A new study has found that people who experience the early onset of hypertension are more likely to have smaller brains and more susceptible to developing dementia.
The research, published in the journal Hypertension, said increased efforts to reduce the appearance and progression of high blood pressure in young adults can make a world of difference later in life.
“Hypertension is very common in middle-aged people (45-64 years), and early onset high blood pressure is becoming more common,” said Mingguang He, senior author of the study and professor of ophthalmic epidemiology at the University of Melbourne in Australia. “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.”
Hypertension — or the long-term force of blood against artery walls — raises the risk of several serious conditions, including stroke, renal disease, ischaemic heart disease and other vascular diseases, despite being relatively easy and inexpensive to detect and treat. Decreasing the prevalence of high blood pressure, which has direct links to 8.5 million deaths per year worldwide, can reduce the number of yearly strokes by 35 to 40 per cent; heart attacks by 20 to 25 per cent; and cut the rate of heart failure in half, according to one study.
For the current study, researchers analyzed the randomized health data of 11,399 mostly Caucasian people with high blood pressure who were included in the UK Biobank and compared their MRI results to those of an equal number of participants — matched by age and health — without high blood pressure. Subjects, who were enrolled in the databank between 2006 and 2010, were divided into three groups: Those younger than 35; between the ages of 35 and 44; and between the ages of 45 and 54. MRIs were conducted between 2014 and 2019 and hypertension status was determined by doctor diagnosis.
In all three age groups analyzed by researchers, MRIs revealed that total brain volume was smaller among participants with hypertension, with people who were diagnosed with high blood pressure before the age of 35 experiencing the largest reduction. Among adults who exhibited normal blood pressure at the time of their MRI, those who were previously diagnosed with hypertension before the age of 35 had smaller total brain volume than those who had not.
“Individuals who had hypertension diagnosed at younger ages had smaller brain volumes on these one-time measurements,” said Xianwen Shang, lead author of the study and a research fellow at the Guangdong Provincial People’s Hospital in Guangzhou, China. “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.”
Investigators then matched 124,053 adults with high blood pressure to the same number of adults without hypertension and followed them for over a decade to determine the relationship, if any, to dementia. Over a period of up to 14 years, 4,626 were diagnosed with some form of dementia, with the risk significantly higher — 61 per cent — in those found to have had high blood pressure between the ages of 35 and 44.
The risk of developing vascular dementia — the second most common form of dementia behind Alzheimer’s disease — was 45 per cent higher in those diagnosed with high blood pressure between ages 45 to 54 and 69 per cent higher in those diagnosed between ages 35 to 44 compared to same-age adults without hypertension. The risk of vascular dementia was 80 per cent higher in those diagnosed with high blood pressure before the age of 35 but because these people were younger throughout the course of study, the relationship was not found to be significant as fewer cases of dementia had time to develop. No relationship was detected between hypertension and Alzheimer’s disease.
“Our 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,” Shang said. “The findings raise the possibility that better prevention and control of high blood pressure in early adulthood could help prevent dementia.”
Although the study was limited by a lack of diversity among its subject pool, the findings suggest that managing high blood pressure at a younger age may have a protective effect on brain health. “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,” He said.
Dave Yasvinski is a writer with Healthing.ca