The role of hyperglycemia, insulin resistance, and blood pressure in diabetes-associated differences in cognitive performance - The Maastricht study

OBJECTIVE To study to 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. RESEARCH DESIGN AND METHODS We used cross-sectional data from 2,531 participants from the Maastricht Study (mean age6 SD, 60 6 8 years; 52% men; n = 666 with type 2 diabetes), all of whom completed a neuropsychological test battery. Hyperglycemiawas assessed 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. Linear regression analyses were used to estimate mediating effects. RESULTS 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