Causes and risk factors for CML

The cause of CML is unknown, but research is going on to find out more.

There are a number of factors that might increase your risk of developing CML but, for most people, it isn’t clear why it develops. The known risk factors are listed below.


The risk of developing CML increases slightly with age.

Radiation exposure

Exposure to very high radiation levels is known to increase the risk of developing CML. For example, accidental exposure can happen after a nuclear accident like Chernobyl. Nobody in the UK is exposed to radiation levels high enough to increase their risk of developing CML. For most people with CML, there’s no obvious link to radiation exposure.

Sometimes there is publicity about an increase in leukaemia in people who live near nuclear power plants. Research is still going on to see whether there is a definite link, but at the moment there is no evidence of this. Research has also found no links between the risk of adults developing CML and:

  • exposure to electromagnetic fields
  • living near high-voltage electricity cables
  • household radon.

Like other cancers, CML is not infectious and cannot be passed on to other people.

Back to Diagnosing

Being diagnosed with CML

If your GP thinks you may have CML, they will refer you to a haematologist who will arrange more tests.