Systolic Blood Pressure and Cognition in the Elderly: The Northern Manhattan Study

Association of Blood Pressure With Brain Ages: A Cohort Study of Gray and White Matter Aging Discrepancy in Mid-to-Older Adults From UK Biobank

BACKGROUND

Gray matter (GM) and white matter (WM) impairments are both associated with raised blood pressure (BP), although whether elevated BP is differentially associated with the GM and WM aging process remains inadequately examined.

METHODS

We included 37 327 participants with diffusion-weighted imaging (DWI) and 39 630 participants with T1-weighted scans from UK Biobank. BP was classified into 4 categories: normal BP, high-normal BP, grade 1, and grade 2 hypertension. Brain age gaps (BAGs) for GM (BAGGM) and WM (BAGWM) were derived from diffusion-weighted imaging and T1 scans separately using 3-dimensional-convolutional neural network deep learning techniques.

RESULTS

There was an increase in both BAGGM and BAGWM with raised BP (P<0.05). BAGWM was significantly larger than BAGGM at high-normal BP (0.195 years older; P=0.006), grade 1 hypertension (0.174 years older; P=0.004), and grade 2 hypertension (0.510 years older; P<0.001), but not for normal BP. Mediation analysis revealed that the association between hypertension and cognitive decline was primarily mediated by WM impairment. Mendelian randomization analysis suggested a causal relationship between hypertension and WM aging acceleration (unstandardized B, 1.780; P=0.016) but not for GM (P>0.05). Sliding-window analysis indicated the association between hypertension and brain aging acceleration was moderated by chronological age, showing stronger correlations in midlife but weaker associations in the older age.

CONCLUSIONS

Compared with GM, WM was more vulnerable to raised BP. Our study provided compelling evidence that concerted efforts should be directed towards WM damage in individuals with hypertension in clinical practice.

Optimal cardiovascular health is associated with slower cognitive decline

BACKGROUND

Life's Simple 7, a lifestyle and cardiovascular index associated with cognition, has been updated to Life's Essential 8 (LE8) to include sleep. LE8 has been related to cardiovascular outcomes but its association with cognition is unclear.

METHODS

In this longitudinal analysis of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), LE8 score was based on health behaviors (diet, physical activity, nicotine exposure, and sleep health) as well as health-related factors (body mass index, blood lipids, blood glucose, and blood pressure). Cognition was assessed in three waves, 4 years apart, using the Consortium to Establish a Registry for Alzheimer's Disease - Word List, semantic and phonemic verbal fluency, the Trail-Making Test B (TMT-B), and a global composite score. We used linear mixed-model analysis, inverse probability weighting, and interaction analysis.

RESULTS

At baseline, the mean age of the study cohort was 51.4 ± 8.9 years, 56% were women, and 53% were White. Higher baseline LE8 scores were associated with slower decline in global cognition (β = 0.001, 95% confidence interval [CI] 0.001, 0.002; p < 0.001), memory (β = 0.001, 95% CI 0.000, 0.002; p = 0.013), verbal fluency (β = 0.001, 95% CI 0.000, 0.002; p = 0.003), and TMT-B (β = 0.004, 95% CI 0.003, 0.005; p < 0.001). This association was mainly driven by LE8 health factors, particularly blood glucose and blood pressure. Age, sex, and race were modifiers of the association between LE8 and global cognitive decline (p < 0.001), suggesting it was more pronounced in older, male, and Black participants.

CONCLUSIONS

Higher baseline LE8 scores were associated with slower global and domain-specific cognitive decline during 8 years of follow-up, mainly due to health factors such as blood glucose and blood pressure. Sociodemographic factors were modifiers of this association.

