The Comparison of Cognitive Function in Hypertensive and Non-Hypertensive in Older Adults

Hypertension and cognitive disorders are common problems in older adults, and their prevalence is increasing with the aging of the population. Therefore, the present study was conducted with the aim of investigating cognitive function in older adults with high blood pressure and older adults without high blood pressure. This study was of causal-comparative type. The statistical population included all older patients with hypertension referred to Farshchian Heart Hospital in Hamedan, Iran. In the present study, sampling was not conducted and eligible patients were examined using the census method and all eligible patients in 2021 who met the inclusion criteria were included in the study and for each patient a control person who did not have high blood pressure was selected (200 people in experimental group and 200 people in the control group). To evaluate cognitive function, Folstein et al.’s Mini Mental State Examination (MMSE) was used. Data were analyzed using SPSS version 24 software. The results showed that cognitive impairment in older patients with high blood pressure was significantly higher than in those without high blood pressure. Moreover, cognitive impairment was significantly higher in women and patients living in rural areas, in divorced and widowed patients, and in patients with high blood pressure with a history of diabetes and stroke. This indicates the effects of high blood pressure on brain function. According to the results, it is necessary to design and implement treatment protocols for older adults with high blood pressure to improve their cognitive function.
EXTENDED ABSTRACT
 Introduction
High blood pressure and cognitive disorders are common issues among older adults, and their prevalence is increasing with the aging population. High blood pressure significantly raises the risk of cardiovascular, cerebrovascular, renal, and other diseases. The prevalence of dementia increases with age, from 5% at age 65 to 20% at age 80 and 40% at age 90. The relationship between blood pressure and cognitive function is complex. High blood pressure predisposes individuals to cognitive decline. Pathophysiologically, an accumulation of cerebrovascular damage and changes in white matter in previously asymptomatic brain lesions may lead to dementia. Recent studies have highlighted the association of high blood pressure with cognitive performance, attention, orientation, memory, and executive function. Epidemiological studies on the relationship between blood pressure, cognitive function and dementia have yielded conflicting results. In some, this relationship is positive, while in others, no significant association was observed. Therefore, given the conflicting results and the importance of cognitive issues and high blood pressure in older adults, the present study aimed to compare the prevalence of cognitive disorders in older adults with and without high blood pressure.
Method
The present study was applied research in terms of its objective and causal-comparative in terms of its method. The statistical population included all older patients with hypertension who referred to Farshchian Heart Hospital in Hamedan, Iran. In this study, sampling was not performed, and eligible patients were included using the census method. All eligible patients in 2021 who met the inclusion criteria were included in the study, and for each patient, a control individual without hypertension was selected (200 individuals in the experimental group and 200 in the control group). The inclusion criteria were: (1) informed consent, (2) age of at least 60 years, and (3) a history of hypertension. The exclusion criteria were: (1) acute cognitive disorders such as Alzheimer’s and dementia, and (2) use of psychiatric medications (for less than 6 months). Participants completed demographic and clinical information forms and Folstein et al.’s Mini Mental State Examination (MMSE). Patients with a systolic blood pressure greater than 140 or a diastolic blood pressure greater than 90 in two measurements at the first visit, or patients undergoing medical treatment for recognized hypertension, were included in the study. For each case, a control individual was selected. The experimental and control groups were matched in terms of age and gender. Data were analyzed using independent t test in SPSS software version 24.
Results
Initially, the normality of cognitive performance scores was assessed using the Shapiro-Wilk test (P>0.05), indicating that this variable is normally distributed in both groups. Table 1 shows that the mean cognitive impairment score of older adults with high blood pressure was significantly lower than that of those without high blood pressure. The results of the comparison between the experimental and control groups based on levels of cognitive impairment are presented in Figure 1.
The results of the ANOVA test indicated that there was no significant difference between the body mass index (BMI) and cognitive impairment scores of patients. Regarding gender, the mean cognitive impairment scores differed significantly between male and female patients. In terms of residence, there was a significant difference in the mean cognitive impairment scores between the two groups, with urban residents showing significantly higher cognitive performance.
Regarding educational level, the results indicated a significant difference among the three groups: high school, diploma, and academic education. Concerning marital status, there was a significant difference in the mean cognitive impairment scores between married patients and those who were divorced or widowed, with married patients scoring significantly higher. Additionally, a significant difference was observed in the mean cognitive performance scores between diabetic and non-diabetic patients. There was no significant difference between the two groups in terms of smoking status. However, regarding the history of heart attack, the mean cognitive impairment scores differed significantly between patients with and without a history of heart attack
Conclusion
The hypothesis of the present study, which posits that cognitive impairments are more prevalent in older patients with hypertension compared to those without it, was confirmed. Higher diastolic and systolic blood pressure levels were associated with a decline in general cognitive performance. Hypertension significantly impacts the regulation of cerebral blood flow, potentially affecting brain structure and function by reducing vascular reserves and exacerbating localized blood supply damage. Consequently, it can be stated that Hypertension-related cognitive impairment arises from an imbalance in the autoregulation of cerebral blood flow and related vascular changes in the brain. Vascular changes due to hypertension affect cerebral blood flow and metabolism. Additionally, conditions such as atherosclerosis and lipohyalinosis can explain the relationship between hypertension and cognitive impairment. Furthermore, age-related abnormalities exacerbate problems with cerebral circulation. The number of cortical brain capillaries decreases, and the basement membrane becomes thicker and more fibrous. These changes lead to reduced cerebral blood flow at rest, diminished cerebral vascular reserves, and inefficiency in the mechanisms regulating cerebral circulation. Hypertension exacerbates age-related changes. Hypertension-related cognitive decline results from the interaction between the reorganization of functional blood flow and vascular damage to the brain
Ethical Consideration
Ethical Code
Ethics Code from Hamadan University of Medical Sciences (IR.UMSHA.REC.1400.163)
Financial Support
 This study had no financial support
Authors’ Contributions

Kh: Supervision, Writing, Review & Editing; M. Ch: Investigation, Software, Writing & Original Draft; S. Kh: Formal Analysis, Validation; F.F: Conceptualization, Data Curation, Project Administration

Conflict of Interest
The authors had no conflicts of interest.
Acknowledgments
Respectful appreciation is extended to the esteemed older participants for their cooperation and assistance in completing the questionnaires.
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