Since cognitive conditions, including Alzheimer’s, can be impacted by vascular issues, it only makes sense to evaluate if there is a link between hypertension and these diseases. Uncovering this link can not only lead to a better clarification of risk for hypertensive patients, it can answer whether or not treatments for high blood pressure may also be a strategy to prevent Alzheimer’s.
A recent review of studies and research on the subject show that the brains of individuals with a history of hypertension show greater levels of beta amyloid plaques, atrophy and neurofibrillary tangles. But the causal relationship between high blood pressure and Alzheimer’s disease is not completely clear-cut.
Age and its relationship to high blood pressure and dementia
Large epidemiological studies have shown a relationship between patients experiencing high blood pressure in their 40s and 50s and risk for dementia. A comprehensive analysis of study results indicate that middle-aged adults with extended hypertension that include an elevated systolic blood pressure (SBP) over a period of 25–30 years can be put at an exceptionally high risk for cognitive impairment and this impairment is likely to occur as they transition to an elderly adult. This research tends to show that the duration of high blood pressure may play a role in causing cognitive conditions. Untreated hypertension may cause issues for a patient as much as 20-30 years later. But in the case of Alzheimer’s, the research data is more complicated. While there is evidence showing a correlation between elevated diastolic blood pressure (DBP) and the disease, the data on mid-life high SBP is not as solid.
Complicating the issue further is an interesting caveat that comes for patients starting to suffer from hypertension later in life. While hypertension in 60-70 year olds has been associated with cognitive decline, when those studies include patients over 80, that association either fades away, or in certain cases actually suggests that high blood pressure may act as a shield against cognitive issues.
Hypertension Treatment to Prevent Alzheimer’s?
Considering the relationship that’s been established to date between high blood pressure and cognitive issues, it’s only natural to evaluate whether medications to treat hypertension can impact the risk of a patient developing a cognitive disease. There is a body of work that shows little value for these medications as a mitigation strategy for patients in the late stages of life. This can be unsurprising, since those same patients may not have had an increased risk of dementia due to hypertension—if that condition did not start until the late-life stage.
For patients with a hypertension diagnosis and treatment occurring earlier in life, there have been studies that demonstrate the effectiveness of high blood pressure medication in protecting against cognitive conditions and dementia, and frustratingly, others that do not. But there may be hope in finding a clear answer: a meta-analysis of RCTs that compared the neuroprotective properties of different antihypertensive drug classes found angiotensin receptor blockers (ARBs) to be superior to β-blockers, diuretics, and ACE inhibitors for preventing cognitive decline. So it may be the neuroprotective properties of the medications themselves instead of (or in addition to) the ability of these drugs to lower blood pressure.
Finding More Answers
We’re still holding back from strong conclusions about hypertension treatment and its ability to prevent Alzheimer’s and conditions like it. Studies to date have been limited in time and scope and there are a host of other considerations that can impact this relationship, including genetics, demographics—and especially the age of the patient and the duration that they have suffered from high blood pressure. But this work must continue. High blood pressure is treatable, which means that this is a potential Alzheimer’s and dementia risk factor where we can make a difference. The connection between these two conditions is complicated, and one that where we need to increase our understanding in order to positively change a patient’s cognitive condition years before any symptoms appear.
Georgia Memory Net at a Glance
What is Georgia Memory Net and why does it exist? There’s so much information about Alzheimer’s and related dementias in Georgia, and how to diagnose and treat them, that it can become overwhelming. We’ve done our best to simplify the info into a clear one-page infographic.