Causes
of Leukemia
No one knows the exact causes of leukemia. Doctors can seldom explain why one
person gets this disease and another does not. However, research has shown that
people with certain risk factors are more likely than others to develop
leukemia. A 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.
Most people who have known risk factors do not get leukemia. On the other
hand, many who do get the disease have none of these 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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