Maternal diabetes and childhood cancer risks in offspring: a nationwide cohort study

Maternal diabetes is associated with several adverse childhood outcomes, but its link to childhood cancer remains inconclusive. We investigated this in a nationwide birth cohort using the Korean National Health Insurance database. We analyzed women who delivered singletons between January 2003 and December 2004, and followed their offspring to December, 2021. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for maternal and neonatal factors. Among 549851 women, 33,041 (6.0%) had a diabetic pregnancy. During follow-up, childhood cancer developed in 6049 (1.1%) offspring. No difference was observed in overall risk of cancer incidence between offspring of mothers with or without diabetes (adjusted HR: 1.09, 95% CI 0.99–1.21). However, site-specific analyses revealed an increased relative risk of urinary tract cancer in offspring exposed to maternal diabetes (adjusted HR: 1.81, 95% CI 1.23–2.66). Notably, the absolute risk of urinary tract cancer remained extremely low across the cohort, with an absolute risk difference of only 0.04%. In conclusion, while maternal diabetes is associated with an increased relative risk of childhood urinary tract cancer, the absolute risk is remarkably low, providing clinical reassurance to mothers with diabetes.