Alzheimer’s disease is a progressive condition that develops as a person gets older rather than after reaching a specific age. Early detection remains crucial, and while this particular indicator may not be an early warning sign, disregarding it, as is common among many young people, may contribute to the onset of the disease.
A new study by UC Davis has found that having high blood pressure in your 30s can lead to worse brain health later in life, especially for men.
The study, published in JAMA Network Open, compared magnetic resonance imaging (MRI) brain scans of older adults who had high blood pressure in their 30s and 40s with those who had normal blood pressure.
The group with high blood pressure had lower regional brain volumes and worse white matter integrity, both of which are associated with dementia.
The study also revealed that negative brain changes in certain regions, such as reduced grey matter volume and frontal cortex volume, were more pronounced in men.
The researchers suggest that this difference may be due to the protective effects of estrogen prior to menopause.
Kristen M. George, the first author of the study and an assistant professor in the Department of Public Health Sciences, emphasized the importance of identifying modifiable risk and protective factors over the life course to reduce the burden of dementia.
“High blood pressure,” according to the author, “is an incredibly common and treatable risk factor associated with dementia.”
These findings show “hypertension status in early adulthood is important for brain health decades later.”
High blood pressure, or hypertension, is a condition where blood pressure levels are higher than what is considered normal. A blood pressure level less than 130/80 mmHg is considered normal.
According to estimates from the Centers for Disease Control and Prevention, nearly half of all adults in the United States, or 47%, have hypertension.
The prevalence of high blood pressure differs among different demographics, such as sex and race. Men are more likely to have hypertension than women, with about 50% of men having high blood pressure compared to 44% of women.
Hypertension rates also vary among different ethnic groups, with Black adults having the highest rate at approximately 56%, followed by white adults at 48%, Asian adults at 46%, and Hispanic adults at 39%.
Additionally, African Americans between the ages of 35-64 years are 50% more likely to develop high blood pressure than their white counterparts.
In the study, the researchers analyzed health data from a diverse group of older Asian, Black, Latino, and white adults, including 427 participants from the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) study and the Study of Healthy Aging in African Americans (STAR), spanning the period between 1964 to 1985.
By analyzing two blood pressure readings taken when the participants were between the ages of 30 and 40, the researchers were able to identify whether they had normal blood pressure, were transitioning to hypertensive, or were already hypertensive in young adulthood.
Using MRI scans conducted between 2017 and 2022, the researchers also searched for neuroimaging biomarkers of neurodegeneration and white matter integrity in the participants during their later years.
The study found that individuals with high blood pressure or transitioning to it have lower cerebral gray matter volume, frontal cortex volume, and fractional anisotropy, which is a measure of brain connectivity, compared to those with normal blood pressure.
Men with high blood pressure scored lower than women. These findings add to the growing body of evidence that cardiovascular risk factors in young adulthood can have a negative impact on brain health in later life, according to senior author Dr. Rachel Whitmer.
It is important to note that the sample size of the study did not allow for the examination of racial and ethnic differences, and caution is advised when interpreting results regarding sex differences. Additionally, the MRI data was only available from one-time point later in life, which limits the ability to determine specific evidence of neurodegeneration over time.
Rachel Whitmer, senior author of the study and a professor in the departments of Public Health Sciences and Neurology, as well as the chief of the Division of Epidemiology and associate director of the UC Davis Alzheimer’s Disease Center, emphasized the importance of early life risk factors in maintaining brain health in later life.
The study’s authors plan to continue following participants to gain further insights into the steps individuals can take in early life to promote healthy brain aging.
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