High blood pressure, diabetes could slow thinking and memory in middle-aged people, raise dementia risk later
High blood pressure and diabetes appear to be doing more than just affecting heart health. These conditions can impact your mental abilities too. According to a new study, they change the structure of the brain, thereby lowering memory and thinking skills. If untreated, they could raise the risk of dementia in later life, researchers have warned.
"Monitoring and treating even modestly raised blood pressure might make a difference to the structure of the brain and speed of thinking in mid-life, while also offering the potential to reduce the risks of developing dementia later in life," said Masud Husain, Professor of Neurology and Cognitive Neuroscience at the Nuffield Department of Clinical Neurosciences and lead investigator of the study, in a statement.
The link between high blood pressure and diabetes and dementia is not new. The two conditions damage blood vessels that supply blood to the brain and are called cerebrovascular risk factors. While studies have shown that these conditions can raise the risk of the disease in later life, the new study highlights that effects on the speed of thinking and memory begin in mid-life.
To arrive at these findings, researchers analyzed the brain scans of 22,000 volunteers aged 44–73. Of them, 5% were battling diabetes, 21% were on cholesterol-lowering medication and 22% were on drugs to treat high blood pressure.
The MRI scans detected changes in the brain structure of people with high blood pressure and diabetes. They were changes in the brain's grey matter and the white matter connections, said Dr Michele Veldsman, Postdoctoral Research Scientist in Cognitive Neurology at the Department of Experimental Psychology and co-author of the study. Along with the scans, the participants took a test called a pair-matching game to assess their memory and speed.
After comparing results from scans and cognitive tests, researchers found a strong link between high blood pressure and lower mental abilities in people aged between 44-69. "For blood pressure, every mm of pressure in your arteries counts – even in people who aren’t on any treatment. For people who are on treatment, systolic blood pressures above 140 mm were associated with lower cognitive performance. The higher the pressure, the worse it is," said Husain. The team did not observe similar effects in people over 70.
However, these effects are unnoticeable. "The changes were subtle, and probably not something you would notice in day to day life," co-first author of the study, Oxford University neurologist Michele Veldsman told ScienceAlert. In 2017, nearly half a million deaths in the United States had links with high blood pressure, according to the Centers for Disease Control and Prevention (CDC). About 10.5% of Americans have diabetes.
The researchers said that doctors do not often treat mild blood pressure. "We can detect that even small increases in blood pressure have an impact on the brain right now. It is not surprising that if this is allowed to continue untreated for decades, it might have a cumulative impact on brain structure and function, eventually making it vulnerable to dementia,” Husain told The Guardian.
The study is published in Nature Communications.