More Prostate Cancer in Colder Climes

There’s a north-south pattern for the occurrence of prostate cancer – it’s more frequent in the northern part of the USA.  The north is colder, with lower, and people living there have lower blood levels of vitamin D.  Idaho State University researchers have investigated this connection further, and reported online in the International Journal of Health Geographics.  They believe there must be another factor, additional to vitamin D, that’s responsible for the climatic variation in distribution.

Information on prostate cancer was obtained for each US county, along with meteorological parameters such as air temperature, snowfall, rainfall, humidity, the use of pesticides, and the amount of land used for crops.   The scientists confirmed that colder and drier counties had a higher incidence of prostate cancer, even after adjusting for snowfall and reported pesticide use.  However, in the counties with a high average snowfall, the amount of land used for crops (and therefore higher pesticide use) was associated with the frequency of prostate cancer.

It’s known that temperature, humidity, snow and rainfall affect the deposition, absorption, and degradation of persistent organic pollutants, including pesticides.  The scientists removed the possible role of UV radiation from the analysis, and still found a correlation between the likely amounts of pesticide residues and the occurrence of cancer.  Clearly further investigations are necessary to establish more specific carcinogenic culprits; in the meantime, better awareness of the risks of pesticide application is necessary.