Myeloma risks and causes

Around 4,500 people in the UK are diagnosed with myeloma each year. About 3 in every 200 cancers diagnosed (1.5%) are myeloma. Risk of myeloma increases with age - it's very rare in people under 40. But it is twice as common in black populations as it is in white populations.

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.

A review of published studies has shown that people with HIV or AIDS and people who take medicines to prevent rejection after an organ transplant have three times the risk of myeloma compared to the general population.

People who have a rare medical condition called monoclonal gammopathy of unknown significance (MGUS) have a higher risk of developing myeloma than other people. Around 20 to 30 out of every 100 people diagnosed with MGUS (20 to 30%) will get multiple myeloma eventually. Recent studies show that almost everyone who develops myeloma has MGUS first.

Some studies show a higher risk of myeloma in people who have diabetes or high blood glucose levels. 

Some other conditions can increase the risk of myeloma by a small amount. The conditions include some in which the immune system starts to damage the body (autoimmune conditions), infections, and inflammatory conditions. 

Autoimmune conditions

• General muscle inflammation (polymyositis)
• Inflammation of the muscles and skin (dermatomyositis)
• Abnormal growth of connective tissue (systemic sclerosis)
• Autoimmune haemolytic anaemia
• Pernicious anaemia
• A type of arthritis that mainly affects the lower back called ankylosing spondylitis

Infections

• Chest infection (pneumonia)
• Long term liver infection (hepatitis C)
• Infection of the membranes around the brain and spinal cord (meningitis)
• Blood poisoning (septicaemia)
• Chicken pox or shingles (herpes zoster virus)
• Polio

Inflammatory conditions

• Kidney inflammation (glomerulonephritis or nephrotic syndrome)
• Osteoarthritis - swelling of joints, most often the hands, knees, hips, feet or spine.

Studies show that people with a parent, brother, sister, or child with myeloma or monoclonal gammopathy of unknown significance (MGUS) are twice as likely to develop myeloma compared to the general population.

People who have had thyroid cancer have been shown to have an increased risk of myeloma. It is not known whether the increased risk is due to the treatment for the thyroid cancer or due to a gene change that can stimulate myeloma and thyroid cancer. 

People who have had a type of eye cancer called ocular melanoma have a risk of myeloma that is twice that of the general population.

There is some evidence that people who are overweight or obese may have up to double the risk of myeloma compared to people with a healthy bodyweight. 

One large European study showed that taller women have a higher risk of multiple myeloma compared to shorter women.

Four studies have shown a reduced risk of myeloma in people who eat a lot of fish. A smaller number of studies have shown that eating cruciferous vegetables (such as broccoli, cauliflower and cabbage) and green vegetables may reduce the risk of myeloma.

Some research has suggested that some jobs may be associated with an increased risk of developing multiple myeloma although these links haven't been proved. You may have an increased risk if you work in

• The petrol or oil industry because of exposure to benzene
• Farming because of exposure to some pesticides
• Woodworking or the leather industry
• Painting and decorating
• Hairdressing, because of exposure to hair dyes
• Rubber manufacturing
• Firefighting

We must stress that there is not enough evidence to prove that any of these occupations carry an increased risk of myeloma. Myeloma is a relatively uncommon condition. So even if any of these occupations are associated with increased risk, there must be other factors that dictate why one person develops myeloma and another doesn't.

If you have been exposed to high levels of radiation in the past, you may have an increased risk of developing myeloma.

One study has shown that people who take paracetamol (acetaminophen) regularly may have an increased risk of myeloma. Regular use of paracetamol means taking it at least once a week for at least 6 months.

Two studies have shown that women who take hormone replacement therapy (HRT) have a lower risk of myeloma.

Drugs used to lower cholesterol levels (statins) have been linked to a reduced risk of myeloma in one study. The same study showed an increase in risk in people who have taken insulin, gout medicines or a steroid called prednisone. More studies are needed to confirm these findings though.