Avoiding direct exposure to sunlight is generally seen as a good way of reducing skin cancer risk. However, Chinese scientists demonstrated that death rates in China (as in the West) from several major cancer are lower among people with more ambient UVB radiation. The same is true for some other cancers, including those of the cervix, rectum, colon, stomach and esophagus.
Survey results of the study led by Wanqing Chen suggest that the sunshine vitamin that the body creates naturally in response to ultra violet rays might lower the incidence rates or improve the outcomes of cancer amongst the Chinese population. The findings also demonstrate that industrialization and a lack of sun exposure go hand in hand.
To estimate the prevalence of cancer, the team assessed cancer mortality data in a sample of 263 Chinese counties from 1990 to 1992 and from the national cancer registration data from 1998 to 2002. To estimate the average daily irradiance for the 263 counties in 1990, the team used satellite measurements of cloud-adjusted ambient UVB intensity.
Ad Brand from the Sunlight Research Forum (SRF), that helps to promote the latest medical and scientific information on the effects of moderate UV exposure on man, explains:
“Under the influence of UVB radiation over 90 percent of vitamin D needed by the body is formed in the skin. Because of the scientifically verified positive effect of high vitamin D levels (40 to 60 nanograms per milliliter of blood are optimal) the SRF recommends a regular, but moderate exposure to UVB irradiance – either in the sun or under a solarium”.
Written by Petra Rattue