Abstract
Introduction: Blood glucose (BG) regulation is linked to cognitive performance among people with diabetes. Most studies are cross-sectional and limited to adults with T2D. Pairing continuous glucose monitoring (CGM) with ambulatory cognitive tests, we examined real-time bidirectional associations between BG and cognition in everyday life among adults with T1D. Methods: Participants wore a blinded CGM for 10-14 days and completed ambulatory cognitive tests 5-6 times daily. Using dynamic structural equation modeling, we evaluated within-person bidirectional relationships between BG and cognition over sequential 3-hr periods. BG metrics included mean BG, time in range (TIR; 70-180 mg/dL), % time in low (50-69 mg/dL), high (181-250 mg/dL) and very high BG (>250 mg/dL), and coefficient of variation (CV). Cognitive variables included processing speed and sustained attention. Results: Among 182 adults with T1D (40±14 yrs, 46% male, 41% Latino, 29% White, 15% Black), greater mean BG (beta=0.03), lower TIR (beta=-0.03), and more time in high (beta=0.03) and very high BG (beta=0.03) predicted slower processing speed 3 hrs later (ps<.05); no BG metric predicted sustained attention ability. Surprisingly, slower processing speed predicted lower mean BG (beta=-0.05), more TIR (beta=0.04) and less time in high (beta=-0.01) and very high BG (beta=-0.04) over the next 3 hrs. Reduced sustained attention predicted more time in very high BG (beta=-0.01) and lower CV (beta=0.03) (ps<0.05). Conclusion: Our findings suggest that poorer BG regulation negatively influences processing speed over short time frames. Slower processing speed predicted subsequent improvements in CGM metrics, suggesting that individuals may take steps to correct BG when experiencing cognitive effects of poor BG regulation. These short-term relationships illuminate opportunities for in-the-moment interventions.