Causes, Incidence, and Risk Factors of CLL

CLL is the second most common form of leukemia affecting adults in the United States, with approximately 10,000 new cases annually.⁵ CLL occurs more often in men than in women and is most often diagnosed in older adults.⁶

CLL is the result of an error within the DNA or genetic material of a single lymphocyte-forming cell that makes the cell become cancerous. How this occurs and why the body does not get rid of this defective cell is still unknown.² However, certain people have been shown to have a greater risk for CLL.

Older people are most vulnerable to CLL, as it usually occurs in those aged 55 years and older.⁶ Unlike other leukemias, CLL has not been shown to be linked to exposure to radiation or cancer-causing chemicals.

In America, there is not much difference between the rates of CLL in the Caucasian and African American populations, but those of Chinese, Japanese, Filipino, Hispanic, and Native American origin are much less likely to develop CLL.⁶

First-degree relatives of patients are somewhat more likely to get the disease than the general population.⁷ This suggests that, at least in some cases, there is an inherited predisposition to develop CLL.