Association of Real-Time Glucose Levels and Cognitive Performance in Children with Type 1 Diabetes: A Cross-Sectional Study.

Background/Objectives: Subtle cognitive alterations have been described in children with type 1 diabetes (T1D), but the association between cognition and real-time glycemia during cognitive testing remains unclear. This study aimed to investigate whether blood glucose level (BGL) measured immediately before the MOXO Continuous Performance Test (MOXO-CPT) is associated with cognitive performance and modified by clinical factors. Methods: A total of 117 children with T1D (aged 6-18 years) completed the MOXO-CPT assessing sustained attention, timeliness, impulsivity, and hyperactivity. Participants were stratified by BGL measured immediately before testing (<200 mg/dL [<11.1 mmol/L] vs. ≥200 mg/dL [≥11 mmol/L]). Group comparisons were performed using the Mann-Whitney U test. Multivariable linear regression models examined associations between BGL and cognitive outcomes, adjusting for HbA1c, age, sex, treatment modality and diabetes duration. Interaction analyses were also conducted. Results: In unadjusted group comparisons, participants with BGL ≥ 200 mg/dL demonstrated nominally higher sustained attention (p = 0.036) and timeliness scores (p = 0.040) than those with BGL < 200 mg/dL. However, these differences did not remain statistically significant after Benjamini-Hochberg correction and were not confirmed after adjustment for relevant covariates. No differences were observed in impulsivity or hyperactivity. In multivariable models, higher BGLs were independently associated with higher impulsivity scores (B = 0.013, p = 0.007), with higher scores indicating better impulse-control performance. A significant BGL-sex interaction was observed for timeliness. Sex-stratified analyses showed that higher BGLs were associated with better attention and timeliness in girls, whereas the association with impulsivity observed in boys was not confirmed using robust analysis. No significant interactions between BGL and HbA1c, age, treatment modality, or diabetes duration were observed after robust analysis. Conclusions: Real-time glycemia during cognitive testing was associated with subtle, domain-specific differences in cognitive performance in children with T1D. These findings do not establish causality or indicate that higher glucose levels improve cognitive performance. Concurrent glucose levels may be worth considering when interpreting cognitive assessments, although this should be confirmed in prospective studies.