Trajectory patterns of blood pressure change up to six years and the risk of dementia: a nationwide cohort study

Hypertension and Cognitive Disorders

Systemic hypertension is possibly the most important modifiable risk factor for the development of cognitive decline, both for mild cognitive impairment (MCI) and dementia. For effective blood pressure (BP) control, it requires proper assessment, using brachial, central, and ambulatory measurements, and monitoring with a focus on different BP parameters. Different BP parameters like pulse pressure, mean arterial pressure, BP variability, and circadian parameters, like nondippers and early morning surge, should be considered in the evaluation for the risk of cognitive decline due to hypertension in middle age and older adults. Chronic hypertension causes vascular remodeling in the brain and leads to brain failure or cognitive decline. Achieving specific BP goals can improve clinical outcomes and possibly slow down cognitive decline for patients with comorbid hypertension and cognitive impairment.

Associations between long-term blood pressure trajectory and all-cause and CVD mortality among old people in China

Background

Optimal blood pressure (BP) management strategy among the elderly remains controversial, with insufficient consideration of long-term BP trajectory. This study aimed to identify BP trajectory patterns as well as terminal BP trajectory among the Chinese elderly and to explore the relationships between BP trajectories and all-cause mortality and cardiovascular disease (CVD) mortality.

Methods

We included 11,181 participants older than 60 at baseline (mean age, 80.98 ± 10.71) with 42,871 routine BP measurements from the Chinese Longitudinal Healthy Longevity Survey. Latent class trajectory analysis and Cox proportional hazard model were conducted to identify trajectory patterns and their associations with mortality. Furthermore, we also applied mixed-effects model to identify terminal BP trajectories among the elderly.

Results

Compared with stable at normal high level trajectory, excess systolic BP (SBP) trajectory with decreasing trend was associated with a 34% (HR = 1.34, 95% CI: 1.23-1.45) higher risk of all-cause mortality. Considering the competing risk of non-CVD death, excess BP trajectory with decreasing trend had a more pronounced effect on CVD mortality, in which HR (95% CI) was 1.67 (1.17, 2.37). Similar results were also found in diastolic BP (DBP), pulse pressure (PP), and mean arterial pressure (MAP) trajectories. We further conducted a mixed-effects model and observed that SBP and PP trajectories first increased and began to decline slightly six years before death. In contrast, DBP and MAP showed continuous decline 15 years before death.

Conclusion

Long-term BP trajectory was associated with all-cause mortality, especially CVD mortality. Keeping a stable BP over time may be an important way for CVD prevention among the elderly.

Pathophysiological Association of Alzheimer's Disease and Hypertension: A Clinical Concern for Elderly Population

Alzheimer's disease (AD), the most common cause of dementia and the fifth leading cause of death in the adult population has a complex pathophysiological link with hypertension (HTN). A growing volume of published literature on a parallel elevation of blood pressure (BP), amyloid plaques, and neurofibrillary tangles formation in post-middle of human brain cells has developed new, widely accepting foundations on this association. In particular, HTN in elderly life mediates cerebral blood flow dysfunction, neuronal dysfunction, and significant decline in cognitive impairment, primarily in the late-life populace, governing the onset of AD. Thus, HTN is an established risk factor for AD. Considering the impact of AD, 1.89 million deaths annually, and the failure of palliative therapies to cure AD, the scientific research community is looking to adopt integrated approaches to target early modified risk factors like HTN to reduce AD burden. The current review highlights the significance and impact of HTN-based prevention in lowering the AD burden in the elderly by providing a comprehensive overview of the physiological relationship between AD and HTN with an in-detail explanation of the role and applications of pathological biomarkers in this clinical association. The review will gain worth in presenting new insights and providing inclusive discussion on the correlation between HTN and cognitive impairment. It will increase across a wider scientific audience to expand understanding of this pathophysiological association.

Central obesity and elevated blood pressure in middle life are associated with physical and cognitive impairment in later life: A retrospective design with repeated measures

BACKGROUND AND AIMS

Physical and cognitive function decline indicates the prestage of disability and is associated with mortality among older adults. We investigated the association of metabolic disorders in midlife with physical and cognitive function decline in later life in a retrospective cohort.

MATERIAL AND METHODS

A total of 618 older adults aged ≥60 years in wave-6 (2014-2017) were enrolled in the Cardiovascular Disease Risk Factor Two-Township Study to evaluate physical (hand grip strength and 4-m walking speed) and cognitive function (Mine-Mental State Examination [MMSE] score). Repeated metabolic disorder measures in wave-2, wave-3, and wave-5 were obtained to identify three trajectory pattern groups according to each metabolic disorder through group-based trajectory modeling. Linear and logistic regressions were conducted to investigate the association of metabolic disorders in middle life with physical and cognitive function decline in later life.

