Ibfelt EH, Vistisen D, Rønn PF, et al. - Using linear mixed‐effects models with splines, researchers intended to determine if there is an association between glycaemic outcomes and BMI in Danish children with type 1 diabetes. In addition, the effects of gender, age, disease duration, hypoglycaemia and treatment method were examined. They used the nationwide Danish Registry of Childhood and Adolescent Diabetes, DanDiabKids, including annual registrations, to identifyHbA1c and BMI over time. Six thousand ninety-seven children with type 1 diabetes were identified from the DanDiabKids database for the period from 2000 to 2018. The relationship between HbA1c and BMI z‐score was non‐linear, with the highest BMI z‐score for intermediate HbA1c levels being observed, but particular trends depended on gender, age and duration of diabetes.