Myeloma risks and causes

Just under 4,800 people in the UK are diagnosed with myeloma each year. About 3 in every 200 cancers diagnosed (1.5%) are myeloma. The risk of myeloma increases as we get older and it is very rare in people under 40. But it is almost twice as common in black populations as it is in white and Asian populations. It is more common in men than in women.

A risk factor is anything that increases your risk of getting a disease. Different cancers have different risk factors. Even if you have one or more risk factors, it does not mean that you will definitely get that disease.

Recent studies show that almost everyone who has myeloma has a rare medical condition called monoclonal gammopathy of unknown significance (MGUS) first. MGUS means that there are too many large protein molecules known as immunoglobulins in the blood. MGUS is often found by chance because it can show up in routine blood tests. It doesn't cause any symptoms, and does not generally affect your health or need treatment. Some people with MGUS go on to develop myeloma, so if you have MGUS you will be asked to see a specialist regularly for check ups.

Studies show that people with a parent, brother, sister, or child with myeloma or monoclonal gammopathy of unknown significance (MGUS) are 2 or 3 times as likely to develop myeloma or MGUS compared to people with no close family members with these illnesses.

People who take medicines to lower immunity after a organ transplant may have 3 times the risk of myeloma compared to the general population. A review of published studies has shown that people with HIV have an increased risk of myeloma.

An autoimmune condition called pernicious anaemia appears to increase the risk of myeloma by a small amount. A type of chest infection called pneumonia may also increase the risk but this is unclear.

People who have had thyroid cancer may have an increased risk of myeloma. The increase may be due to the treatment for thyroid cancer. Or some of the risk factors that cause thyroid cancer may also cause myeloma.

Most evidence shows that people who are overweight or obese may have a slightly increased risk of myeloma compared to people with a healthy bodyweight. 

One study has shown that taller women may have a higher risk of multiple myeloma compared to shorter women. But another study did not show this, so it is unclear whether height influences myeloma risk.

Diet does not appear to have any effect on myeloma risk but evidence in this area is weak.

Some research has suggested that people in some jobs may have an increased risk of developing multiple myeloma because they are exposed to certain chemicals. But the International Agency for Research on Cancer (IARC) states that the evidence is limited overall. It has been suggested that people may have an increased risk if they work in the petrol or oil industry, farming, wood working, the leather industry, painting and decorating, hairdressing, rubber manufacturing or fire fighting. But there is no evidence to prove that any of these occupations carry an increased risk of myeloma.

Some studies in the past seemed to show that people exposed to high levels of radiation may have an increased risk of developing myeloma. A recent review found no strong evidence for this but the IARC states that there may be a link.

Studies with very small numbers of myeloma patients have indicated that using paracetamol (acetaminophen), insulin, a steroid called prednisone, or gout medicines may increase myeloma risk. Using statins (drugs used to lower cholesterol levels) or hormone replacement therapy (HRT) may reduce the risk of myeloma. But the studies are so small that these findings are not reliable.