Pancreatic cancer can be difficult to treat
Taking vitamin D tablets could substantially reduce the risk of pancreatic cancer, research suggests.
US scientists found taking the tablets cut the risk of a disease, which has a poor prognosis in almost half of cases.
There are more than 3,600 new cases of pancreatic cancer in women and more than 3,500 in men in the UK each year. Surgery is not often effective.
Vitamin D was examined as it previously showed promise in cutting the risk of prostate, breast and colon cancer.
Except for smoking, no environmental factors or dietary factors have been linked to the pancreatic cancer.
But previous studies have suggested that vitamin D might help to block the proliferation of cancer cells.
And pancreas tissue - both normal and cancerous - has been found to contain high levels of an enzyme that converts vitamin D into its active form.
For the new study, which was led by Northwestern University in Illinois and features in Cancer Epidemiology Biomarkers & Prevention, researchers examined data on more than 120,000 people from two large, long-term health surveys.
Taking the US Recommended Daily Allowance (RDA) of vitamin D (400 IU/day) was found to reduce the risk of pancreatic cancer by 43%.
They said further work was necessary to determine if consuming vitamin D in the diet, or through sun exposure might have even more of an effect than taking supplements.
Vitamin D helps the body to form and maintain strong bones by encouraging the body to absorb calcium.
However, the researchers found no evidence of a link between risk of the cancer and calcium, or retinol, a vitamin which affects vitamin D's impact on calcium absorption.
Multi-vitamin supplements, often contain retinol.
Lead researcher Dr Hal Skinner said: "There is a growing body of information indicating that achieving higher levels of vitamin D through supplements, diet or prudent sun exposure may provide a range health benefits by preventing common chronic diseases."
More work needed
He said certain groups could be defined as being at higher risk for pancreatic cancer - for example cigarette smokers or those with a family history of the disease.
However, he said: "I would make no specific recommendation for vitamin D supplementation to prevent pancreatic cancer until we can carry out a trial to determine definitively who might benefit from such an intervention."
Henry Scowcroft, science information officer at the charity Cancer Research UK, said: "The results of this study don't mean that people should take vitamin D supplements to ward off pancreatic cancer, especially as vitamin D can be harmful in large quantities.
"As the authors themselves point out, this is the very first study to find any association between the disease and vitamin D intake.
"So this result needs to be repeated in other large studies, and scientists need to show exactly how vitamin D might prevent pancreatic cancer before we could issue any specific lifestyle advice."