Updated Findings on Increased Cancer Occurrence in Sweden After 1986 Chernobyl Accident

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Researchers have uncovered an increased incidence of certain types of cancer in Sweden following the Chernobyl nuclear power plant accident, according to a novel study published by Tondel et al in Environmental Epidemiology.

Study Methods and Results

The Chernobyl accident in 1986 led to the spread of radioactivity across Sweden and Europe.

In the new longitudinal follow-up study, the researchers utilized new, more specific calculation methods to compare the calculated radiation doses from the soil and different foods in various organs with certain types of cancer across 2.2 million individuals residing in nine Swedish counties (Norrbotten, Dalarna, Södermanland, Jämtland, Västmanland, Gävleborg, Västerbotten, Uppsala, and Västernorrland) in 1986. These counties consist of individuals who received varying doses of radiation from the Chernobyl fallout—caused by ingestion of contaminated food and from the surface of the soil—and who were monitored by the National Cancer Register up until December 31, 2020. Previous follow-up analyses carried out in Sweden, the most recent of which was conducted in 2010, have shown a certain overall increase in all cancer types linked to the soil.

The researchers then adjusted for potentially influential factors such as underlying cancer incidence in the nine counties prior to the Chernobyl accident, living in urban or sparsely populated areas, education level, age, and gender.

The researchers discovered slightly increased incidences of colorectal cancer, pancreatic cancer, gastric cancer in male patients and an increased incidence of lymphoma in female patients. However, they noted that the increased risks were small and could not be translated to an individual risk. Therefore, they emphasized that caution may be needed when interpreting the epidemiologic results.


“[W]e have now developed and deployed a dose calculation program to be able to calculate the radiation doses in the various organs of the body from soil and food,” explained lead study author Martin Tondel, MD, PhD, a researcher of Occupational and Environmental Medicine in the Department of Medical Sciences at Uppsala University and the Uppsala University Hospital. “Proven connections do not mean that we can safely say that radiation is also the cause, but studies following nuclear accidents are very important in terms of gaining more knowledge about radiation and cancer and for developing research methods. For example, we have identified that a hunting lifestyle may have played a role in our results, which means that we will be able to draw even more reliable conclusions in future studies,” he concluded.

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