## 4 Discussion
### Alzheimer's Disease and Cardiovascular Risk Factors
#### 4.2.1 High Blood Pressure and Alzheimer's Disease  
HBP has been identified as a factor affecting the vascular integrity of the blood-brain barrier, resulting in an impaired blood-brain barrier, leading to brain cell damage with increased A\(\beta\)-peptide deposition, hypoperfusion and neuroinflammation, and leading to impaired memory abilities [45]. In the epidemiological study conducted by [PERSON] et al. [46], the relationship between HBP and AD was observed, while blood pressure variations in individuals diagnosed with AD before and after the onset of the disease were analysed. The results revealed a significant association between HBP and AD prevalence, finding a higher prevalence of AD in those participants with HBP, especially in the group with systolic blood pressure greater than or equal to 170 mmHg (\(p<0.0002\)). In addition, HBP contributed 28.3% to the incidence of new AD cases, suggesting that approximately 1/3 of new AD cases could be related to elevated blood pressure. They compared blood pressure values between cases diagnosed with AD and individuals without a diagnosis of dementia, finding that the blood pressure values of the AD group were significantly higher than those of the CG (without dementia). The odds ratio (OR) for the group with systolic blood pressure greater than or equal to 140 mmHg and less than 170 mmHg was 1.70, while for the other group with systolic blood pressure greater than 170 mmHg, the OR was 2.52. The results of this study were consistent with the findings obtained in previous studies [45], suggesting a positive association between HBP and AD. In the present investigation, it is observed that the percentage of individuals with HBP in the group of cases with AD (39.19%) is significantly higher compared to the group of healthy individuals (24.60%). This difference in percentages shows a statistically significant association, suggesting that the presence of HBP could be related to AD in the sample studied [46]. [PERSON] et al. [47] conducted a recent study focusing on the impact of vascular risk factors and the severity of A\(\beta\)-peptide plaques in the brain, measured in vivo in 635 participants of the Rotterdam study. Vascular risk factors were assessed 7 and 13 years prior to brain scanning via PET. Their results showed an association between vascular risk factors and increased levels of brain A\(\beta\)-peptide, especially in ApoE4 gene carriers. Two meta-analyses support the association between high blood pressure and AD [48; 49]. [PERSON] et al. [48] found grade I evidence suggesting an association between medical history, such as HBP, hypotension and type 2 DM, and a risk of developing AD. In 2020, the study carried by [PERSON] et al. [49] identified significant associations between HBP in middle-aged individuals and cognitive function. Systolic blood pressure above 130 mmHg was associated with a relative risk (RR) of 1.19 and 1.55 for cognitive impairment. Regarding dementia, moderate evidence showed a significantly elevated risk (RR: 1.20) associated with HBP in these individuals, also with elevated systolic blood pressure (RR: 1.50) and excessive change in diastolic blood pressure (RR: 1.65). The authors indicated that a systolic blood pressure greater than or equal to 140 mmHg, a diastolic blood pressure greater than or equal to 80 mmHg and a change in diastolic blood pressure of more than 5 mmHg were associated with a 37% to 52% increased risk of AD. If the relationship between AD and HBP is accepted, lowering blood pressure levels should have a protective effect. Therefore, [PERSON] et al. [50] reported that antihypertensive treatments have a beneficial effect on AD, delaying the onset of cognitive decline. Also, [PERSON] et al. [49] collected studies indicating that antihypertensive drugs were associated with a 21% reduction in the risk of dementia. HBP is a risk factor for developing AD in old age due to an increase in the deposition of A\(\beta\)-peptide and neurofibrillary tangles in the cerebral blood vessels [51].