CHLA Logo Obesity has been linked with a rising incidence of several cancers including leukemia but it has been unknown whether the increase in incidence was a direct effect of obesity or associated with genetic, lifestyle, health, or socio-economic factors. The research conducted by the Saban Research Institute of Childrens Hospital Los Angeles claims to be the first to reveal that obesity may directly enhance the progression of acute lymphoblastic leukemia.

Scientists used a high-fat diet to enhance obesity in two mouse models of ALL. The mice included in the analysis were randomized to a high-fat or a control diet. Investigators identified that obesity augmented the risk of ALL in both models specifically in older mice.

Steven D. Mittelman, MD, PhD, a pediatric endocrinologist who led the analysis elucidated, “Given the high prevalence of obesity in our society, we felt it was critical to determine if obesity actually caused the increased incidence of leukemia and not some other associated exposure.”

Researchers revealed that the observation was steady with the type of cumulative effect seen with other exposure-related cancers like lung cancer related to smoking and breast cancer ensuing from amplified estrogen exposure. They highlighted the difference among older animals and further agreed with the other obesity-related effects from cumulative exposure like heart disease, diabetes, and arthritis.

“Our findings are consistent with epidemiological data that show a higher incidence of leukemia in obese adults and suggests that these observations are actually due to obesity, and not some associated genetic, socio-economic, or lifestyle factor,” remarked Dr. Mittelman, who is also an Assistant Professor of Pediatrics and Physiology & Biophysics at the Keck School of Medicine of the University of Southern California.

These findings highlight that some hormone or factor in overweight individuals mainly produced by fat tissue may signal leukemia cells to develop and fragment. Researchers share that leukemia is apparently the most common type of childhood cancer and evaluating how obesity may boost its incidence could have significant public health implications.

These findings will be published in Cancer Prevention Research, on October 5, 2010.