Multiple myeloma is the second most common blood cancer in the United States, striking more than 20,000 individuals each year. The incidence is higher in men and increases with advanced age. Although the causes are unclear, certain risk factors increase the likelihood of developing this malignancy.
Age
The Mayo Clinic states that advanced age increases your risk for multiple myeloma, with most people diagnosed in their mid-60s. According to the National Cancer Institute, the majority of patients are between 50 and 70 years of age. Very few people under the age of 40 develop this cancer.
Gender
Men are more likely to develop multiple myeloma than women, according to the American Cancer Society. In 2009, there were 11,680 new cases in men and 8,900 in women.
Ethnicity
In the United States, the risk for multiple myeloma is two times higher in African-Americans than Caucasians. Other ethnic groups also have higher myeloma rates than Caucasians including Hawaiians, Hispanics and American Indians. The cause of the higher risk in these groups remains unknown.
Genetic Abnormalities
Certain genetic abnormalities are found in virtually all people with multiple myeloma, according to the Mayo Clinic. The most common problem is that chromosome 13 is defective or missing. According to the American Cancer Society, the myeloma cells in about half of patients have translocated chromosomes, which means that part of one chromosome has switched with part of another chromosome. Having a similar genetic profile may explain why a person's risk for multiple myeloma is higher if a family member had the disease.
History of Monoclonal Gammopathy of Undetermined Significance (MGUS)
The risk for multiple myeloma is higher in people with MGUS, a disease without symptoms that does not damage the body. Like multiple myeloma, MGUS is characterized by an increase in M-protein levels and abnormal plasma cells in bone marrow. Each year, 1 percent of people with MGUS develop multiple myeloma.
Exposure to Ionizing Radiation
Exposure to ionizing radiation is firmly established as a cause of multiple myeloma, according to the National Cancer Institute. People exposed to high levels of radiation, such as atomic bomb survivors in Japan, are five times more likely to develop this disease. The prevalence is also higher in people exposed to lower amounts of radiation, including radiologists and nuclear plant workers. There is no evidence, however, that exposure to medical x-rays increases the risk.
Exposure to Certain Chemicals
Multiple myeloma is more common in people who have been exposed to certain chemicals, such as farmers and petroleum workers.
