Geijselaers SLC, et al. – Researchers conducted a Maastricht Study to present what extent differences in cognitive performance between individuals with different glucose metabolism status are potentially attributable to hyperglycemia, insulin resistance, and blood pressure–related variables. This cross–sectional data demonstrated that early glycemic and blood pressure control, perhaps even in the prediabetic stage, may be promising therapeutic targets for the prevention of diabetes–associated decrements in cognitive performance.

Methods

• Researchers applied cross–sectional data from 2,531 participants from The Maastricht Study (mean age ± SD, 60 ± 8 years; 52% men; n = 666 with type 2 diabetes), all of whom completed a neuropsychological test battery.
• They evaluated hyperglycemia by a composite index of fasting glucose, postload glucose, glycated hemoglobin (HbA1c), and tissue advanced glycation end products; insulin resistance by the HOMA of insulin resistance index; and blood pressure–related variables included 24–h ambulatory pressures, their weighted SDs, and the use of antihypertensive medication.
• They applied linear regression analyses to estimate mediating effects.

Results

• In context of the findings, after adjustment for age, sex, and education, individuals with type 2 diabetes, compared with those with normal glucose metabolism, performed worse in all cognitive domains (mean differences in composite z scores for memory –0.087, processing speed –0.196, executive function and attention –0.182; P values <0.032), whereas individuals with prediabetes did not.
• The results showed that diabetes–associated differences in processing speed and executive function and attention were largely explained by hyperglycemia (mediating effect 79.6% [bootstrapped 95% CI 36.6; 123.4%] and 50.3% [0.6; 101.2%], respectively) and, for processing speed, to a lesser extent by blood pressure–related variables (17.7% [5.6; 30.1%]), but not by insulin resistance.
• In addition, none of the factors explained the differences in memory function.