How the Chernobyl nuclear accident affected thyroid health

Photo: Yves Alarie/Unsplash. Design: BOOST Thyroid.

Photo: Yves Alarie/Unsplash. Design: BOOST Thyroid.

The state of Hashimoto’s and thyroid conditions 30 years after the radioactive spillage

On April 26th 1986, one of the reactors at the Chernobyl Nuclear Power Plant exploded. One of the nuclear power plant reactors blew up, releasing large amounts of radiation into the atmosphere. Over 100 radioactive elements were scattered over parts of Ukraine, Belarus, Russia, and a wide area of Europe (1, 2). Because of the massive contamination, 200,000 people were evacuated and the area around the nuclear plant is unlivable (1).

An increase in thyroid disorders was one of the most common health problems in areas affected by the Chernobyl radioactive fallout (3).

Radioactive fallout

The explosion at the Chernobyl Nuclear Power Plant was powerful—about 400 times stronger than the Hiroshima atomic bomb (1). It released close to 2 EBq (2000000000000000000 Bq) worth of radioactivity in the air. In a medical context, a maximum therapeutic dose of iodine-131 used in clinics is 7.4 GBq (7400000000). This means the dose of Chernobyl radiation was about 270000000x higher than a therapeutic dose for cancer treatment (1, 4, 5).

Three main radioactive elements were released from the Chernobyl disaster (the halflife is the time it takes for one half of the radioactive elements to disintegrate):

Iodine-131: with a halflife of 8 days, known to lead to thyroid problems.

Strontium-137: with a halflife of 29 years, can cause leukemia.

Cesium-90: with a halflife of 30 years, can harm the entire body—especially the liver and spleen.

Radioactive iodine and the thyroid

Radioactive iodine (I-131) is a by-product of energy production in a nuclear reactor. In the case of the Chernobyl disaster, when I-131 was released in the air it got into the human body through breathing it in, eating contaminated leafy vegetables, or drinking contaminated milk (from cows and goats grazing contaminated grass) (6).

With such an intake, up to a third of all of the radioactive iodine in the body will end up in the thyroid gland. As radioactive iodine decays, it emits radiation and affects the thyroid and the nearby tissue. This process destroys thyroid cells as well as the surrounding capillaries preventing blood supply with oxygen and food. As a result, there are a lot of dying cells that start producing molecules triggering inflammation, this attracts immune cells to the thyroid.

As a consequence, immune cells flock to the thyroid gland to clean up the dead cells. Among the cell debris are parts of TPO and Tg. The entire site of the cell debris becomes inflamed, thus immune cells start their cleanup and from that point on they have a memory of TPO and Tg protein sequences and will attack them as an enemy for years to come (7, 8).

Even though the iodine-131 halflife is short, it was released in high doses from the destroyed nuclear reactor in Chernobyl for about 40 days after the accident. It took about seven months for it to decay to a safe level of radiation, this amount of time was enough to cause problems for thyroid health for years to come (2).

After the Chernobyl disaster, an increase in thyroid nodules elevated anti-TPO and anti-Tg antibodies. More underactive thyroid cases were reported in people living in the most affected areas of Ukraine, Belarus, and Russia (9). Exposure to radioactive fallout from Chernobyl caused a big increase in the number of cases of childhood and adult thyroid cancer in Ukraine, Belarus, and a part of Russia (4, 10 - 12).

Chernobyl and Hashimoto’s

Several reports have shown an increase in anti-TPO and anti-Tg antibodies in people most severely affected by the radioactive fallout. This increase seems to be transient, lasting for a period of up to 15 years. After which it seems the immune system resets, no antibodies are detected, and it’s likely the thyroid gland is no longer attacked (13-18).

Research shows how thyroid health developed in the 30 years after the Chernobyl accident. Many researchers noted autoimmune reaction changes through time and people that were exposed to radiation should be checked throughout the years to see the dynamics of radiation-caused autoimmune response.

Radioactivity doesn’t only turn the immune system against the thyroid, it changes how the immune system interacts with the entire body. It causes long-term inflammation that can severely damage, or even destroy some organs (19-23).

What may help?

Avoiding areas of high radioactivity is the best option, but sometimes—like in the case of the Chernobyl of Fukushima disasters—this isn’t possible.

Potassium iodine (KI) is considered the most effective preventive radiation management when exposed to high doses of iodine-131 radiation (24, 25). Potassium iodine prevents iodine-131 from becoming a building block of T4 and T3 hormones (26, 27). A single dose of potassium iodine helps for 24-36 hours (28-30). Newborn babies and elderly people might experience some side effects of potassium iodine, including upset stomach, digestive problems, rashes, and inflammation (31).


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