Men Who Work Outdoors Less Likely to Get Kidney Cancer
In a study of over 2,500 people, researchers have found that men whose occupations exposed them to the greatest amount of sunlight were less likely to contract kidney cancer than men who worked indoors.
Sara Karami, PhD of the National Cancer Institute, and colleagues conducted the case control study between 1999 and 2003 in four Central and Eastern European countries, which are known for having some of the highest kidney cancer rates in the world. They collected demographic and occupational histories and associated their cancer status with their industry and job title.
Men whose jobs exposed them to the greatest amount of sunlight were at about a 24 to 38% lower risk for kidney cancer, also known as renal cell carcinoma. Men in higher latitudes, such as those living in Russia, who worked outside had an even greater advantage – a 71 to 73% lower risk.
Unfortunately, there was not a similar association noted with women. Researchers theorized that hormonal differences may play a role or that women are more likely to wear sunscreen when outdoors.
The hypothesis used by the researchers to explain the findings is that the skin uses sunlight exposure to produce vitamin D and the kidney is the major organ involved with vitamin D metabolism and calcium homeostasis. Recent studies have found that vitamin D may reduce the risk of several cancers. The researchers also noted a correlation between an increase in vitamin D deficiency and increased incidence of kidney cancer.
The authors caution against using the results of the study to abandon care when it comes to UV light and the sun as their research did not take into account any increased risk of skin cancers that could arise from excess sunlight exposure.
"Occupational sunlight exposure and risk of renal cell carcinoma." Sara Karami, Paolo Boffetta, Patricia Stewart, Nathaniel Rothman, Katherine L. Hunting, Mustafa Dosemeci, Sonja I. Berndt, Paul Brennan, Wong-Ho Chow, and Lee E. Moore. CANCER; Published Online: March 8, 2010 (DOI: 10.1002/cncr.24939).