There are several risk factors linked to multiple myeloma, including age, genetics, obesity, radiation exposure, and other conditions.

Multiple myeloma is cancer of the plasma cells. These plasma cells are a type of white blood cell that makes antibodies to help fight infections.

If a person has multiple myeloma, they produce too many plasma cells, and can develop tumors. These cells can crowd out other normal cells in the bone marrow that create red blood cells and other white blood cells.

Multiple myeloma may cause no symptoms. However, more advanced types may cause bone pain, fever, bones that break easily, bleeding, and bruising.

In this article, we provide an overview of the risk factors for multiple myeloma. We also look at whether people can prevent this disease and early signs of the cancer.

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The risk of developing multiple myeloma increases as people get older. Most cases occur in people who are at least 65 years old.

The average age of people diagnosed with multiple myeloma is between 66 and 70 years old. About 37% of people with multiple myeloma are younger than 65 at the time of diagnosis. It is possible for the cancer to develop in young people, however, less than 1% of cases occur in people younger than 35 years old.

Medical professionals have identified certain mutations of multiple myeloma as genetic risk factors. However, they do not consider it to be a hereditary disease.

People with siblings or parents with multiple myeloma may be more likely to develop the cancer than those who have no family history of it. However, most people with the cancer have no relatives who have multiple myeloma.

Some families may have an increased risk of developing the cancer, but experts do not know what the pattern of inheritance is.

If a person has obesity, they may be at increased risk of developing several different types of cancer, including multiple myeloma. Research suggests that if a person has an increased body mass index (BMI), they are at greater risk of developing the disease.

Experts believe having obesity increases the risks of certain types of cancers in various ways, especially hormone related cancers in women and those affecting digestive organs. These include:

  • causing the blood vessels and cells to grow
  • increasing inflammation in the body
  • changing levels of certain hormones which can contribute to the growth of cancer cells

Research has also found that obesity could be linked to the transformation of a benign condition, called monoclonal gammopathy of undetermined significance (MGUS), into multiple myeloma.

In rare cases, a person may be at higher risk of developing multiple myeloma if they have been exposed to X-rays or other kinds of ionizing radiation.

The Center for Environmental Health Studies reported that people who worked at nuclear facilities and who were regularly exposed to ionizing radiation experienced higher rates of death due to multiple myeloma than the general population.

One study found that workers at a uranium enrichment site who breathed in or swallowed radioactive particles had a 4% higher chance of dying of multiple myeloma than workers exposed in other ways. It found no increased chance of multiple myeloma in workers who were only exposed to radiation outside the body.

If a person has another plasma cell condition, they may be at higher risk of developing multiple myeloma. These include:

Monoclonal gammopathy of undetermined significance (MGUS)

MGUS is a benign condition in which a person has abnormal plasma cells in their bone marrow, which produce an abnormal protein.

There are often no symptoms of MGUS. However, the condition can sometimes transform into multiple myeloma. It progresses into the cancer at a level of 1% per year.

Almost all cases of multiple myeloma progress from the MGUS pre-malignant stage. MGUS is present in about 3% of people over 50 years old.

Solitary plasmacytoma

Solitary plasmacytoma is a rare condition that makes up around 2 to 5% of all plasma cell disorders. This is a condition in which abnormal plasma cells concentrate in a single tumor, called a plasmacytoma.

Plasmacytoma often develops into multiple myeloma, with 65 to 84% of cases progressing into the cancer within 10 years.

Men have a slightly higher risk than women of developing multiple myeloma. Experts do not know why.

The American Cancer Society estimates the amount of new cases of multiple myeloma in the United States for 2021 to be:

  • around 34,920 new cases: 19,320 in men and 15,600 in women
  • about 12,410 deaths from multiple myeloma: 6,840 in men and 5,570 in women

Multiple myeloma is twice as common in Black people than in other races in the U.S. Research has found that the cancer is also significantly more common in Black people globally than in other races. Black people with multiple myeloma are also twice as likely to die from the disease compared to white patients.

There may be several factors which contribute to the prevalence of the disease and higher rate of death in Black people. These include:

Health inequity

The higher death rate of Black people with multiple myeloma appears to be due to inferior treatment from the healthcare system, rather than because of underlying illnesses or genetic differences.

There are many care disparities between Black and white patients. For example, Black patients are 50% less likely to undergo stem cell transplantation, even though the treatment provides the same level of survival benefit for Black and white patients.

Black patients also are less likely than white patients to receive treatment with the drugs Revlimid and Velcade, even though these drugs have become the standard of care for multiple myeloma patients.

Studies have shown that Black patients can achieve the same results as other myeloma patients when they receive timely, appropriate care.

Socioeconomic factors

Studies state that socioeconomic status is a major risk factor for many types of cancer. Marginalized communities are more likely to experience poverty than their white counterparts. Some 39% of African American children and adolescents are living in poverty, which is more than double the 14% rate of poverty among white, Asian, and non-Latino children and adolescents.

Socioeconomic factors may increase the risk of multiple myeloma due to environmental and lifestyle factors, and access to healthcare services.

Biological factors

Black people are more likely to develop MGUS, which can lead to multiple myeloma. Black myeloma patients also experience more risk factors of the disease, such as anemia, and increased levels of lactate dehydrogenase, which can increase the progress of disease.

Few cases of multiple myeloma are linked to avoidable risk factors. There is no known way for a person to prevent the disease from developing if they have MGUS or solitary plasmacytomas.

It is difficult for doctors to diagnose multiple myeloma early, as it often causes no symptoms until it is at an advanced stage. A doctor may be able to detect it early if blood tests show abnormally high protein levels.

Symptoms may include:

  • bone pain, weakness, or bones breaking easily
  • low numbers of red cells (anemia), white blood cells (leukopenia), and blood platelet counts (thrombocytopenia)
  • high levels of calcium in the blood
  • nervous system symptoms such as severe, sudden back pain, and muscle weakness
  • hyperviscosity, which is a thickening of the blood
  • kidney problems
  • infections, such as pneumonia

Multiple myeloma is a cancer that affects bone marrow cells called plasma cells. It causes these cells to grow too much, crowding out healthy blood cells and damaging bone tissue.

There are several risk factors for multiple myeloma, including age, sex, obesity, radiation exposure, and race.

Having other plasma cell conditions can also increase the risk of multiple myeloma, especially MGUS. Almost all multiple myeloma patients have previously had MGUS.

Multiple myeloma cannot be prevented. It also is difficult to diagnose early, although a blood test may reveal high protein levels which can help doctors diagnose the condition.

Multiple myeloma may present no symptoms, but some symptoms may occur including bone pain or weakness, nervous system issues, and infections.