People diagnosed with high blood pressure prior to 55 years old have smaller brain size and are more inclined to develop dementia compared with people with normal blood pressure, according to new research published today in Hypertension.
Data from the study indicates that initiating measures early on to control or delay high blood pressure may reduce the risk of dementia.
In the analysis, people who had high blood pressure between 35 and 44 years old had a 61% greater chance of developing dementia during the study’s follow-up period of eight to 10 years, compared to individuals who had normal blood pressure during the same time period.
“Hypertension is very common in middle-aged people (45-64 years), and early onset high blood pressure is becoming more common,” said Mingguang He, MD, PhD, senior author of the study and professor of ophthalmic epidemiology at the University of Melbourne in Australia, in a prepared statement. “Although the association among hypertension, brain health and dementia in later life has been well-established, it was unknown how age at onset of hypertension may affect this association. If this is proven, it would provide some important evidence to suggest earlier intervention to delay the onset of hypertension, which may, in turn, be beneficial in preventing dementia.”
The authors analyzed data from patients in the UK Biobank database that contained anonymous health information of about half a million volunteers between 2006 and 2010.
To assess brain changes, between 2014 and 2019, researchers compared MRI measurements of brain volume between two large groups of adults in the database: 11,399 people with high blood pressure diagnosed at different ages (younger than age 35; 35-44 years; and 45-54 years), and 11,399 participants who did not have high blood pressure.
The patients were matched for age and multiple health-related variables.
In the study, hypertension was defined as reporting a diagnosis of hypertension or inpatient records using the codes for international classification diseases.
From MRI scans, the researchers found:
- In each diagnostic age category (from 35 to 54), the total brain volume was smaller in people diagnosed with high blood pressure, and the brain volume of several regions were also smaller compared to the participants who did not have high blood pressure
- Hypertension diagnosed before age 35 was associated with the largest reductions in brain volume compared with controls
- Among people with normal blood pressure readings at the time of their MRI scans, those who were previously diagnosed with hypertension at <35 years old had smaller total brain volume compared to people with normal blood pressure who had never been diagnosed with hypertension.
To gauge dementia, the researchers analyzed how many patients developed dementia from any cause over a 11.9-year follow-up period.
In addition, they compared 124,053 people with high blood pressure and 124,053 matched adults who were not diagnosed with high blood pressure. During the follow-up period of up to 14 years; median of 11.9 years, 4,626 people developed some form of dementia, according to the authors.
The authors pointed out that, in contrast to vascular dementia, there was no relationship established between age at hypertension diagnosis and the risk of Alzheimer’s disease.
“Our study’s results provide evidence to suggest an early age at onset of hypertension is associated with the occurrence of dementia and, more importantly, this association is supported by structural changes in brain volume,” said Xianwen Shang, PhD, MPH, lead author of the study and a research fellow at the Guangdong Provincial People’s Hospital in China, in the same statement. “The findings raise the possibility that better prevention and control of high blood pressure in early adulthood could help prevent dementia.”
Read the full study here.