Obesity, myeloma, and younger age of onset
February 07, 2019
Obesity, myeloma, and younger age of onsetWRITTEN BY: Brian GM Durie MD
The average age of first diagnosis of myeloma is 67. However, as reported in The New York Times, a new study shows that those born in 1985 (or later) had a 59 percent higher risk of developing myeloma versus individuals born in 1950 (or earlier). Adults in this study aged 25 to 49 had an increased risk of developing myeloma, and it was linked to the increased occurrence of obesity in this younger population. This is something quite new and unexpected. It is definitely a wake-up call about both the magnitude of the obesity epidemic in the U.S. and the potential for serious consequences.
What is obesity and how has it been linked to MGUS (monoclonal gammopathy of undetermined significance) and MM (multiple myeloma)?
Obesity is defined by BMI (Body Mass Index), which is weight in kilograms divided by height (expressed in meters and squared). A value of 18.5 to 24.9 is considered normal. A level of 25 to 29.9 is overweight. A BMI over 30 is obesity. A very helpful study of 7,878 patients with MGUS by S.H. Chang and associates from the Washington University School of Medicine showed that the presence of obesity, as well as black race, were risk factors for transformation of MGUS into active myeloma. They also showed a trend toward a younger age for such patients. This is in line with the results from a study from Iceland, home of the iStopMM project, which showed a lesser risk of progression from MGUS to MM among patients sticking with a traditional high-fish intake, “healthy” diet.
Evolving causes of myeloma
These findings highlight important trends related to age. Between 1980 and 2014, overweight or obesity prevalence increased by more than 100 percent among American children and adolescents, reports the Centers for Disease Control and Prevention. Weight gain comes with risk for the associated medical consequences.
But obesity is only one factor. The pattern of environmental toxic exposures is also changing. For example, exposure to high levels of benzene are less likely due to laws limiting benzene concentrations in gasoline and manufacturing. However, other toxic exposures are more likely, such as exposures to chemicals in processed foods and drinks, which I have blogged about here and here. The nature of the myeloma itself is changing, and we should expect differences in the impact of treatments and outcomes over time.
Implications of earlier age of onset
Myeloma in a patient between ages 25 and 49 is a new diagnostic challenge. There must be education to be aware of this demographic shift and to search more scrupulously for possible myeloma in younger patients. Also, we must look more closely at the patterns of disease and outcomes with treatment.
Finally, a place for prevention
The very good news is that there is broad evidence that correction of obesity reduces the risk of developing cancer. However, it remains to be established if weight loss can reduce the risk of progression of MGUS to active myeloma. Research in this area is needed. There are, fortunately, many helpful practical guides to weight loss, but we will need a randomized clinical trial to demonstrate the value. This now becomes a top priority.
The bottom line: Myeloma is now developing at a younger age, linked to obesity. Perhaps weight loss will be the first true prevention strategy for the reduction of progression of MGUS to active myeloma! We will keep you posted.