Obesity among childhood cancer survivor study participants: New targets for intervention

Background: Obesity is among the multiple late effects of pediatric cancer therapy, and it compounds survivors' existing risk of cardiomyopathy, osteoporosis, diabetes, and second malignancy. Methods: A broad-based health behavior model and structural equation modeling were used to analyze and interpret data derived from baseline and follow-up surveys of the Childhood Cancer Survivor Study. We evaluated the influence of demographic, intrapersonal, lifestyle, and treatment factors on obesity (body mass index [BMI] ≥ 30 kg/m2) among 4950 survivors (mean current age, 32.0 y; mean age at diagnosis, 8.35 y; mean years since diagnosis, 23.7). Results: A well-fitting model (CFI=0.996, TLI=0.997, RMSEA=0.027, probability RMSEA ≤0.05 = 1.000) identified 8 moderators of obesity (sex, current age, education, total household income, diagnosis, cranial radiation therapy, growth hormone deficiency, and exercise frequency at baseline) (P ≤ 0.041). Direct predictors of obesity included: a diagnosis of leukemia or lymphoma (P ≤ 0.001), paroxetine (anti-depressant) use (P = 0.003), reduced physical function (P ≤ 0.001), less depression (P = 0.011), less education (P = 0.005), less cancer-related anxiety (P = 0.003), less total household income (P = 0.028), and lower baseline exercise frequency (P = 0.008) compared to those survivors who were not obese. Cancer-related pain influenced obesity indirectly through physical function (P ≤ 0.001) and anxiety (P = 0.012); inactivity influenced obesity indirectly through cancer pain (P = 0.004). Paroxetine use was a strong correlate of depression (P ≤0.001), pain (P ≤0.001), and anxiety (P ≤ 0.001). Conclusions: While anti-depressant use may benefit survivors by modifying anxiety and depression, the strong association of paroxetine with obesity raises concern about the risk of obesity-related chronic illnesses. Longitudinal studies of the temporal order of psychological symptoms, the efficacy and dose responses of a variety of anti-depressants, and the impact of both on obesity in this population are warranted. Physical therapy and assisting the survivor to adopt a more active lifestyle may help to improve physical function, and reduce pain and psychological sequelae. Increased physical activity, improved physical function and affect may in turn help to reduce obesity and the need for anti-depressants.