Long-Term Blood Pressure Level and Variability From Midlife to Later Life and Subsequent Cognitive Change: The ARIC...

Background To understand how blood pressure ( BP ) from midlife and beyond is related to cognition in older age, a lifespan approach is needed. We assessed the associations of BP levels and variability from midlife on with subsequent cognitive change. Methods and Results The ARIC (Atherosclerosis Risk in Communities) Study participants underwent 4 clinic BP measurements (visit 1, 2, 3, and 4 BP s) between 1987 and 1998, and their mean levels and average real variability ( ARV ) were assessed as exposures. A global cognitive z score, estimated from the Delayed Word Recall Test, Digit Symbol Substitution Test, and Word Fluency Test scores, was calculated at 1996 to 1998 (visit 4) and 2011 to 2013 (visit 5). Among 11 408 participants (mean age, 54 years; 56% women; 21% black race), mean systolic BP ( SBP )/diastolic BP ( DBP ) level was 123/72 mm Hg, and ARV_SBP / ARV_DBP was 11/7 mm Hg. With linear mixed models, 1- SD increases of ARV_SBP (standardized regression coefficient [95% confidence interval], -0.03 [-0.04 to -0.01] points) and ARV_DBP (standardized regression coefficient [95% confidence interval], -0.02 [-0.03 to -0.002] points; both P<0.05), but not mean SBP or DBP levels, were associated with lower global cognitive z scores at visit 4. In contrast, mean SBP (standardized regression coefficient [95% confidence interval], -0.04 [-0.06 to -0.02] points) or DBP (standardized regression coefficient [95% confidence interval], 0.04 [0.02-0.06] points; both P<0.001) level, but not ARV_SBP or ARV_DBP , was associated with change in global cognitive z scores from visits 4 to 5. Conclusions Greater visit-to-visit SBP or DBP variability from midlife on is modestly associated with lower cognitive function, whereas higher mean SBP and lower DBP levels from midlife to later life are modestly associated with cognitive decline in later life.