Myeloid Leukemia Risk Linked to Obesity

Association not seen with other types of leukemia, study says

TUESDAY, Aug. 2, 2005 (HealthDay News) -- The risk of developing myeloid leukemia appears to significantly rise as body weight and waist size increase, Australian researchers report.

While the risk of developing myeloid leukemia increased with body mass index, fat-free mass and waist circumference, the risk of other blood cancers -- such as multiple myeloma, lymphocytic leukemia, hairy cell leukemia, Hodgkin lymphoma, and non-Hodgkin lymphoma -- did not, the investigators found.

The report appears in the Aug. 3 issue of the Journal of the National Cancer Institute.

In their study, Graham G. Giles, from the Cancer Council Victoria in Melbourne, and his team collected data on 40,909 people aged 27 to 75. They followed this group for slightly more than eight years.

During that time, they measured waist and hip size, height and weight, calculated the waist-to-hip ratio and the body mass index, and measured the fat mass and fat-free mass of each participant. They also collected data about cancers among these people.

The research team found that people who were overweight or obese had five times the risk of developing myeloid leukemia compared with those whose weight was normal. In addition, people who had extra weight around the middle had a higher risk of developing myeloid leukemia, according to the report.

"We found that overall adiposity (including central) and non-adipose mass (or fat-free mass) were both associated with myeloid leukemia," the authors wrote. "However, they were not associated with any other lymphohematopoietic malignancies."

One expert believes that added weight is a factor in both the risk for myeloid leukemia and its treatment.

"It is clear from epidemiological studies that there is an increased risk of myeloid leukemia in fat people," said Dr. Anna M. Butturini, an associate professor of clinical pediatrics at the Keck School of Medicine at the University of Southern California.

"It is possible that there is something in fat tissue that makes the risk of myeloid leukemia more likely," she added.

In adults and children who are overweight and have myeloid leukemia, the risk of relapse is greater, Butturini noted. "This is probably due to the fact that the [chemotherapy] treatment we are doing in fat people doesn't work as well as in non-fat people," she said.

"We really don't know how to dose chemotherapy in fat people," Butturini said. "It could just be the fact that we are not good enough, or it is possible that leukemia cells in fat people respond differently than in non-fat people."

Another expert, Eugenia Calle, director of analytic epidemiology at the American Cancer Society, thinks the new findings highlight an emerging trend in cancer research -- that is, finding a link between body weight and the risk for blood cancers.

"This study adds to a growing literature that has been looking at the influence of body size on blood cancers," Calle said. "But we don't have strong conclusions yet."

More information

The American Cancer Society can tell you more about leukemia.

SOURCES: Anna M. Butturini, M.D., associate professor, clinical pediatrics, Keck School of Medicine, University of Southern California, Los Angeles; Eugenia Calle, Ph.D., director, analytic epidemiology, American Cancer Society, Atlanta; Aug. 3, 2005, Journal of the National Cancer Institute
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