RESULTS

The prevalence rates of a weak hand grip (<28 kg for men and <18 kg for women), slow walking speed (<0.8 m/s), and poor cognitive function (MMSE <25) were 24.43 %, 16.83 % and 10.5 %, respectively, among the older adults. In the retrospective cohort with 15-year follow-up, those with a waist circumference of ≥95 cm for men and ≥85 cm for women in middle life exhibited a significantly weak hand grip (odds ratio: 2.78 [95 % confidence interval: 1.26, 6.11]) and slow walking speed (2.26 [1.15, 4.43]) in later life compared with those with a smaller waist circumference (<85 cm for men and <75 cm for women). Elevated blood pressure (systolic blood pressure [BP] ≥130 mmHg or diastolic BP ≥80 mmHg) was significantly associated with a higher risk of cognitive function decline in later life. Furthermore, the high-trajectory and middle-trajectory groups' body mass index (3.17 [1.25, 8.04] and 2.27 [1.28, 4.00], respectively) and waist circumference (4.39 [2.07, 9.31] and 2.54 [1.39, 4.67], respectively) were significantly associated with a weak hand grip and slow walking speed, respectively, compared with those of the low-trajectory group. The high-trajectory diastolic BP group was significantly associated with a higher risk of cognitive function decline compared with the low-trajectory diastolic BP group.

CONCLUSION

Waist circumference and BP in middle life were associated with physical function decline and poor cognitive function in later life. The management of central obesity and BP in midlife may slow the decline of physical and cognitive function in later life.

Associations between trajectories of cardiovascular risk factor change and cognitive impairment in Chinese elderly: A nationwide cohort study

Objectives

This study aimed to investigate the relationship between long-term trajectories of changes in cardiovascular risk factors (CVRFs) and the risk of cognitive impairment among Chinese adults over 60 years old.

Methods

Data were obtained from the Chinese Longitudinal Healthy Longevity Survey 2005-2018. Cognitive function was evaluated longitudinally through the Chinese version of the Mini-Mental State Examination (C-MMSE), and cognitive impairment (C-MMSE ≤23) was used as the main outcome variable. The cardiovascular risk factors, including systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP), and body mass index (BMI), were continuously measured in the follow-up duration. The patterns of trajectories of changes in CVRFs were derived from the latent growth mixture model (LGMM). The Cox regression model was used to evaluate the cognitive impairment hazard ratio (HR) across different CVRF trajectories.

Results

A total of 5,164 participants aged ≥60 years with normal cognitive function at baseline were included in the study. After a median follow-up of 8 years, 2,071 participants (40.1%) developed cognitive impairment (C-MMSE ≤ 23). The four-class trajectories of SBP and BMI were obtained by means of LGMM, and the trajectories of DBP, MAP, and PP were grouped into a three-class subgroup. In the final adjusted Cox model, the lowered SBP [adjusted HR (aHR): 1.59; 95% CI: 1.17-2.16], lowered PP (aHR: 2.64; 95% CI: 1.66-4.19), and progressively obese (aHR: 1.28; 95% CI: 1.02-1.62) and stable slim (aHR: 1.13; 95% CI: 1.02-1.25) were associated with the higher risk of cognitive impairment. Low stable DBP (aHR: 0.80; 95% CI: 0.66-0.96) and elevated PP (aHR: 0.76; 95% CI: 0.63-0.92) decreased the risk for cognitive impairment among participants.

Conclusion

Lowered SBP, lowered PP, progressive obesity, and stable slim increased the risk for cognitive impairment in the Chinese elderly. Low stable DBP and elevated PP were protective against cognitive impairment, but more DBP lowering and ≥25 mmHg growth in PP contributed to a higher risk of cognitive impairment. The findings have important implications for preventing cognitive impairment in elder adults based on the long-term trajectories of changes in CVRFs.

The association of pulse pressure change with memory decline in middle-aged and older adults

BACKGROUND

Less is known regarding the association of pulse pressure (PP) with memory function. This study aimed to characterize long-term patterns of PP in middle-aged and older adults and explore their impact on subsequent change in memory function.

METHODS

Data from the English Longitudinal Study of Ageing (ELSA, 2004-2018), were analyzed. Totally, 3587 dementia-free participants with three measurements of BP were included. All three visits of PP (2004-2012) were used to characterize longitudinal patterns of PP by group-based trajectory modeling (GBTM). Generalized estimating equation (GEE) models were fitted to explore the impact of PP trajectories on change in memory over a subsequent 6-year period (2012-2018).

