Insulin levels in the mother's body during fetal development or possible changes to the mother's DNA expression passed to her offspring may increase the risk for developing leukemia.
A new studying using Pennsylvania birth records has found a correlation between children born to pre-pregnancy body-mass index (BMI) and the likelihood of developing childhood cancer, even after correcting for known risk factors, such as newborn size and maternal age.
The study, published in the American Journal of Epidemiology, included the data gathered from approximately 2 million birth records and 3000 cancer registry records filled in the state of Pennsylvania between 2003 and 2016. Investigators found that children born to severely obese mothers, or mothers with a BMI above 40, had a 57% higher risk of developing leukemia before age 5. Weight and height also were individually associated with increased leukemia risk.
"Right now, we don't know of many avoidable risk factors for childhood cancer," said lead author Shaina Stacy, PhD, postdoctoral scholar in the Pitt Public Health Department of Epidemiology and UPMC Hillman Cancer Center. "My hope is that this study can be, in a way, empowering and also motivating for weight loss."
The investigators’ analysis showed that obese women were not necessarily giving birth to larger babies or that these women tended to be older, which are known risks of childhood cancer. Rather, it was the mother’s size that was independently contributing to her child’s risk.
Insulin levels in the mother's body during fetal development or possible changes to the mother's DNA expression that are passed to her offspring may be possible causes to this correlation.
The authors noted that not all levels of obesity carry the same risk, yet women in the study who had a higher BMI had children with a higher risk of cancer. Even a small amount of weight loss can translate to a real reduction in risk.
"We are dealing with an obesity epidemic in this country," said senior author Jian-Min Yuan, MD, PhD, professor of epidemiology at Pitt Public Health and co-leader of the cancer epidemiology and prevention program at UPMC Hillman Cancer Center. "From a prevention point-of-view, maintaining a healthy weight is not only good for the mother, but also for the children, too."