Acute Lymphocytic Leukemia - Risk Factors

Risk Factors

ALL in Children. In 2006, experts estimated that about 3,930 cases of acute lymphocytic leukemia would be diagnosed in the U.S., with about 2,630 of them in children and adolescents younger than age 20. Until recently, most studies listed it as the most common childhood cancer. (Some recent evidence suggests that cancers in the central nervous system may be surpassing ALL in children.) The disease typically develops in children ages 1 - 10 years old, but the disease can strike from infancy to old age.

ALL in Adults. About 30% of ALL cases occur in adults. Adults who develop ALL are usually male and over 50 years old, with the highest risk being above age 70. Risk is lowest between the ages of 25 - 50.

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Ethnicity and ALL

Caucasian and Asian children have a much higher risk for ALL than African American children, although African-American and Hispanic children who develop it do not appear to fare as well. Socioeconomic factors and unequal access to healthcare may account for some of these differences.

Hereditary Disorders

Certain inherited disorders can increase the risk for leukemia. For example, children with Down syndrome have a 20-times greater risk of developing ALL than the general population. Other rare genetic disorders associated with increased risk include Bloom syndrome, Fanconi's anemia, ataxia-telangiectasia, neurofibromatosis, Shwachman syndrome, IgA deficiency, and congenital X-linked agammaglobulinemia.

People Exposed to Radiation

Children treated with radiation and chemotherapy for Hodgkin's disease are at higher risk for acute leukemia within 2 - 13 years after treatment (usually of the myeloid variety). Children under age 10 are most susceptible to acute leukemia following exposure to radiation treatments. Susceptibility decreases between the ages of 10 - 19 then increases slowly again through age 50. After 50, a person is again at high risk of developing acute leukemia following ionizing radiation.

Most people who are not treated for cancer have low exposure to radiation, so radiation from other sources is not a significant cause of leukemia. However, fetal exposure to diagnostic x-rays (not ultrasound) before birth increases the danger of developing ALL by the age of 15 years.