Can living in a colder climate increase your risk of cancer?

A new study has shown that populations native to extremely cold and high-altitude areas have a greater genetic predisposition to cancer as they age. And this is especially true with respect to lung, breast, and colorectal cancer.

This conclusion comes courtesy of the GLOBOCAN-2012 survey, which estimated cancer incidence across the world. The results of the survey demonstrate that, while prolonged cold led to evolutionary adaptive changes to help populations to survive in harsh conditions, it also appears to have interfered with their bodies’ cancer-preventing mechanisms.

Findings like these are what makes writing these e-letters so enjoyable for me — because in the process of reporting the latest in health to you, I often learn something, too. And today, I learned about something called “antagonistic pleiotropy.”

It’s a cancer hypothesis with roots in genetic evolution. Basically, the idea is that people are more likely to end up with genes predisposing them to disease, despite the fact that those same genes also offer a survival benefit.

In other words, it’s an evolutionary catch-22.

In this case, cells’ ability to resist frigid temperatures and high altitudes also increases the likelihood of cancer development. Analysis revealed that specific populations contain tumour suppressor genes. Study results showed that reduced apoptosis (the natural, normal process of cell death) is common and beneficial within individuals living in very cold and high-altitude environments. However, this helpful adaptation is also created from mutations of the tumour protein p53 (a protein responsible for tumour suppression), thus predisposing them to a higher cancer risk. (And yes, I know I’m getting a little “science-y” here, but p53 is a very important tumour protein and one you should know about anyway.)

Results showed that the link between cancer and extremely cold environments was most pronounced in Native Americans. (In this population, there were particularly significant associations with colorectal cancer.)

Similarly, Siberian Eskimos carried the most significant genetic links to colorectal, esophageal, lung, head and neck, breast, bladder, and blood cancers, as well as lymphoma.

Meanwhile, genetic mutations were most common among Greenland Inuits. And Tibetans and Andeans were found to have an equally staggering list of genetic links to cancer — running the gamut from squamous cell carcinoma to prostate cancer.

This survey certainly helps to explain why cancer and mortality rates are so much higher in certain geographic areas as compared to others. But it could also change the way doctors and scientists consider cancer’s origins. (As it stands, few consider genetic predisposition to be a significant factor, save for a few instances, like colorectal and breast cancer.)

It’s long overdue that we finally turn over every rock in this fight — because our current cut-burn-poison approach to addressing this dreaded disease is nothing short of barbaric. And to make matters worse, it’s not even particularly effective either.

To your good health,

Fred Pescatore, M.D.
Contributing Editor

Source:

medscape.com/viewarticle/889635