DALLAS, Oct. 4, 2021 — Individuals who are diagnosed with high blood pressure at ages 35-44 had smaller brain size and were more likely to develop dementia compared to people who had normal blood pressure, according to new research published today in Hypertension , an American Heart Association journal.
The results raise the possibility that taking steps in young adulthood to control or delay the onset of high blood pressure may reduce the risk of dementia.
“Hypertension is very common in middle-aged people (45-64 years), and early onset high blood pressure is becoming more common. 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,” said Mingguang He, M.D., Ph.D., senior author of the study and professor of ophthalmic epidemiology at the University of Melbourne in Melbourne, Australia.
The researchers analyzed data from participants in the UK Biobank, a large database containing detailed anonymous health information of about half a million volunteer participants in the United Kingdom. To determine brain changes, they compared magnetic resonance imaging (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, matched for age and multiple health-related variables. Participants entered the databank between 2006 and 2010, and they had MRI brain scans between 2014 and 2019. Hypertension in this study was defined as reporting a diagnosis of hypertension (told by a doctor) or inpatient records using the codes for international classification diseases. The blood pressure reading at the time of their MRI scans was controlled in the analysis.
From the MRI scans, the investigators found:
“Individuals who had hypertension diagnosed at younger ages had smaller brain volumes on these one-time measurements. Future research with brain volumes measured at multiple time points could confirm whether hypertension diagnosed at a younger age is associated with a greater decrease in brain volume over time,” said Xianwen Shang, Ph.D., M.P.H., lead author of the study and a research fellow at the Guangdong Provincial People’s Hospital in Guangzhou, China.
To evaluate dementia, the investigators examined how many participants developed dementia from any cause over a 11.9-year follow-up period, comparing 124,053 people with high blood pressure and 124,053 matched adults who did not have high blood pressure. During the follow-up period (up to 14 years; median of 11.9 years), 4,626 people developed some form of dementia. Analyzing the occurrence of dementia in relation to blood pressure diagnosis, the researchers found:
“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 Shang. The findings raise the possibility that better prevention and control of high blood pressure in early adulthood could help prevent dementia.
“An active screening program to identify individuals with early hypertension and provide earlier, intensive high blood pressure treatment might help reduce the risk of developing dementia in the future,” said He.
In future research, the investigators are planning to examine medical records to detect whether the onset of dementia was preceded by other medical conditions with previously established connections to dementia risk, such as diabetes or stroke, in people who developed high blood pressure during young adulthood or middle age. Results from this study of a predominantly Caucasian population are not necessarily generalizable to people from other racial or ethnic groups.
Co-authors are Edward Hill, Ph.D.; Zhuoting Zhu, M.D., PhD.; Jiahao Liu, B.Sc.; Zongyuan Ge, Ph.D.; and Wei Wang, M.D., Ph.D. Authors’ disclosures are listed in the manuscript.
The study was funded by the Fundamental Research Funds of the State Key Laboratory of Ophthalmology, Project of Investigation of Health Status of Employees of Financial Industry in Guangzhou, China; and the Science and Technology Program of Guangzhou, China.
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10.1161/HYPERTENSIONAHA.121.17608
The Association of Age at Diagnosis of Hypertension With Brain Structure and Incident Dementia in the UK Biobank
4-Oct-2021