There is no single cause of this type of cancer, and oftentimes no clear answer as to why one person develops it and another does not.
If you or someone you love has been diagnosed with multiple myeloma, one of the first questions that often comes up is: What causes multiple myeloma?
However, learning about the risk factors and what may cause multiple myeloma can assist in making sense of the diagnosis and making informed choices.
What is multiple myeloma?
Multiple myeloma is a cancer that forms in plasma cells, which are white blood cells that help fight infections.
When these cells become abnormal, they grow uncontrollably and crowd out healthy blood cells. Over time, this disrupts the immune system (Blood Cancer United 2026).
Early symptoms of multiple myeloma
The early symptoms of multiple myeloma can show up in different ways. Some of the most commonly reported include (Blood Cancer United 2025):
Bone pain, particularly in the back, hips, or chest
Fatigue that doesn’t improve with rest
Frequent infections, due to a weakened immune system
Kidney problems, which may show up as changes in urination or increased thirst
Weakness or numbness in the legs
Many of these symptoms overlap with other common, less serious health issues. Experiencing them doesn’t mean you have multiple myeloma, but they are worth talking about with your healthcare provider.
If you’ve noticed any of these symptoms and they persist or worsen, reaching out to your doctor is always the right move.
Genetic factors
Most cases of multiple myeloma begin with acquired genetic mutations in plasma cells (Blood Cancer United 2025).
These mutations disrupt how your cells:
Grow and divide
Repair damage
Undergo normal cell death
While these changes are complex, they are common in many cancers and are a focus of ongoing research and treatment advances.
Environmental and lifestyle risk factors
Learning about risk factors can feel like a lot to take in, especially if some of them feel familiar. Remember that risk factors do not mean a person is guaranteed to have specific health outcomes.
Age
As we get older, the likelihood of genetic mutations in our cells increases. If you’re 50 or older, this may slightly raise the risk of developing multiple myeloma (Blood Cancer United 2025).
Sex
Males are diagnosed with multiple myeloma more often than females. While researchers continue to study this increase, this risk is just one potential factor (Blood Cancer United 2025).
Race and ethnicity
According to the NCCN, multiple myeloma is twice as common and twice as likely to lead to death in African Americans compared to white people living with myeloma (National Comprehensive Cancer Network 2026).
However, research shows that differences in outcomes are often driven by access to care. A real-world study by ASH found that when African American people with myeloma have similar access to care as white people, their survival outcomes are comparable (American Society of Hematology 2022).
Nutrition
Focusing on overall health and regular medical care (ex: healthy diet and weight) can help reduce risk and support early detection (Blood Cancer United 2025).
You can learn more about diet in our recent webinar: Dietary, Microbiome and Metabolism Evidence in Blood Cancers (Focus on Myeloma).
Chemical and radiation exposure
Exposure to certain chemicals or radiation may play a role in the development of multiple myeloma. These include:
Pesticides
Fertilizers
Agent Orange
Metals (cadmium, antimony, lead)
These substances can affect how cells repair damage over time, which may increase cancer risk. If you work with or have lived in environments with these exposures, let your provider know so they can monitor your health appropriately.
The good news is that, even with these risk factors, many people never develop the disease and having them does not mean a diagnosis is inevitable. These are considered risk factors, not direct causes (Blood Cancer United 2025).
A final word
While uncertainty can be difficult, ongoing research continues to improve our understanding and treatment of this disease. It’s important to remember:
Multiple myeloma develops over time
Most causes are not preventable or inherited
Risk factors increase the likelihood but do not guarantee disease
You don’t have to navigate these questions alone—and we’re here to help you take the next step, whatever that looks like for you.
What matters most is working closely with your medical team, learning as much as you can about your disease, and getting the right kind of help.
And if you’d like to learn more about multiple myeloma, Blood Cancer United has resources for you.
