Trajectories of cognition and daily functioning before and after incident diabetes

  

OBJECTIVE

The temporal pattern of cognitive and functional change before and after incident diabetes remains unknown.

RESEARCH DESIGN AND METHODS

Data from wave 2 to wave 9 (2004 to 2018) of the English Longitudinal Study of Ageing were used. Global cognition (assessed by orientation, memory, and executive function) and daily functioning (calculated as the sum of impaired basic and instrumental activities of daily living) were measured in each wave. Incident diabetes was defined as glycated hemoglobin A1c ≥6.5% (47.5 mmol/mol), self-reported doctor-diagnosis diabetes, or glucose-lowering medication use during follow-up.

RESULTS

Among the 6342 participants (mean age 65.0 years, 57.8% women) included, 576 (9.1%) incident diabetes were identified during a median follow-up of 13.3 years. The annual rates of change in global cognition (β = -0.035 SD/year; 95% CI: -0.054 to -0.015), orientation (-0.031 SD/year; -0.060 to -0.002), memory (-0.016 SD/year; -0.029 to -0.003), and executive function (-0.027 SD/year; -0.042 to -0.013) were accelerated after diabetes diagnosis than they did before the event. The post-diabetes annual changes in daily functioning (0.093 point/year; 0.056 to 0.131) were also accelerated compared to before-diabetes diagnosis. However, the rate of cognitive and functional decline before diabetes diagnosis in participants with future incident diabetes was similar to those in diabetes-free participants. Also, no significant acute change was observed during its onset.

CONCLUSIONS

Incident diabetes is associated with accelerated cognitive and functional decline after, but not before, the event. We suggest careful monitoring for cognitive and physical dysfunction after a diabetes diagnosis.