Genes linked to high blood pressure associated with lower Alzheimer’s risk

A new study has linked genetic variants which increase the risk of high blood pressure to a lower risk of Alzheimer’s disease. The research, which suggests a possible protective effect for treatments used to reduce blood pressure, was recently published in the June in the journal PLOS Medicine.
The study was led by an international team of researchers including scientists at Aarhus University in Denmark, the University of Cambridge and the University of Washington in the US. The team used a method called ‘Mendelian randomisation’, which uses genetics to investigate potential risk factors for disease, to study different factors that have previously been linked to an increase risk of Alzheimer’s disease.
A number of different observational studies have linked several factors – such as high blood pressure, type 2 diabetes and raised cholesterol – to an increased risk of Alzheimer’s. However, these studies have not been able to show for certain whether any of these factors might play a role in causing the disease. To investigate this further, the researchers investigated genetic variants that are known to affect the risk of some of these factors, to see whether they were also linked to a higher risk of Alzheimer’s.
The team looked at data from over 54,000 people who were part of the International Genomics of Alzheimer’s Project – 17,008 people with Alzheimer’s disease and 37,154 older people without the disease. In their analysis, they looked at genes that have previously been linked to several factors that are thought to affect the risk of Alzheimer’s, including type 2 diabetes, body mass index, cholesterol, and blood pressure.
Their results showed that people who carried certain genetic variants were less likely to develop Alzheimer’s disease compared to other people in the group. In particular, 24 different genetic variants which have previously been linked to an increased risk of high systolic blood pressure, were associated with a lower risk of Alzheimer’s disease. The researchers suggest that further investigation is needed to understand why these people may have lower Alzheimer’s risk, and point out that people who carry these genes are more likely to be prescribed anti-hypertensive drugs to reduce blood pressure. They suggest that future research should investigate whether anti-hypertensives may have any effect on reducing the risk of Alzheimer’s disease.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“A person’s risk of developing Alzheimer’s disease is likely to be influenced by a mix of genetic and lifestyle factors, many of which are not yet fully understood, and this valuable study underlines the complexity. This type of research can help to gain a better understanding of disease risk, but while these are useful results they do not show that having high blood pressure will prevent Alzheimer’s. Other studies have linked high blood pressure to an increased risk of Alzheimer’s, and there are many other known health risks associated with raised blood pressure, so people shouldn’t see this as a sign to abandon a healthy lifestyle.
“These results raise the possibility that anti-hypertensive treatments commonly used in this group of people may help protect against Alzheimer’s risk, and it would be important to see studies investigate this further. Investment in research is crucial to successfully fight the disease and find ways to prevent it, but in the meantime there are measures people can take to lower their risk. Current evidence suggests that eating a balanced diet, exercising regularly, not smoking, and keeping weight in check can all help to reduce the risk of Alzheimer’s.” (Science News)