New research from the UNSW’s Centre for Healthy Brain Ageing (CHeBA) in Sydney has highlighted the importance of addressing high blood pressure, and the role treating hypertension plays in decreasing the risk of developing Alzheimer's later in life.
Hypertension, or an average blood pressure above healthy ranges, is the most common risk factor for dementia.
It affects 1.3 billion globally, including more than half of all people above the age of 65.
The CHeBA’s research reveals those with untreated hypertension over the age of 60 have a 42% higher risk of developing Alzheimer’s dementia compared to those who are receiving treatment for their high blood pressure.
“Over the next 30 years the number of people living with Alzheimer’s disease around the world is likely to more than double to over 130 million people,” CHeBA Professor Perminder Sachdev said.
“Hypertension, a common contributor for dementia, may be undiagnosed in over two-thirds of patients with the disease.
“Treating this often silent but deadly illness will be crucial in tackling the pressing crisis we are seeing with increasing rates of dementia,” says Professor Sachdev.
Preventing Alzheimer's with focus on blood pressure
“Previous trials and longitudinal studies have indicated that ongoing antihypertensive use in late life reduces dementia risk but the specific impact on Alzheimer’s disease and non-Alzheimer’s disease risk remained unclear,” CHeBA research lead Dr Matthew Lennon said.
“In our new study, we found that those with untreated hypertension over the age of 60 had a 42% greater risk of developing Alzheimer’s dementia compared to those with treated hypertension.
“However, if you had a diagnosis of hypertension and were receiving treatment, your risk for Alzheimer’s dementia was no different from those without hypertension.
“The findings of this study suggest that antihypertensive use should be part of any Alzheimer’s disease prevention strategy throughout later life.”
Alzheimer's is a devastating neurological disease and the most common form of dementia.
Symptoms include impaired memory and judgement and altered emotions and behaviours, deteriorating over time as the damage to neurons in the brain accumulates.
We don’t currently understand what causes Alzheimer's, but we’ve identified risk factors, including physical inactivity, lack of mental exercise, smoking, obesity, diabetes, high cholesterol and high blood pressure.
There are currently about 400,000 people living with dementia in Australia, affecting as many as 1 in 10 Australians over the age of 65.
Long-term protective effect
The CHeBA found no significant differences in the protective effect offered by blood pressure treatments in men or women, nor among different ethnic backgrounds or as participants aged.
“This is an important result as studies often have difficulty including participants over the age of 80,” Dr Lennon explained.
“Our study, incorporating a collaboration of researchers from all around the world and a large number of older participants, indicates that even as people enter their 80s there are still associations between antihypertensive use and reduced risk of Alzheimer’s disease.
“Clinicians should consider this when balancing the risks and benefits of stopping medication in older patients.”
The research also offered a much broader cross-sectional approach than most, including populations in developing countries such as Nigeria and the Republic of Congo which are chronically underrepresented in medical research.