Chernobyl Has Continuing Thyroid Impact in the Region

1986 Accident Has Increased Rates of Thyroid Cancer and Thyroid Disease

Chernobyl plant in sarcophagus
The nuclear accident at Chernobyl continues to have an impact on thyroid health in the region. Daniel Berehulak / Getty Images News

On April 26th, 1986, the worst nuclear accident in history took place in the small town of Chernobyl, located in the Ukraine region of the former Soviet Union. (The more recent Japanese nuclear crisis at Fukushima resulted in fewer deaths and significantly less radiation release than Chernobyl.)

About the Chernobyl Accident

The Chernobyl nuclear plant, located approximately 80 miles north of Kiev, experienced a chain reaction explosion that blew off the reactor's lid, releasing dangerous radiation.

More than 30 people were killed immediately, and in the ten days after the accident, clouds of deadly radioactive materials were released into the atmosphere, exposing the people of Chernobyl to radioactivity levels estimated to be 100 times greater than the Hiroshima bomb.

Radiation also traveled downwind, exposing Eastern Europeans to high levels of radiation, and contaminating food supplies that then affected other areas of Europe as well.

The radioactive materials released during the Chernobyl contained high levels of radioactive iodine, a material that accumulates in the thyroid gland. People, especially children, in heavily contaminated areas, which included Belarus, Ukraine, and other areas of Eastern Europe, were heavily exposed to these iodines (particularly iodine-131, with a half-life of 8 days) via food, primarily contaminated milk, and also via breathing the radioactive clouds.

Chernobyl Thyroid Statistics

Here are some startling statistics.

  • The cancers affecting those exposed to Chernobyl fallout tend to be more aggressive.
  • Prior to Chernobyl, thyroid cancer in children was almost non-existent. Starting in 1990, however, there was a dramatic increase in childhood thyroid cancers in Belarus, Ukraine, and to a lesser extent, Russia.
  • The most dramatic rate increase of thyroid cancer is in children who were 10 or younger when the Chernobyl accident occurred, and most specifically, those who were under 4.
  • In Ukraine, the incidence of thyroid cancer in children rose 10-fold in children who lived in that region.
  • Researchers found that in certain parts of Belarus, almost 40 percent of children who were under four when the accident occurred have developed or will develop thyroid cancer. This rate is higher than earlier estimated, and is far above the rates for those exposed to radiation in other parts of the world. Researchers believe this high rate may be due to iodine deficiency in that geographic region.
  • Among children living in Belarus, thyroid cancer is even more common and more severe in those who were younger than 2 years old at the time of the 1986 accident. Researchers believe that the rapid cellular growth that occurs in children under 2 facilitated a quicker and broader development of the cancer.
  • The incidence of thyroid cancer was 45 times greater among those who received the highest radiation dose as compared to those in the lowest-dose group.

Chernobyl: The Good News

There is some good news. The rates of thyroid cancer in children in the affected countries have decreased, and are now just slightly above the levels prior to the Chernobyl accident.

Still, experts caution that those exposed as children to radioactive iodine due to the Chernobyl nuclear explosion are more likely to develop hypothyroidism later in life. Researchers have shown that exposure to Chernobyl's radiation caused higher antithyroid antibodies, which are manifesting -- or may later manifest -- as overt hypothyroidism.


Pacini F, et. al. "Thyroid consequences of the Chernobyl nuclear accident." Acta Paediatr Suppl. 1999 Dec;88(433):23-7

Demidchik, Yuri, et. al. "Childhood thyroid cancer in Belarus, Russia, and Ukraine after Chernobyl and at present." Arq Bras Endocrinol Metab vol.51 no.5 São Paulo July 2007

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