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A risk factor is something that affects your chance of getting a disease, such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.

But having a risk factor, or even several risk factors, does not always mean that a person will get the disease, and many people get cancer without having any known risk factors.

There are some known risk factors for acute myeloid leukemia (AML).

Getting older

AML can occur at any age, but it becomes more common as people get older.

Being male

In general, l?eukemia is more common in men than women, including AML. The reason for this is not clear.

Smoking

The only proven lifestyle-related risk factor for AML is smoking. Many people know that smoking is linked to cancers of the lungs, mouth, and throat, but few realize that it can also affect cells that don’t come into direct contact with tobacco smoke. Cancer-causing substances in tobacco smoke are absorbed by the lungs and spread through the bloodstream to many parts of the body.

Being exposed to certain chemicals

The risk of AML is increased if you have been exposed to certain chemicals.

For example, long-term exposure to benzene is a risk factor for AML. Benzene is a solvent used in the rubber industry, oil refineries, chemical plants, shoe manufacturing, and gasoline-related industries, and is also found in cigarette smoke, gasoline and motor vehicle exhaust, and some glues, cleaning products, detergents, art supplies, and paints.

Some studies have linked AML risk to heavy workplace exposure to formaldehyde, but this link has not been seen in some other studies.

Being treated with certain chemotherapy drugs

Patients with cancer who are treated with certain chemotherapy (chemo) drugs are more likely to develop AML in the years following treatment.

Drugs called alkylating agents are linked to an increased risk of AML. Often a patient will get a disease called a myelodysplastic syndrome before the AML. Examples of alkylating drugs include cyclophosphamide, mechlorethamine, procarbazine, chlorambucil, melphalan, busulfan, carmustine, cisplatin, and carboplatin.

Chemo drugs known as topoisomerase II inhibitors are also linked to AML. AML linked to these drugs tends to occur without myelodysplastic syndrome developing first. Examples of topoisomerase II inhibitors include etoposide, teniposide, mitoxantrone, epirubicin, and doxorubicin.

Being exposed to radiation

High-dose radiation exposure (such as being a survivor of an atomic bomb blast or nuclear reactor accident) increases the risk of developing AML. Japanese atomic bomb survivors had a greatly increased risk of developing acute leukemia.

Radiation treatment for cancer has also been linked to an increased risk of AML. The risk varies based on the amount of radiation given and what area is treated.

The possible risks of leukemia from exposure to lower levels of radiation, such as from imaging tests like x-rays or CT scans, are not well-defined. Exposure to such radiation, especially very early in life, might carry an increased risk of leukemia, but how much of a risk is not clear. If there is an increased risk it is likely to be small, but to be safe, most doctors try to limit radiation exposure from tests as much as possible, especially in children and pregnant women.

For more information, see X-rays, Gamma Rays and Cancer Risk.

Having certain blood disorders

People with certain blood disorders seem to be at increased risk for getting AML. These include chronic myeloproliferative disorders such as polycythemia vera, essential thrombocythemia, and idiopathic myelofibrosis. The risk of AML increases if these disorders are treated with some types of chemotherapy or radiation.

Some people who have a myelodysplastic syndrome (MDS) may develop AML. Patients with MDS have low blood cell counts and abnormal cells in the blood and bone marrow. MDS can evolve over time into AML. AML that develops after MDS is often hard to treat.

Having a genetic syndrome

Some syndromes that are caused by genetic mutations (abnormal changes) present at birth seem to raise the risk of AML. These include:

• Fanconi anemia
• Bloom syndrome
• Ataxia-telangiectasia
• Diamond-Blackfan anemia
• Shwachman-Diamond syndrome
• Li-Fraumeni syndrome
• Neurofibromatosis type 1
• Severe congenital neutropenia (also called Kostmann syndrome)

Chromosomes are long strands of DNA (genes) inside our cells. Some chromosome problems present at birth are also linked to a higher risk of AML, including:

• Down syndrome (being born with an extra copy of chromosome 21)
• Trisomy 8 (being born with an extra copy of chromosome 8)

Having a family history

Although most cases of AML are not thought to have a strong genetic link, having a close relative (such as a parent, brother, or sister) with AML increases your risk of getting the disease.

Someone who has an identical twin who got AML before they were a year old has a very high risk of also getting AML.

Uncertain, unproven or controversial risk factors

Other factors that have been studied for a possible link to AML include:

• Exposure to electromagnetic fields (such as living near power lines)
• Workplace exposure to diesel, gasoline, and certain other chemicals and solvents
• Exposure to herbicides or pesticides

So far, none of these factors has been linked conclusively to AML. Research is being done in these areas.