No one knows the exact causes of chronic lymphocytic leukemia (CLL); however, doctors have identified certain risk factors for developing this form of leukemia. While not causes of chronic lymphocytic leukemia, these risk factors increase a person's chances of developing the disease. These risk factors include having a family history of chronic lymphocytic leukemia or cancer of the lymph system; being middle-aged or older, male, or Caucasian; and having relatives who are Russian Jews or Eastern European Jews.

Chronic lymphocytic leukemia (CLL) is a type of cancer in which the bone marrow makes too many lymphocytes (a type of white blood cells). Chronic lymphocytic leukemia is the second most common type of leukemia in adults, accounting for about 7,000 new cases of leukemia each year. In most cases, chronic lymphocytic leukemia occurs during or after middle age; CLL rarely occurs in children. Chronic lymphocytic leukemia usually progresses slowly.
 
Specific Causes of Chronic Lymphocytic Leukemia
No one knows the exact causes of chronic lymphocytic leukemia. Doctors can seldom explain why one person will get chronic lymphocytic leukemia and another person will not. However, leukemia research has shown that people with certain risk factors are more likely than others to develop chronic lymphocytic leukemia. A risk factor is anything that increases a person's chances of developing a disease.
 
Causes of Chronic Lymphocytic Leukemia: Know the Risk Factors
__Being middle-aged or older, male, or Caucasian
__A family history of chronic lymphocytic leukemia or cancer of the lymph system
__Having relatives who are Russian Jews or Eastern European Jews.