The St. Jude Lifetime Cohort study found obesity in a higher percentage of adult survivors of childhood cancer than previous studies.
Thirty-six percent of the research project’s 1,996 participants were obese, which the study defined as having a body mass index (BMI) of greater than or equal to 30 kg/m2. All of the study’s participants previously had received treatment for cancer at St. Jude Children’s Research Hospital, Memphis, Tenn., and had been cancer survivors for at least 10 years.
The prevalence of obesity was even higher in the subset of the sample that had been treated with cranial radiation (CRT). Forty-five percent of such survivors were obese, compared to 29.4% of the study’s participants, who had not been exposed to CRT. Another finding specific to the cancer survivors that had received CRT were associations between obesity, and variations in the regions in and around the genes FAM155A, GLRA3, CDH18, and SOX11.
“Because both CDH18 and SOX11 appear to influence neuronal growth, repair, and connectivity, these genes may be important regulators of neuronal response to radiation-induced damage among CCS,” according to Carmen L. Wilson, Ph.D., and her colleagues. They added that single nucleotide polymorphisms in such genes could alter obesity risk but said more research needs to be conducted to confirm this.
Among the study’s other findings were that older age at evaluation, previous treatment with CRT, and glucocorticoid exposures were independently associated with obesity. Chest, abdominal, or pelvic, radiation exposure, in contrast, were negatively correlated with having a BMI at or above 30 kg/m2.
The study has confirmed that “the high prevalence of obesity among [survivors of childhood cancer] persists decades after cancer treatment and appears to be influenced by therapies received during childhood and obesity status at diagnosis,” according to the researchers.
Read the full study in Cancer (doi: 10.10002/cncr.29153).