RESULTS

Using GBTM, three distinct trajectories of PP were identified: low-stable (38.1%), moderate-stable (48.6%), and elevated-increasing group (13.3%). GEE model suggested that memory declined over a 6-year period in all PP trajectories (all P_time  <0.001). The overall interactions between patterns of PP changes and time with memory were statistically significant (χ² _interaction  = 20.69, p = 0.002). Compared to participants in the low-stable group, those in the moderate-stable and elevated-increasing group exhibited a faster decline in memory.

CONCLUSIONS

Longitudinal patterns of moderate-stable and elevated-increasing PP were associated with an accelerated decrease in memory. Controlling BP instability may be a promising interventional strategy for preventing cognitive decline among older adults.

Elevated late-life blood pressure may maintain brain oxygenation and slow amyloid-β accumulation at the expense of cerebral vascular damage

Hypertension in midlife contributes to cognitive decline and is a modifiable risk factor for dementia. The relationship between late-life hypertension and dementia is less clear. We have investigated the relationship of blood pressure and hypertensive status during late life (after 65 years) to post-mortem markers of Alzheimer's disease (amyloid-β and tau loads); arteriolosclerosis and cerebral amyloid angiopathy; and to biochemical measures of ante-mortem cerebral oxygenation (the myelin-associated glycoprotein:proteolipid protein-1 ratio, which is reduced in chronically hypoperfused brain tissue, and the level of vascular endothelial growth factor-A, which is upregulated by tissue hypoxia); blood-brain barrier damage (indicated by an increase in parenchymal fibrinogen); and pericyte content (platelet-derived growth factor receptor β, which declines with pericyte loss), in Alzheimer's disease (n = 75), vascular (n = 20) and mixed dementia (n = 31) cohorts. Systolic and diastolic blood pressure measurements were obtained retrospectively from clinical records. Non-amyloid small vessel disease and cerebral amyloid angiopathy were scored semiquantitatively. Amyloid-β and tau loads were assessed by field fraction measurement in immunolabelled sections of frontal and parietal lobes. Homogenates of frozen tissue from the contralateral frontal and parietal lobes (cortex and white matter) were used to measure markers of vascular function by enzyme-linked immunosorbent assay. Diastolic (but not systolic) blood pressure was associated with the preservation of cerebral oxygenation, correlating positively with the ratio of myelin-associated glycoprotein to proteolipid protein-1 and negatively with vascular endothelial growth factor-A in both the frontal and parietal cortices. Diastolic blood pressure correlated negatively with parenchymal amyloid-β in the parietal cortex. In dementia cases, elevated late-life diastolic blood pressure was associated with more severe arteriolosclerosis and cerebral amyloid angiopathy, and diastolic blood pressure correlated positively with parenchymal fibrinogen, indicating blood-brain barrier breakdown in both regions of the cortex. Systolic blood pressure was related to lower platelet-derived growth factor receptor β in controls in the frontal cortex and in dementia cases in the superficial white matter. We found no association between blood pressure and tau. Our findings demonstrate a complex relationship between late-life blood pressure, disease pathology and vascular function in dementia. We suggest that hypertension helps to reduce cerebral ischaemia (and may slow amyloid-β accumulation) in the face of increasing cerebral vascular resistance, but exacerbates vascular pathology.

Initiation of Antihypertensive Medication from Midlife on Incident Dementia: The Health and Retirement Study

BACKGROUND

Hypertension has been identified as a risk factor of dementia, but most randomized trials did not show efficacy in reducing the risk of dementia. Midlife hypertension may be a target for intervention, but it is infeasible to conduct a trial initiating antihypertensive medication from midlife till dementia occurs late life.

OBJECTIVE

We aimed to emulate a target trial to estimate the effectiveness of initiating antihypertensive medication from midlife on reducing incident dementia using observational data.

METHODS

The Health and Retirement Study from 1996 to 2018 was used to emulate a target trial among non-institutional dementia-free subjects aged 45 to 65 years. Dementia status was determined using algorithm based on cognitive tests. Individuals were assigned to initiating antihypertensive medication or not, based on the self-reported use of antihypertensive medication at baseline in 1996. Observational analog of intention-to-treat and per-protocol effects were conducted. Pooled logistic regression models with inverse-probability of treatment and censoring weighting using logistic regression models were applied, and risk ratios (RRs) were calculated, with 200 bootstrapping conducted for the 95% confidence intervals (CIs).

RESULTS

A total of 2,375 subjects were included in the analysis. After 22 years of follow-up, initiating antihypertensive medication reduced incident dementia by 22% (RR = 0.78, 95% CI: 0.63, 0.99). No significant reduction of incident dementia was observed with sustained use of antihypertensive medication.

CONCLUSION

Initiating antihypertensive medication from midlife may be beneficial for reducing incident dementia in late life. Future studies are warranted to estimate the effectiveness using large samples with improved clinical measurements.