Risks and causes of myeloma
We don’t know what causes most cases of myeloma. But there are some risks factors that can increase your risk of developing it. These include being older, being overweight and having certain medical conditions.
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.
Being overweight or obese
The risk of myeloma is higher in people who are 
or . This is compared to people with a healthy body weight.
Age
As with most other cancers, the risk of myeloma increases as you get older. It is very rare in people under 40.
Monoclonal gammopathy of undetermined significance (MGUS)
Some people with myeloma already have a rare medical condition called MGUS. MGUS stands for monoclonal gammopathy of undetermined significance.
MGUS means there are too many large protein molecules (immunoglobulins) in the blood. Doctors often find MGUS by chance as it can show up in routine blood tests.
In most people MGUS doesn't cause any symptoms or need treatment.
MGUS does not usually need treatment. Some people with MGUS go on to develop myeloma, so your specialist or GP will see you regularly for check ups. About 1 out of 100 people with MGUS (1%) develop myeloma each year.
Family history
You have a higher risk of myeloma or MGUS if you have a close relative with myeloma or MGUS. A close relative means a parent, brother, sister or child. This is compared to people with no close family members with these illnesses.
It is not clear as to why there is an increased risk. We need more research to fully understand how family history affects your risk of myeloma. Myeloma is rare. It is unusual for a family to have more than one member of a family with myeloma.
Some medical conditions
An autoimmune condition called pernicious anaemia appears to increase the risk of myeloma and MGUS.
Gender
Myeloma is slightly more common in men than women. It's not clear why this is and there may be many factors involved including genetics and lifestyle.
Ethnicity
There is some evidence that myeloma is more common in Black people than in White people. It’s not clear why this is.
Other possible causes
Stories about potential causes are often in the media and 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.
