Glucose Variability and Postprandial Hyperglycaemia After Breakfast in Children and Young People With Type 1 Diabetes

Aims: This study aimed to describe glucose variability (GV) and explore postprandial glycaemia and the association with food composition following breakfast in children and young people (CYP) with type 1 diabetes (T1D). Methods: This was an observational study of CYP aged 1–17 years using continuous glucose monitoring (CGM). Retrospective CGM data were collected to assess GV along with questionnaires about the breakfast meal and 4‐h postprandial period for 7 days. Statistical analysis included Student’s t ‐tests and linear mixed models. Results: Ninety‐six CYP were recruited, 89 shared their CGM data (mean age 10.1 ± 3.8 years) (44.9% females), of which 74 submitted questionnaires. Diurnal percentage coefficient of variation (%CV) (mean: 38.1% ± 4.3%) was significantly higher than nocturnal %CV (36.4 ± 5.2) (95% confidence interval [CI] [0.9, 2.5], Cohen d = 0.5, p < 0.001). Continuous subcutaneous insulin infusion (CSII) users had a significantly higher time in range (TIR) (mean: 61.7% ± 11.0%) than those using multiple daily injections (MDIs) (mean: 55.5% ± 15.0%) (95% CI [0.2, 12], Cohen’s d = 0.5, p = 0.04). Data on 387 breakfast meals were analysed. The preprandial glucose was significantly lower for CSII users (mean: 7.4 ± 2.3 mmol/L) compared with MDI users (mean: 9.5 ± 2.9 mmol/L) (95% CI [1.3,3.3], d = 0.9, p < 0.001). Preprandial glucose was significantly associated with mean postprandial glucose ( R 2 = 0.27, p < 0.001). Compared with breakfast meals containing a protein food ( n = 71), ingested meals containing breakfast cereals only ( n = 76) resulted in a significantly higher mean postprandial glucose ( p = 0.01), peak excursion ( p = 0.03), area under the curve (AUC) ( p = 0.03) and time above range (TAR) ( p < 0.001) and significantly shorter time to peak ( p = 0.01) and lower TIR ( p = 0.01). Ingested meals containing only breakfast cereals also resulted in significantly higher glucose excursion at 30, ( p < 0.001), 60 ( p < 0.001) and 90 min ( p = 0.02) compared with breakfast meals containing a protein food. Conclusions: GV is significantly higher in the diurnal period. Managing T1D with CSII and including a protein food in the breakfast meal may reduce postprandial hyperglycaemia after breakfast in CYP with T1D. The trial was registered retrospectively with Clinicaltrials.gov (10/08/2024): NCT06546657.