Both low and high 24-hour diastolic blood pressure are associated with worse cognitive performance in type 2 diabetes: The Maastricht Study

P.J.J. Spauwen, M.P.J van Boxtel, F.R.J. Verhey, S. Köhler, S.J.S. Sep, A. Koster, P.C. Dagnelie, R.M.A. Henry, N.C. Schaper, C.J.H. van der Kallen, M.T. Schram, A.A. Kroon, C.D.A. Stehouwer

Hypertension and diabetes are risk factors for cognitive decline and individuals with both might have an especially high risk. We therefore examined linear and nonlinear (quadratic) associations of 24-hour blood pressure with cognitive performance in participants with and without type 2 diabetes (N=713 of whom 201 had diabetes). We also tested the association of nocturnal dipping status with cognitive performance (N=686 of whom 196 had diabetes). Cross-sectional associations were tested with linear regression analysis adjusted for demographics, vascular risk factors, cardiovascular disease, depression, and lipid-lowering and antihypertensive medication use. In the fully adjusted model we found quadratic (inverted U-shaped) associations of 24-hour diastolic blood pressure with information processing speed (regression coefficient b for quadratic term = -0.027, P<0.01) and memory (immediate word recall: b=-0.018, P<0.05; delayed word recall: b=-0.008, P<0.01), and of 24-hour mean arterial pressure with informatin processing speed (b=-0.013, P<0.05) in participants with diabetes, but not in those without. No clear pattern was found for dipping status. This study shows that both low and high 24-hour diastolic blood pressure are associated with poorer performance on tests of information processing speed and memory in individuals with type 2 diabetes.