cancer Therapy Advisor.
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“Contraindications include hypercalcemia and active sarcoidosis, tuberculosis, other granulomatous diseases, some granulomas may metabolize 25(OH)D to 1,25(OH)2D. The serum 25(OH)D and calcium concentrations should be measured monthly in cancer patients until their cancer is under control, then at least annually, preferably in February or March, when 25(OH)D concentrations are lowest in the northern hemisphere. The benefits of high 25(OH)D in cancer patients are so high that any minimal risks are worth taking.”
He said the main risk is a slight increase in kidney stones, but some studies have found no increase in kidney stones or any other health condition with oral intakes below 10,000 IU/day.