Sun exposure Information by Marc Sorenson, EdD. Sunlight Institute.
There are 62,700 cases of kidney cancer and 14,240 deaths annually. Kidney cancer incidence has tripled since the early 1980s, and some researchers have felt that environmental factors may have played a part in that worrisome increase. One of those factors may be sun exposure, which may be vital to the prevention of the disease. The newest research measured sun exposure, which was based on the average number of hours per day outdoors in the summer, during different periods of life. The researchers also took into consideration the age of the subjects and adjusted the data for other factors that may associate to kidney cancer.
These were some of the research results:
- Higher summer sun exposure at age 40+ years, but not at younger ages, was associated with a significantly lower risk of thyroid cancer. When comparing the highest quartile (fourth) of sun exposure to the lowest quartile, there was a 44% reduction in risk.
- Average lifetime sun exposure was not associated with thyroid-cancer risk.
- Recent summer sun exposure was closely associated with a decreased risk of thyroid cancer.
One of the salient points, in my mind, is that the best sun exposure is that which is habitual or consistent. In the case of kidney cancer, sun exposure in the past does not indicate that the disease will be avoided in the future. Only recent sun exposure provides protection. However, this is not necessarily true of other diseases; in the case of breast and prostate cancers, childhood sun exposure is associated with a lesser risk of the diseases in adulthood.
Previous research has also confirmed the importance of sun exposure on kidney-cancer prevention. There is a strong inverse correlation between sun exposure and kidney cancer. For example, one study that used NMSC as a measure of sun exposure, determined that sun exposure reduced the risk of several cancers, including kidney cancer, from 35% to 42%. Kidney cancer mortality rates were found to be strongly inversely correlated with solar UVB doses in Dr. William Grant’s 2002 and 2006 ecological studies. 
Recent research by Dr. Sara Karami and colleagues, demonstrates that in women, there is a significant reduction in kidney cancer with high levels of sun exposure. Those women with the highest fourth of sun exposure showed a 33% reduction in risk. Interestingly, the data was adjusted for vitamin D intake, and the results still showed sun exposure to have a stand-alone protective influence on kidney cancer—another indication that sun exposure has protective effects beyond vitamin D production.
Remember that a lifetime habit of non-burning sun exposure will always provide the best health outcomes.
 Rachel D Zamoiski, Elizabeth K. Cahoon, D. Michal Freedman, et al. Prospective study of ultraviolet radiation exposure and thyroid cancer risk in the United States. Cancer Epidemiol Biomarkers Prev Published Online First December 2, 2016.
 Tuohimaa P, Pukkala E, Scélo G, Olsen JH, Brewster DH, Hemminki K, Tracey E, Weiderpass E, Kliewer EV, Pompe-Kirn V, McBride ML, Martos C, Chia KS, Tonita JM, Jonasson JG, Boffetta P, Brennan P. Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: vitamin D as a possible explanation. Eur J Cancer 2007;43(11):1701-12
 Grant WB. An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation. Cancer. 2002 Mar 15;94(6):1867-75.
 Grant WB, Garland CF. The association of solar ultraviolet B (UVB) with reducing risk of cancer: multifactorial ecologic analysis of geographic variation in age-adjusted cancer mortality rates. Anticancer Res. 2006 Jul-Aug;26(4A):2687-99.
 Karami S, Colt JS, Stewart PA, Schwartz K, Davis FG, Ruterbusch JJ, Chow WH, Wacholder S, Graubard BI, Purdue MP, MooreLE. Short Report: A case-control study of occupational sun exposure and renal cancer risk. Int J Cancer. 2015 Oct 27.
By Marc Sorenson, EdD. Sunlight Institute…
Canada has a long season each year in which vitamin D from sunlight is not available. Due to the northern latitude of Canada, May through October is the only period when vitamin D can be produced in response to sun exposure to the skin. Therefore, a new press release from the Vitamin D Society recommends to protect health by building up vitamin D during the summer. Vitamin D from the summer sun helps to prevent serious diseases such as cancer, cardiovascular diseases, diabetes, multiple sclerosis and others.
Dr. Reinhold Vieth, the scientific advisor for the Society, states the following: We often assume that the health benefits of sunshine are solely due to vitamin D, but that is not proven yet. In other words, it is likely that sunshine does more for our bodies than just produce vitamin D.”
Dr. Vieth is correct. Vitamin D is only one of several products of sun exposure. Others are nitric oxide, which helps prevent vascular problems, and serotonin and endorphins that enhance mood. It is likely that there are many more products of sun exposure that enhance human health.
The Society recommends 6 guidelines for safely enjoying the sun and its health benefits:
- Be moderate, and don’t burn.
- Sun exposure can produce vitamin D only during the mid-day hours, so be outside between 10 AM and 4 PM.
- Know your skin type and risk of burning. Red hair and very light skin predict a greater risk of burning. (Also remember that dark skin needs more sun exposure to produce vitamin D).
- A gradual build-up of a tan protects the skin from burning.
- When the skin begins to redden, it is time to stop the sun exposure.
- Frequent but shorter sun exposure times are better for producing vitamin D.
Since about 35% of all Canadians do not meet suggested vitamin D requirements, sun exposure is essential to reverse that statistic.
So Canadians, safely enjoy the sun this summer!
To read the entire press release, go to this link: http://www.vitamindsociety.org/press_release.php?id=44