Gender: Men are more likely to develop CML, CLL and AML than women.
Age: The risk of most leukemias, with the exception of ALL, typically increases with age.
Family history: Most leukemias have no familial link. However, first degree relatives of CLL patients, or having an identical twin who has or had AML or ALL, may put you at an increased risk for developing the disease.
Genetic diseases: Certain genetic abnormalities, such as Down syndrome, may play a role in the development of leukemia.
Smoking: Although smoking may not be a direct cause of leukemia, smoking cigarettes does increase the risk of developing AML.
Exposure to high levels of radiation: Exposure to high-energy radiation (e.g., atomic bomb explosions) and intense exposure to low-energy radiation from electromagnetic fields (e.g., power lines).
Chemical exposure: Long-term exposure to certain pesticides or industrial chemicals like benzene is considered to be a risk for leukemia.
Previous cancer treatment: Certain types of chemotherapy and radiation therapy for other cancers are considered leukemia risk factors.