Leukemia

Causes & Risk Factors

No one knows the exact causes of leukemia. Doctors can seldom explain why one person gets leukemia and another does not. However, research has shown that people with certain leukemia risk factors are more likely than others to develop this disease. A leukemia risk factor is anything that increases a person’s chance of developing a disease.

Studies have found the following risk factors for leukemia:

  • Very high levels of radiation — People exposed to very high levels of radiation are much more likely than others to develop leukemia. Very high levels of radiation have been caused by atomic bomb explosions (such as those in Japan during World War II) and nuclear power plant accidents (such as the Chernobyl [also called Chornobyl] accident in 1986).

    Medical treatment that uses radiation can be another source of high-level exposure. Radiation used for diagnosis, however, exposes people to much lower levels of radiation and is not linked to leukemia.

  • Working with certain chemicals — Exposure to high levels of benzene in the workplace can cause leukemia. Benzene is used widely in the chemical industry. Formaldehyde is also used by the chemical industry. Workers exposed to formaldehyde also may be at greater risk of leukemia.

  • Chemotherapy — Cancer patients treated with certain cancer-fighting drugs sometimes later develop leukemia. For example, drugs known as alkylating agents are associated with the development of leukemia many years later.

  • Down syndrome and certain other genetic diseases — Some diseases caused by abnormal chromosomes may increase the risk of leukemia.

  • Human T-cell leukemia virus-I (HTLV-I) — This virus causes a rare type of chronic lymphocytic leukemia known as human T-cell leukemia. However, leukemia does not appear to be contagious.

  • Myelodysplastic syndrome — People with this blood disease are at increased risk of developing acute myeloid leukemia.

In the past, some studies suggested exposure to electromagnetic fields as another possible risk factor for leukemia. Electromagnetic fields are a type of low-energy radiation that comes from power lines and electric appliances. However, results from recent studies show that the evidence is weak for electromagnetic fields as a risk factor of leukemia.

Most people who have known risk factors do not get leukemia. On the other hand, many who do get the disease have none of the associated leukemia risk factors. People who think they may be at risk of leukemia should discuss this concern with their doctor. The doctor may suggest ways to reduce the risk and can plan an appropriate schedule for checkups.

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