Maternal pregestational diabetes and risk of acute lymphoblastic leukemia in the offspring: A population-based study in Northern Italy

•Lymphoblastic leukaemia incidence was 4.7/100,000 children/year in study population.•Maternal age over 40 years was associated with excess childhood leukemia risk.•Risk of childhood leukaemia was considerably higher in children of diabetic mothers. This population-based study aims to evaluate the association between maternal pregestational diabetes and risk of acute lymphoblastic leukemia (ALL) in the offspring. All 241,958 children born in three Northern Italy provinces 1998–2010 were followed from birth until first cancer diagnosis (National Childhood Cancer Register), age 15 years, or 31 December 2017. We computed hazard ratio (HR) and 95% CI of ALL in relation to the presence of maternal diabetes through Cox proportional regression models. We observed 145 cases of ALL, with a higher incidence in children born to women with pregestational diabetes compared to the others (12.4 vs 4.6). Adjusted hazard ratio of ALL was 2.6 (CI, 0.6–10.5) for maternal diabetes. We estimated higher risks of ALL in the offspring of women with pregestational diabetes. These results are consistent with previous findings and compatible with a role of prenatal glycaemic environment in childhood cancer aetiology.