Although a high body mass index (BMI) has been linked to an increased risk for hematological malignancies, Swedish researchers found that excess belly fat, not BMI, is a more appropriate predictor of risk for these types of cancers.1
The population-based study, published in PLoS One, included body composition measurements of 27,557 individuals who were part of the Malmö Diet and Cancer study in Sweden between 1991 and 1996. Various body composition measurements were calculated for all individuals, including values for hip and waist, for BMI, waist circumference (WC), waist-hip ratio (WHR), waist-to-height ratio (WHtR), waist-to-hip-to-height ratio (WHHR), the A Body Shape Index (ABSI), and body fat percent.
Patients were followed for a median of 20 years, during which time 564 subjects developed a hematologic malignancy.
The reason the researchers were interested in the influence of measures of body composition outside of BMI and their influence on the development of blood cancers was because, as they wrote, BMI often relies on self-reported weight and height values, and therefore, may be less accurate than alternative markers for obesity. Plus, BMI often misclassifies those who have a high muscle mass as overweight.
Extra belly fat was found to be a more precise indicator of the risk of blood cancer. Although individuals with a BMI of more than 30 kg/m2were found to have a statistically significant risk of MM (P= .01), in individuals with a BMI between 25 kg/m2and 30 kg/m2, standardized WHR was significantly associated with MM (P= .047).
The strongest estimators of risk for multiple myeloma (MM) were high WC, high WHR, and high WHtR; all of these measurements reflect higher adiposity around the waist. The investigators wrote that these values better mirror the specific type of fat that individuals have, and may be better values for cancer risk calculations. This type of abdominal obesity has been shown to better predict cardiovascular and liver diseases compared with BMI, so they reasoned it may also be more accurate for risk assessment in blood cancer.
Though the authors did not provide reasoning for why this type of excess fat may increase the risk of disease, they wrote that prior studies have suggested that increases in the levels of glucose, adiponectin, or leptin (as a result of more belly fat) have been associated with an increased risk of various blood cancers. They did not calculate how changes to this type of fat over time could influence the risk of developing a blood cancer, however, which was cited as a study limitation.
- Hagström H, Andreasson A, Carlsson AC, Jerkeman M. Body composition measurements and risk of hematological malignancies: a population-based cohort study during 20 years of follow-up.PLoS One. 2018;13(8);e0202651. doi: 10.1371/journal.pone.0202651