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Risk factors for leukemia

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes leukemia develops in people who don’t have any of the risk factors described below.

Men are more likely than women to develop leukemia. The risk for developing most types of leukemia increases with age.

Different types of leukemia have different risk factors. One risk factor may not increase the risk for all types of leukemia. Not all risk factors for the different types of leukemia are listed below.

Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.

Risk factors


Radiation therapy and chemotherapy




Family cancer syndromes

There is convincing evidence that the following factors increase your risk for leukemia.

High levels of radiation

Coming into contact with high levels of radiation – for example, radiation from nuclear reactor accidents – is a risk factor for leukemia.

Previous radiation therapy and chemotherapy

Radiation therapy given in the past to treat cancer or other health conditions increases the risk of leukemia. Chemotherapy given in the past to treat cancer also increases the risk. Having had both radiation therapy and chemotherapy to treat cancer increases the risk more than having had the individual treatments alone.


Smoking tobacco increases the risk of some types of leukemia, and it may increase the risk for other types.

Breathing in benzene

Benzene is found in unleaded gasoline and is used by the chemical industry. People may breathe in benzene at work or in the general environment or by using certain products. Benzene increases the risk of leukemia.

Breathing in formaldehyde

Some studies have shown that breathing in formaldehyde increases the risk of leukemia. Factory workers, chemical workers, embalmers and other people may come into contact with formaldehyde at work. Embalmers are at a higher risk of leukemia because they tend to have contact for a longer time and use more formaldehyde in their work.

Family cancer syndromes

Some conditions are linked to an increased risk of cancer, including leukemia, because of an inherited gene mutation (a change in the gene). These conditions are called family cancer syndromes or inherited (hereditary) cancer syndromes. Most family cancer syndromes are rare. Family cancer syndromes can lead to leukemia in both children and adults.

Possible risk factors

Overweight and obesity are possible risk factors for leukemia. This means that they have been linked with leukemia, but there is not enough evidence to show for sure that they are risk factors.

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about risks.

Down syndrome

A chromosome disorder caused by an extra chromosome 21. People with Down syndrome have a certain appearance with a flatter face, an upward slant to the eyes and a protruding tongue. People with Down syndrome have mild to moderate intellectual disabilities.

Down syndrome is associated with an increased risk of leukemia.

Also called trisomy 21 syndrome.

Fanconi anemia

An inherited condition that affects the bone marrow so it cannot make red blood cells, white blood cells or platelets.

Fanconi anemia increases the risk of myelodysplastic syndromes (MDS), acute myelogenous leukemia (AML), and oral and oropharyngeal cancers.


An inherited disease that affects the nervous system, immune system and other body systems. Signs and symptoms include loss of balance, poor coordination, frequent infections, red eye (due to widening of blood vessels) and abnormal eye movements.

Ataxia-telangiectasia is associated with an increased risk of some cancers, including leukemia and lymphoma.

Bloom syndrome

An inherited condition caused by mutations in a certain chromosome. Signs include shorter than average height, a high-pitched voice and a characteristic facial appearance.

Bloom syndrome is associated with an increased risk of cancer, including leukemia, lymphoma, breast, cervical, colon, stomach, laryngeal and non-melanoma skin cancers as well as Wilms tumour. People with Bloom syndrome often develop several different types of cancers.

Also called Bloom-Torre-Machacek syndrome or congenital telangiectatic erythema.