Risk Factors

A risk factor is anything that increases a person’s chance of developing cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health care choices.

The cause of CLL is unknown. There is no evidence indicating that exposure to radiation, chemicals, or chemotherapy increases a person’s risk of developing CLL. The following factors may raise a person’s risk of developing CLL:

Family history. Approximately 20% of people with CLL have a relative with CLL or some other lymph-related cancer. In order to learn more about the familial pattern that occurs in some patients, a registry of such families has been established at the National Cancer Institute.

Age. CLL is most common in older adults, is rare in young adults, and virtually never occurs in children. About 90% of people diagnosed with CLL are over age 50.

Gender. CLL occurs more frequently in men.

Ethnicity. B-cell CLL is more common in people of Russian and European descent, and virtually never occurs in people from China, Japan, or Southeast Asian countries. The reason(s) for this geographic difference is not known.

Agent Orange. The U.S. Department of Veterans Affairs lists CLL as a disease associated with exposure to Agent Orange, a chemical used during the Vietnam War.