A risk factor is anything that increases a person's chance of getting a disease such as cancer. Risk factors are either lifestyle-related, environmental, or genetic (inherited).

Lifestyle-related risk factors for some types of cancer include such things as smoking or unprotected exposure to strong sunlight. At this time there are no known lifestyle-related risk factors for acute lymphocytic leukemia.

Environmental risk factors are influences in our surroundings such as radiation, chemicals, and infections. Only radiation exposure (such as being a survivor of an atomic bomb blast or nuclear reactor accident) has been linked to ALL.

There is conflicting evidence about electromagnetic field (EMF) exposure (such as that occurring near very high-voltage power lines) as a potential risk factor for developing leukemia. The US National Cancer Institute has several large studies going on now to look into this question. Most studies published so far suggest either no increased risk or a very slightly increased risk. Clearly, most cases of leukemia are not related to EMF exposure.

Infection with the human T-cell lymphoma/leukemia virus (HTLV-1) can cause a rare type of acute lymphocytic leukemia. Most cases occur in Japan and the Caribbean area, and this disease is not common in the United States. Burkitt lymphoma, a disease more common in Africa, can form a type of acute lymphocytic leukemia. It has been linked to infection with the Epstein-Barr (EB) virus (the virus that causes infectious mononucleosis, or "mono").

Acute lymphocytic leukemia does not appear to be an inherited disease, although some syndromes with a genetic basis, such as Down syndrome, seem to raise the risk.

ALL is more common in whites than in African Americans, and is slightly more common in males than in females, although the reasons for this are not clear.

Revised 5-04