Researchers have identified several factors that may influence the risk of obesity in childhood cancer survivors.
Previous research showed that obesity rates are elevated in childhood cancer survivors who were exposed to cranial radiation.
But the new study has shown that other types of treatment, a patient’s age, and certain genetic variants are associated with obesity in this population.
Carmen Wilson, PhD, of St. Jude Children’s Research Hospital in Memphis, Tennessee, and her colleagues reported these findings in Cancer.
The researchers evaluated 1,996 childhood cancer survivors treated at St. Jude. The patients’ median age at diagnosis was 7.2 years (range, 0.1-24.8), and their median age at follow-up was 32.4 years (range, 18.9-63.8).
At the time of evaluation, 645 patients (32.3%) were of normal weight, 71 (3.6%) were underweight, 556 (27.9%) were overweight, and 723 (36.2%) were obese.
The prevalence of obesity was highest in male leukemia survivors (42.5%) and females who survived neuroblastoma (43.6%), followed closely by those who survived leukemia (43.1%).
Multivariable analyses showed that 3 factors were independently associated with an increased risk of obesity: older age at the time of evaluation (≥30 years vs <30 years; P<0.001), undergoing cranial radiation (P<0.001), and receiving glucocorticoids (P=0.004).
On the other hand, receiving chest, abdominal, or pelvic radiation was associated with a decreased risk of obesity (P<0.001).
The researchers also identified 166 single nucleotide polymorphisms that were associated with obesity among cancer survivors who had received cranial radiation. The strongest association was in variants of genes involved in neuron growth, repair, and connectivity.
Among survivors who did not receive cranial radiation, only 1 single nucleotide polymorphism—rs12073359, located on chromosome 1—was associated with an increased risk of obesity.
Dr Wilson said these findings might help us identify the childhood cancer survivors who are most likely to become obese. The results may also provide a foundation for future research efforts aimed at characterizing molecular pathways involved in the link between childhood cancer treatment and obesity.