Treatment of hypertension and obstructive sleep apnea counteracts cognitive decline in common neurocognitive disorders in diagnosis-related patterns

The aim of this study was to investigate the effect of arterial hypertension (AH) and of obstructive sleep apnea (OSA) on cognitive course in the neurocognitive disorder (NCD) cohort RIFADE which enrolled patients with NCD due to Alzheimer's disease (AD), vascular NCD (vNCD), and mixed NCD (AD + vNCD = mNCD). Multiple risk factors (RF), including AH and OSA, that contribute to the development of various kinds of dementia have been identified in previous studies. Studies that observed AH lacked investigation of long-term effects and did not isolate it from other RF. Studies involving OSA as a risk factor did not include participants with all stages of NCD. 126 subjects were screened for AH and OSA. Repeated cognitive measurements were performed with the DemTect as primary outcome and the clock drawing test as secondary outcome measure. 90 patients had AH (71.4%) and 40 patients had OSA (31.7%). RF-status had a significant effect on cognitive outcome in models with RF as single factors (AH p = 0.027, OSA p < 0.001), a 2-factor analysis with AH × OSA (AH as main factor p = 0.027) as well as a model including the 3 factors AH × OSA × diagnosis (p = 0.038). Similarly, a 3-factor model was significant for the clock-drawing test, whereas single factor-models remained insignificant. AH and OSA appear to be risk factors in common NCD and cognitive decline can be mitigated by treatment of these RF.

White matter changes underlie hypertension-related cognitive decline in older adults

Hypertension has been well recognized as a risk factor for cognitive impairment and dementia. Although the underlying mechanisms of hypertension-affected cognitive deterioration are not fully understood, white matter changes (WMCs) seem to play an important role. WMCs include low microstructural integrity and subsequent white matter macrostructural lesions, which are common on brain imaging in hypertensive patients and are critical for multiple cognitive domains. This article provides an overview of the impact of hypertension on white matter microstructural and macrostructural changes and its link to cognitive dysfunction. Hypertension may induce microstructural changes in white matter, especially for the long-range fibers such as anterior thalamic radiation (ATR) and inferior fronto-occipital fasciculus (IFOF), and then macrostructural abnormalities affecting different lobes, especially the periventricular area. Different regions' WMCs would further exert different effects to specific cognitive domains and accelerate brain aging. As a modifiable risk factor, hypertension might provide a new perspective for alleviating and delaying cognitive impairment.

Diastolic Blood Pressure and Cognitive Functioning: Differences by Systolic Blood Pressure Among US Adults

BACKGROUND

The role of diastolic blood pressure (DBP) with cognitive functioning is under-explored in relation to levels of systolic blood pressure (SBP).

METHODS

We studied 5466 participants from the National Health and Nutrition Examination Survey. Blood pressure was measured 3 times manually with a standardized sphygmomanometer and averaged. Cognitive functioning was measured using the digit symbol substitution test (DSST).

RESULTS

Participants were 60 years or older, 55% female, and 81% non-Hispanic White. Most participants had a DBP between 70 to <80 mmHg (33.7%), between 60 to <70 mmHg (29.3%), or <60 mmHg (18.8%). From multivariable linear regression analyses, each 5 mmHg increment of DBP was associated with significantly higher DSST scores among individuals with SBP <120 only (ß: 0.56, 95% CI: 0.09, 1.03).

CONCLUSIONS

Among older US adults, at non-elevated levels of SBP, higher DBP is associated with better cognitive performance.

Vascular Cognitive Impairment (VCI)

Vascular cognitive impairment (VCI) is predominately caused by vascular risk factors and cerebrovascular disease. VCI includes a broad spectrum of cognitive disorders, from mild cognitive impairment to vascular dementia caused by ischemic or hemorrhagic stroke, and vascular factors alone or in a combination with neurodegeneration including Alzheimer's disease (AD) and AD-related dementia. VCI accounts for at least 20-40% of all dementia diagnosis. Growing evidence indicates that cerebrovascular pathology is the most important contributor to dementia, with additive or synergistic interactions with neurodegenerative pathology. The most common underlying mechanism of VCI is chronic age-related dysregulation of CBF, although other factors such as inflammation and cardiovascular dysfunction play a role. Vascular risk factors are prevalent in VCI and if measured in midlife they predict cognitive impairment and dementia in later life. Particularly, hypertension, high cholesterol, diabetes, and smoking at midlife are each associated with a 20 to 40% increased risk of dementia. Control of these risk factors including multimodality strategies with an inclusion of lifestyle modification is the most promising strategy for treatment and prevention of VCI. In this review, we present recent developments in age-related VCI, its mechanisms, diagnostic criteria, neuroimaging correlates, vascular risk determinants, and current intervention strategies for prevention and treatment of VCI. We have also summarized the most recent and relevant literature in the field of VCI.