Purpose: To determine whether adult survivors (>or= 18 years of age) of childhood acute lymphoblastic leukemia (ALL) are at increased risk for obesity and to assess patient and treatment variables that influence risk.
Patients and methods: A retrospective cohort of participants of the Childhood Cancer Survivor Study was used to compare 1,765 adult survivors of childhood ALL to 2,565 adult siblings of childhood cancer survivors. Body-mass index (BMI; kilograms per square meter), calculated from self-reported heights and weights, was used to determine the prevalence of being overweight (BMI, 25-29.9) or obese (BMI >or= 30.0). Polytomous logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for being overweight or obese among ALL survivors relative to the sibling control group.
Results: The age- and race-adjusted OR for being obese in survivors treated with cranial radiation doses >or= 20 Gy in comparison with siblings was 2.59 for females (95% CI, 1.88 to 3.55; P <.001) and 1.86 for males (95% CI, 1.33 to 2.57; P <.001). The OR for obesity was greatest among females diagnosed at 0 to 4 years of age and treated with radiation doses >or= 20 Gy (OR, 3.81; 95% CI, 2.34 to 5.99; P <.001). Obesity was not associated with treatment consisting of chemotherapy only or with cranial radiation doses of 10 to 19 Gy.
Conclusion: Cranial radiotherapy >or= 20 Gy is associated with an increased prevalence of obesity, especially in females treated at a young age. It is imperative that healthcare professionals recognize this risk and develop strategies to enhance weight control and encourage longitudinal follow-up.