Rachel Neale, Ph.D., from Australia's Queensland Institute of Medical Research led the population-based, case-control study, which adds to existing conflicting data about sun exposure, vitamin D gained from sun exposure and the risk of cancer. Neale's study results support existing ecological data, which suggests that sun exposure has a protective effect against pancreatic cancer.
"Several ecological studies, including one conducted in Australia, have suggested that people living in areas with high sun exposure have lower risk for pancreatic cancer. However, some studies of circulating vitamin D indicate that people with high vitamin D are at increased risk, and one study of vitamin D intake supports this increased risk."
The study was conducted between 2007 and 2011 and involved 714 Australians from Queensland, who were matched to 709 controls in terms of age and sex. The team questioned all participants regarding their socio-demographic information and medical history, as well as about their birth location, history of skin cancer and skin type in terms of skin color, risk of sunburn sunburn and tanning ability.
The team then assigned the appropriate ultraviolet radiation level to each birth location using NASA's Total Ozone Mapping Spectrometer, and divided them into three categories based on the level of radiation.
They found that the risk for pancreatic cancer was 24% lower in those born in areas with the highest levels of ultraviolet radiation as compared with those born in areas of low ultraviolet radiation.
Despite the fact that all skin types have a considerable link of being at risk for pancreatic cancer, they discovered that those with the most sun-sensitive skin had a 49% lower risk than those with the least sun-sensitive skin. In addition, the risk of pancreatic cancer was 40% lower in participants with a history of skin cancer or other sun-related skin lesions compared with those who had not reported skin lesions.
"There is increasing interest in the role of sun exposure, which has been largely attributed to the effect of vitamin D, on cancer incidence and mortality. It is important that we understand the risks and benefits of sun exposure because it has implications for public health messages about sun exposure, and possibly about policy related to vitamin D supplementation or food fortification."
Neale suggests that large cohort studies are needed in the future, which measure sun exposure and vitamin D levels more comprehensively. She concludes: "There are several trials of vitamin D that are either under way or planned, and pooling data from these might give some clue about vitamin D and pancreatic cancer."