Risks and causes of chronic lymphocytic leukaemia (CLL)

What is a risk factor?

Anything that can increase your risk of getting a disease is called a risk factor. Different cancers have different risk factors.­ Having one or more of these risk factors doesn't mean you will definitely get that cancer.

Risk factors for CLL

Age

Your risk of developing CLL increases as you get older. It is very rare in people younger than 40.

Sex

Men are more likely to develop CLL than women. We don't know why that is.

Family history

We know that there is some kind of ​inherited​ genetic change in some people with CLL. But most people with CLL do not have a family history of it. 

You have a higher risk of developing CLL if a close family member (parent, sibling, child) has CLL. But most people with a family history of CLL do not develop it themselves.

Where there isn't clear evidence

Some factors might increase the risk of CLL but there is not enough evidence to be sure.

Exposure to chemicals

Some studies suggest that certain hair dyes might increase the risk of developing CLL. But we need more research to clarify if hair dye use today increases the risk of CLL.

Living on a farm, or being exposed to herbicides and pesticides may be linked to an increased risk of CLL.

Other possible causes of CLL

There are often stories about potential causes in the media. It isn’t always clear which ideas are supported by evidence. There might be things you have heard of that we haven’t included here. This is because either there is no evidence about them or it is less clear.

Find out more about cancer myths

Reducing your risk

There are ways you can reduce your risk of cancer.

Find out more about reducing your risk