Association between glycaemic outcome and BMI in Danish children with type 1 diabetes in 2000-2018: a nationwide population-based study

Abstract

Aim: To describe the development of HbA_1c and BMI over time in Danish children with type 1 diabetes; and to investigate the association between HbA_1c and BMI including influence of age, gender, diabetes duration, severe hypoglycaemia and treatment method.

Methods: We used the nationwide Danish Registry of Childhood and Adolescent Diabetes, DanDiabKids, including annual registrations of all children with diabetes treated at Danish hospitals. With linear mixed-effects models and splines we analyzed the HbA_1c and BMI development over time as well as the association between HbA_1c and BMI including effects of gender, age, disease duration, hypoglycaemia and treatment method. BMI z-scores were calculated for these analyses.

Results: For the period from 2000 to 2018, 6097 children with type 1 diabetes were identified from the DanDiabKids database. The median (interquartile range) HbA_1c level was 65 (57-74) mmol/mol (8.1%) and the median BMI z-score was 0.85 in girls and 0.67 in boys. A non-linear association was found between HbA_1c and BMI z-score, with the highest BMI z-score observed for HbA_1c values in the range of approximately 60-70 mmol/mol (7.6-6.8%). The association was modified by gender, age and diabetes duration. Severe hypoglycaemia and insulin pump treatment had a small positive impact on BMI z-score.

Conclusion: The association between HbA_1c and BMI z-score was non-linear, with the highest BMI z-score being observed for intermediate HbA_1c levels; however, specific patterns depended on gender, age and diabetes duration.