Higher background radiation levels lead to lower levels of lung, pancreatic and colon cancers in both American men and women as well as lower rates of brain and bladder cancers in men, according to a new study by BGU and Nuclear Research Center Negev (NRCN) scientists. With higher radiation levels, life expectancy increased. Their findings were published recently in Biogerontology.
Using the United States Environmental Protection Agency's radiation dose calculator, the researchers retrieved data about background radiation from all 3,129 US counties. The data about cancer rates was retrieved from the United States Cancer Statistics. The data about life expectancy was retrieved from the Institute for Health Metrics and Evaluation at the University of Washington Medical Center.
Background radiation is an ionizing radiation that exists in the environment from natural sources. It includes radiation coming from outer space, and radiation from terrestrial sources. Across the US, background radiation fluctuates between 92 to 227 millirem per year. A millirem is one thousandth of a Roentgen Equivalent Man (REM), which is a measure of the health effect of low-level ionizing radiation on the human body. Since the 1960's, there has been a linear no-threshold hypothesis guiding policy that any radiation is bad. As a result, hundreds of billions of dollars are spent around the world to reduce radiation levels as much as possible.
However, according to BGU’s Profs. Vadim Fraifeld (pictured above) and Marina Wolfson, and Dr. Elroei David of the Nuclear Research Center Negev, they found lower levels of several types of cancers when the radiation levels were on the higher end of the spectrum rather than on the lower end. Among both men and women, there was a significant decrease in lung, pancreatic, colon and rectal cancers. Among men, there were additional decreases in brain and bladder cancers. There was no decrease in cervix, breast or prostate cancers or leukemia.
"All in all, it is reasonable to suggest that a radiation threshold does exist, yet it is higher than the upper limit of the natural background radiation levels in the US (227 mrem/year)," the researchers write.
