The Effect of Blood Pressure on Cognitive Performance. An 8-Year Follow-Up of the Tromsø Study, Comprising People Aged 45–74 Years

Abstract

Background: The relationship between blood pressure (BP) and cognition is complex were age appears to be an intervening variable. High and low BP have been associated with cognitive deficits as part of the aging process, but more studies are needed, especially in more recent birth cohorts. Methods:The study sample comprised 4,465 participants, with BP measured at baseline in the Tromsø Study, Wave 6 in 2007-2008 (T0), and cognition assessed at follow-up 8 years later, in 2015-2016 in Tromsø Study 7 (T1). Age at T0 was 45-74 years, and at T1 it was 53-82 years. Cognition was assessed with three tests: The Mini Mental State Examination (MMSE), the Digit Symbol Test, and the Twelve-word Test. The associations between BP and cognition were examined specifically for age and sex using linear regression analysis adjusted for baseline BP medication use, education and body mass index (kg/m 2 ).Results: BP was associated with cognition at the 8-year follow-up, but the association differed according to age and sex. In men, higher systolic blood pressure (SBP) and diastolic blood pressure (DBP) at a young age (45-55 years of age) was associated with poorer cognition; the association was reversed at older ages, especially for those above 65 years of age. In women, the associations were generally weaker than for men, and sometimes in the opposite direction: For women, a higher SBP was associated with better cognition at a younger age and higher SBP poorer cognition at older ages -perhaps due to an age delay in women compared to men. Digit Symbol Test results correlated best with BP in a threeway interaction: BP by age by sex was significant for both SBP (p = 0.005) and DBP (p = 0.005).Frontiers in Psychology | www.frontiersin.org April 2020 | Volume 11 | Article 607 Hestad et al. Blood Pressure and CognitionConclusion: Increased SBP and DBP at the younger age was clearly associated with poorer cognitive function in men 8 years later; in women the associations were weaker and sometimes in the opposite direction. Our findings clearly indicate that interactions between age and sex related to BP can predict cognitive performance over time. Men and women have different age trajectories regarding the influence of BP on cognition.

Hypertension-induced cognitive impairment: from pathophysiology to public health

“…The cognitive domains that are negatively affected by hypertension include abstract reasoning and/or executive function , memory and mental processing speed 3 . A study that used the Digit Symbol Substitution Test , which is a more sensitive measure of cognitive impairment than the Mini-Mental State Examination (MMSE), showed that in men aged 45–55 years, higher SBP and DBP were significantly associated with lower cognitive performance at 8 years of follow-up 25 . In women, higher SBP was associated with better cognition at younger ages and poorer cognition at older ages.…”

Blood pressure in dementia, mild cognitive impairment, and subjective cognitive decline related to time of death

“…It is more likely that the tendency for decline in SBP closer to death in men can be related to differences in cardio‐vascular differences between the sexes. It has for a long time been known that men have a lower survival rate than females after a diagnosis of dementia (Rizzuto et al, 2012) and there are differences in blood pressure development, cardio vascular disease, and myocardial incident of infarction between the sexes as they age (Albrektsen et al, 2016; Barrett‐Connor, 2013; Hestad, Engedal, Schirmer, et al, 2020). It is seen that there is an accelerated risk of myocardial infarction in young men compared to young women.…”

“…It is known that blood pressure drops as people approach death (Delgado et al, 2018; Goodwin, 2018; Hestad et al, 2020). Delgado et al, among others, have demonstrated in people over the age of 60 that blood pressure begins a downward trajectory more than 10 years before death, with the steepest declines occurring 2 years prior to death (Delgado et al, 2018).…”

“…Studies indicate that the relationship between cognitive impairment and either high or low blood pressure (BP) are more clearly found in men than in women, even though women have the largest change in blood pressure during aging (Barrett‐Connor, 2013; Hestad, Engedal, Schirmer, et al, 2020; Joyner et al, 2016).…”

Blood Pressure in Different Dementia Disorders, Mild Cognitive Impairment, and Subjective Cognitive Decline

“…We found an interaction between age and sex for SBP at younger ages, in that women start out with a lower pressure but end up with a higher blood pressure than men. It is seen from population studies that men and women show differential developmental trajectories regarding BP regulations over a lifetime ( Joyner et al, 2016 ; Hestad et al, 2020 ). In the present study there were significant differences between men and women in blood pressure development.…”