Diabetes mellitus in long-term survivors of childhood cancer. Increased risk associated with radiation therapy: a report for the childhood cancer survivor study.

BACKGROUND: Childhood cancer survivors are at increased risk of morbidity and mortality. To further characterize this risk, this study aimed to compare the prevalence of diabetes mellitus (DM) in childhood cancer survivors and their siblings.
METHODS: Participants included 8599 survivors in the Childhood Cancer Survivor Study (CCSS), a retrospectively ascertained North American cohort of long-term survivors who were diagnosed between 1970 and 1986 as well as 2936 randomly selected siblings of the survivors. The main outcome was self-reported DM.
RESULTS: The mean ages of the survivors and the siblings were 31.5 years (age range, 17.0-54.1 years) and 33.4 years (age range, 9.6-58.4 years), respectively. Diabetes mellitus was reported in 2.5% of the survivors and 1.7% of the siblings. After adjustment for body mass index, age, sex, race/ethnicity, household income, and insurance, the survivors were 1.8 times more likely than the siblings to report DM (95% confidence interval [CI], 1.3-2.5; P < .001), with survivors who received total body irradiation (odds ratio [OR], 12.6; 95% CI, 6.2-25.3; P < .001), abdominal irradiation (OR, 3.4; 95% CI, 2.3-5.0; P < .001), and cranial irradiation (OR, 1.6; 95% CI 1.0-2.3; P = .03) at increased risk. In adjusted models, an increased risk of DM was associated with total body irradiation (OR, 7.2; 95% CI, 3.4-15.0; P < .001), abdominal irradiation (OR, 2.7; 95% CI, 1.9-3.8; P < .001), use of alkylating agents (OR, 1.7; 95% CI, 1.2-2.3; P < .01), and younger age at diagnosis (0-4 years; OR, 2.4; 95% CI, 1.3-4.6; P < .01).
CONCLUSION: Childhood cancer survivors treated with total body or abdominal irradiation have an increased risk of diabetes that appears unrelated to body mass index or physical inactivity.