A risk factor is anything that changes a person's chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancer of the lung and many other cancers. But risk factors don't tell us everything. People who have no risk factors can still get the disease. Also, having a risk factor, or even several, does not mean that a person will get the disease.

Scientists have found few risk factors that may affect someone's chance of getting multiple myeloma.

Age

The risk of multiple myeloma goes up with age. Less than 1% of cases are diagnosed in people younger than 35. Most people diagnosed with this cancer are over 65 years old.

Gender

Men are slightly more likely to develop multiple myeloma than women.

Race

Multiple myeloma is almost twice as common among black Americans as white Americans. The reason is not known.

Radiation

Exposure to radiation may increase the risk of multiple myeloma. At most, this accounts for a very small number of cases.

Family history

Multiple myeloma does seem to run in some families. Someone who has a sibling or parent with myeloma is 4 times more likely to get it than would be expected. Still, most patients have no affected relatives, so this accounts for only a small number of cases.

Workplace exposures

Some studies have suggested that workers in certain petroleum-related industries may be at a higher risk.

Obesity

A study by the American Cancer Society has found that being overweight or obese increases a person’s risk of developing myeloma.

Other plasma cell diseases

Many people with MGUS or solitary plasmacytoma will eventually develop multiple myeloma.

Last Medical Review: 02/13/2009
Last Revised: 05/12/2009