Risk factors for chronic lymphocytic leukemia

A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes chronic lymphocytic leukemia (CLL) develops in people who don’t have any of the risk factors described below.

The risk of developing CLL increases with age. It usually occurs in people over the age of 50 years. More men than women develop CLL. It is also more common in people of Russian and European descent than people of Chinese, Japanese or Southeast Asian ancestry.

Risk factor

There is convincing evidence that a family history of CLL increases your risk for CLL.

Possible risk factors

The following factors have been linked with CLL, but there is not enough evidence to show for sure that they are risk factors. More research is needed to clarify the role of these factors for CLL.

  • coming into contact with pesticides through farming or other jobs
  • coming into contact with Agent Orange, a mixture of herbicides used during the Vietnam War
  • overweight or obesity
  • breathing in benzene

Questions to ask your healthcare team

To make the decisions that are right for you, ask your healthcare team questions about risks.

Expert review and references

  • American Cancer Society. What are the risk factors for chronic lymphocytic leukemia?. 2016: https://www.cancer.org/cancer/chronic-lymphocytic-leukemia/causes-risks-prevention/risk-factors.html.
  • Castillo JJ, Reagan JL, Ingham RR, Furman M, Dalia S, Merhi B, Nemr S, Zarrabi A, Mitri J. . Obesity but not overweight increases the incidence and mortality of leukemia in adults: a meta-analysis of prospective cohort studies. Leukemia Research. 2012.
  • International Agency for Research on Cancer (IARC). Volume 100D: Radiation: a review of human carcinogens. 2011: http://monographs.iarc.fr/ENG/Monographs/vol100D/mono100D.pdf.
  • Karakosta M, Delicha EM, Kouraklis G, Manola KN . Association of various risk factors with chronic lymphocytic leukemia and its cytogenetic characteristics. Archives of Environmental and Occupational Health. 2016.
  • Linet, M.S., Devesa, S.S., & Morgan, G.J. . The leukemias. Schottenfeld, D. & Fraumeni, J. F. Jr. (eds.). Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press; 2006: 44: pp. 841-871.
  • National Toxicology Program . 14th Report on Carcinogens . Department of Health and Human Services ; 2016 .
  • Saberi Hosnijeh F, Romieu I, Gallo V, Riboli E, Tjonneland A, Halkjaer J, et al . Anthropometric characteristics and risk of lymphoid and myeloid leukemia in the European Prospective Investigation into Cancer and Nutrition (EPIC). Cancer Causes and Control. 2013.
  • Wierda WC, O'Brien SM . Chronic lymphocytic leukemias. DeVita VT Jr, Lawrence TS, Rosenberg SA. Cancer: Principles and Practice of Oncology. 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2015: Chapter 110.

Reducing your risk for chronic lymphocytic leukemia (CLL)

You may lower your risk of developing chronic lymphocytic leukemia (CLL) by doing the following.