Substantial Intra-Individual Variability in Post-Prandial Time to Peak in Controlled and Free-Living Conditions in Children with Type 1 Diabetes.

Emily Bell,Elizabeth A Davis,Barbara Keating,Elaine Sanderson,Amelia J Harray,Sabrina Binkowski,Grant Smith

doi:10.3390/nu13114154

Abstract

The optimal time to bolus insulin for meals is challenging for children and adolescents with type 1 diabetes (T1D). Current guidelines to control glucose excursions do not account for individual differences in glycaemic responses to meals. This study aimed to examine the within- and between-person variability in time to peak (TTP) glycaemic responses after consuming meals under controlled and free-living conditions. Participants aged 8–15 years with T1D ≥ 1 year and using a continuous glucose monitor (CGM) were recruited. Participants consumed a standardised breakfast for six controlled days and maintained their usual daily routine for 14 free-living days. CGM traces were collected after eating. Linear mixed models were used to identify within- and between-person variability in the TTP after each of the controlled breakfasts, free-living breakfasts (FLB), and free-living dinners (FLD) conditions. Thirty participants completed the study (16 females; mean age and standard deviation (SD) 10.5 (1.9)). The TTP variability was greater within a person than the variability between people for all three meal types (between-person vs. within-person SD; controlled breakfast 18.5 vs. 38.9 min; FLB 14.1 vs. 49.6 min; FLD 5.7 vs. 64.5 min). For the first time, the study showed that within-person variability in TTP glycaemic responses is even greater than between-person variability.

Highlights

Postprandial hyperglycaemia is a major contributor to overall glycaemic control and glycaemic variability [1]
The current study identified no differences in sex, the menstrual cycle has been associated with cyclical changes in blood glucose levels (BGL) which may further contribute to the variability in female participants [28,29,30]
These factors may explain why the current study found a substantial amount of within-person variability during the controlled conditions, compared to the study conducted by the Children’s Diabetes Centre, which used a precise insulin clamp technique to measure the timing when insulin was required for different meals [15], highlighting the importance of addressing different stages of puberty and its implication on time to peak glycaemic response in a bigger cohort study

Summary

Introduction

Postprandial hyperglycaemia is a major contributor to overall glycaemic control and glycaemic variability [1]. Minimising the time spent above the target blood glucose range has been shown to reduce the risk of long-term micro and macrovascular complications associated with type 1 diabetes (T1D) [2,3]. Achieving optimal post-prandial glucose control requires matching the quantity and the timing of insulin delivery to the appearance of glucose in the bloodstream after a meal. Delivery of meal insulin bolus to achieve optimal glucose levels in the recommended target range (3.9–10 mmol/L) remains a challenge in T1D management for children and adolescents [4,5]. Current international guidelines to control postprandial glucose excursions recommend administering insulin 15 to 20 min before eating [7]. The dose of insulin is calculated using the quantity of carbohydrates in the meal, the glucose level before the meal, and the person’s individualised carbohydrate ratio (ICR) and insulin sensitivity factor (ISF) [4]

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Discussion

Conclusion