Multiple myeloma is a rare cancer, affecting about 20,000 Americans each year. Although the exact causes remain unclear, several risk factors have been identified. Established risk factors include older age and male gender, black race and family disease history. Epidemiologic research suggests other risk factors, including obesity and exposure to pesticides.
Age and Gender
It's well established that increasing age and male gender are risk factors for multiple myeloma. According to the National Cancer Institute, most people with this cancer are diagnosed after age 65. On the other hand, very few people younger than 40 develop this disease.
Black Race
According to the International Journal of Cancer, the risk for multiple myeloma is two to three times higher in African-Americans. Hawaiians and American Indians also have an elevated risk; Asian-Americans have a low risk. The reasons for different disease rates among ethnic groups remain unknown.
Positive Family History
The Mayo Clinic reports that having a relative with multiple myeloma or another blood cancer increases the risk for developing this disease. It may be that relatives have a similar genetic weakness, such as defect in chromosome 13, which is found in virtually all patients with this multiple myeloma. Another problem found in half of patients is translocated chromosomes, which means that chromosomes have exchanged parts.
Ionizing Radiation
Exposure to high levels of ionizing radiation causes multiple myeloma, according to the National Cancer Institute. This is evidenced by Japanese atomic bomb survivors, whose risk for this cancer is five times higher. The incidence is higher in radiologists and nuclear plants workers as well. There is no link, however, between medical X-rays and multiple myeloma.
Monoclonal Gammopathy of Undetermined Significanc (MGUS)
MGUS, a benign condition characterized by abnormal plasma cells and the presence of the M protein, is strongly associated with multiple myeloma. According to the Mayo Clinic, 25 years after diagnosis, 39 percent of people with MGUS have developed multiple myeloma. The cause of MGUS remains unknown, reports the International Journal of Cancer, although, like multiple myeloma, the prevalence is higher in males and African-Americans.
Obesity
Obesity is consistently associated with a higher risk for multiple myeloma, reports the International Journal of Cancer. The elevated risk in obese people is shown in large epidemologic studies conducted all over the world.
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Pesticides
Exposure to pesticides may cause multiple myeloma. A study of nearly three million people in Sweden showed that workers exposed to pesticides, even if occasionally, had a higher risk for this cancer. The risk was particularly strong if they were exposed to intense levels. However, researchers are unsure about this finding, as other studies haven't shown a link between exposure to pesticides and multiple myeloma.
References
- National Cancer Institute. What You Need to Know About Multiple Myeloma
- Alexander D. Multiple Myeloma: A Review of the Epidemiologic Literature. Int J Cancer. 2007
- Mayo Clinic.com. Multiple Myeloma. http://mayoclinic.com/health/multiple-myeloma/DS00415
- Occupation, Exposure to Chemicals, Sensitizing Agents, and Risk of Multiple Myeloma in Sweden. Cancer Epidemiol Biomarkers Prev. 2008.
