Variability in Body Mass Index during 2018-2021 for People with Type 1 Diabetes: Real World Data from the USA, Germany, and Australasia.

Introduction: The COVID-19 pandemic necessitated worldwide lockdowns in 2020 and 2021, with restrictions on physical activity and changes in eating habits. The aim of this study was to investigate temporal trends in body mass index (BMI) and BMI Standard Deviation Score (SDS) in three international type 1 diabetes (T1D) registries between 2018 and 2021.

Methods: Data were extracted from DPV (Germany/Austria/Luxembourg/Switzerland), T1D Exchange Quality Improvement Collaborative (T1DX-QI, USA), and the Australasian Diabetes Data Network (ADDN, Australia/New Zealand). The period affected by the COVID-19 pandemic was defined as March to December 2020 and March to December 2021 and compared with the respective 9-month periods in 2018 and 2019. Estimated mean BMI (adults ≥19 years) and WHO BMI SDS (children and adolescents 5 to <19 years) were calculated, adjusted for sex, age, HbA1c, and diabetes duration. Adjusted mean proportions overweight (BMI ≥25 in adults or BMI SDS >1 in children and adolescents 5 to <19 years) and obese (BMI ≥30 kg/m2 or BMI SDS >2 in children and adolescents 5 to <19 years) were also calculated, adjusted for sex, age, HbA1c, and diabetes duration.

Results: The study population comprised: ADDN (n = 14,624, median age 15.7 years, 51% male); DPV (n = 62,732, 16.1 years, 53.3% male); and T1DX-QI (n = 22,942, 17.1 years, 52.1% male). In the DPV registry, BMI SDS in children and adolescents and BMI in adults increased consistently between 2018 and 2021 (p < 0.001). In ADDN and T1DX-QI, variable changes in BMI and BMI SDS were seen in adults and young people. Close to 50% of people in all registries were either overweight or obese. Proportions overweight remained relatively stable across the 4 years. The proportion of obesity increased in children 5 to <10 years.

Conclusions: A slight increase in BMI and BMI SDS observed before the pandemic continued during the pandemic years. The proportion of overweight and obesity was overall high. Healthy weight remains a priority for people with T1D.