When I was diagnosed with multiple myeloma, it was preceded over several years by a 15 pound weight loss. I thought my body was ready to get back to my college weight after 6 pregnancies, but no such luck. The weight loss was caused by my growing multiple myeloma. Recent research from Taiwan researchers now shows that low body weight at diagnosis is associated with poorer overall survival. 

Unexplained weight loss can be a common sign of multiple myeloma along with undernutrition and muscles wasting (also called cachexia.). In the study, a total of 378 newly diagnosed myeloma patients were enrolled. Thirty patients (7.9%) were underweight at diagnosis. Median overall survival was 1.3 years for patients with low Body Mass Index (BMI under 18.5 kg/m²), and 5 years for patients with normal or higher BMI. Patients with low BMI, high LDH, low albumin and a light chain ratio over 100 were independent risk factors for worse overall survival. 

The data can be confusing as we have also read data showing that patients who are obese can be more prone to myeloma progression from precursor MGUS and smoldering myeloma stages.

To dig deeper in to this obesity finding, a Dana Farber Cancer Institute study assessed 582 myeloma patients and found that patients who had large ups and downs in weight (for example, those with weight gain and one or more cycles of intentional weight loss of 20 pounds or more) had increased myeloma risk compared to patients who maintained their weight. They also found that myeloma increased with increasing hip circumference but myeloma growth was not associated with other body fat distribution measures. 

In summary, unintentional weight loss can be caused by the myeloma itself. When possible, it's best to maintain a healthy and consistent weight through life to provide the strongest benefit for myeloma prevention and better overall outcomes.