Hyperglycemia can explain cognitive dysfunction in diabetic patients
The Role of Hyperglycemia, Insulin Resistance, and Blood Pressure in Diabetes-Associated Differences in Cognitive Performance – The Maastricht StudyLiterature - Geijselaers SLC, Sep SJS, Claessens D, et al. - Diabetes Care 2017; published online ahead of print
- An overall trend towards declining cognitive performance was seen with worsening glucose metabolism status, although only those with diabetes had significantly worse cognitive performance.
- Compared with individuals with NGM, T2DM patients performed worse in all cognitive domains (adjusted mean differences in composite z scores for memory: 20.087; processing speed: 20.196; EF&A: 20.182; P values <0.032), but individuals with prediabetes did not.
- The magnitude of diabetes-associated worse performance on memory function was less than half of that observed for processing speed and EF&A, and the differences in memory function were not explained by hyperglycemia or IR, nor by BP–related variables.
- Hyperglycemia explained differences in performance in the domains of processing speed and EF&A between T2DM patients and NGM individuals, with significant mediating effects of 79.6% (bootstrapped 95%CI: 36.6% - 123.4%) and 50.3% (95% CI: 0.6% - 101.2%), respectively.
- Differences in processing speed were also partly explained by BP–related variables (mediating effect: 17.7%; 95% CI: 5.6 - 30.1%), while IR had no mediating effects on the association of T2DM with either processing speed or EF&A.
- The mediating effects of hyperglycemia and BP were partially additive, since any combination of mediators resembled the summed effects of the individual mediators, and the mediating effects of hyperglycemia was more pronounced in patients receiving antihypertensive medications compared with non-users. Moreover, the mediating effects of BP increased with the severity of hyperglycemia.
In participants of the Maastricht study, differences in cognitive performance between T2DM patients and NGM individuals, could be explained by hyperglycemia and partially by BP-related variables, particularly in the domains of processing speed and executive function plus attention, whereas IR has no mediating effects. These findings suggest that the prevention of diabetes-associated deterioration of cognitive performance should focus on early glycemic and BP control.