New Study Shows Connection Between Cardiovascular Disease and Alzheimer's Risk

High blood pressure, also called hypertension, is a known risk factor for heart attack, stroke, and vascular damage. The study shows that high blood pressure can damage the small blood vessels in the brain, impair the blood-brain barrier, and increase the risk of strokes as well as damage to small vessels. Such vascular changes can limit memory, attention, and general cognitive performance.

In addition to high blood pressure, the researchers also examined cardiac arrhythmias, heart failure, stroke, and heart attack. Cardiac arrhythmias and heart failure likewise showed a connection with later Alzheimer's diagnoses. Acute heart attack (myocardial infarction), on the other hand, showed no significant connection with Alzheimer's in the study.

Study Design and Diseases Investigated

The finding for low blood pressure, medically called hypotension, was surprisingly pronounced. This connection between cardiovascular diseases and Alzheimer's has so far been researched far less than that for high blood pressure. In the study, hypotension showed the strongest statistical association with Alzheimer's across both datasets: In the U.S. "All of Us" dataset, hypotension was associated with a 1.97-fold higher probability of an Alzheimer's diagnosis, and in the UK Biobank dataset with an even 2.74-fold higher probability.

The scientists emphasize that the study merely establishes a statistical connection, but does not prove causality. The diagnoses also come from medical records and not from individual blood pressure measurements. Medications that can lower blood pressure excessively include antihypertensives, diuretics, and certain heart medications.

A special form of hypotension is orthostatic hypotension: here, blood pressure drops significantly upon standing, which typically manifests through dizziness, lightheadedness, darkening of the visual field, and falls. Additional symptoms of problematically low blood pressure can include weakness, confusion, a tendency to faint, falls, and severe exhaustion.

Alongside the risk factors, the study also shows potential for prevention. First author Aili Toyli explained that the results underscored how important good cardiovascular health could be for the potential prevention of Alzheimer's. In a German-language statement, Toyli explained that the separate analysis of various heart diseases had made it possible to identify which adults with heart disease might have the highest risk for cognitive decline.

Findings on High Blood Pressure and Drops in Blood Pressure

Toyli also stressed that further research is needed to investigate the biological mechanisms behind the connection between cardiovascular diseases and Alzheimer's. Cholesterol plays a central role here: the body produces most of it itself in the liver. Cholesterol is essential for building cell membranes, the production of hormones and vitamin D, as well as for the formation of bile acids that help with fat digestion.

LDL transports cholesterol from the liver to the body's cells. Elevated LDL levels can deposit on the walls of blood vessels, narrow them, and increase the risk of arteriosclerosis, heart attack, and stroke. HDL, on the other hand, transports excess cholesterol back to the liver, where it is broken down. "Ein hoher HDL-Wert gilt deshalb als schützend."

Elevated cholesterol levels are among the most common risk factors for cardiovascular diseases. "Vor allem die Ernährung beeinflusst den LDL-Cholesterinspiegel maßgeblich." A genetic predisposition is often behind it, as the researchers point out. "Besonders bei familiär bedingten Fettstoffwechselstörungen reichen Ernährung und Bewegung häufig nicht aus."

Cholesterol, Diet, and Exercise

Hamburg cardiologist Jens von Beckerath primarily recommends a fiber-rich diet to people with elevated cholesterol levels. The European Society of Cardiology also points out that dietary fibers bind bile acids in the gut. Saturated fatty acids and trans fats increase LDL levels and can simultaneously lower protective HDL cholesterol. Polyunsaturated fatty acids, on the other hand, can help lower LDL levels while supporting HDL levels.

Avocados also show positive effects on LDL cholesterol and triglycerides in scientific studies. With the right selection of foods, blood lipid levels can in many cases be positively changed and the risk of heart attack or stroke lowered. Additionally: "Schon 150 Minuten moderate Bewegung pro Woche gelten als sinnvoll. Dazu zählen beispielsweise zügiges Gehen, Radfahren, Schwimmen oder leichtes Joggen." The Federal Office for Risk Assessment, however, points out that high-dose supplements can increase the risk of atrial fibrillation in people with existing heart disease.