New research has highlighted a simple but effective way of reducing the risk of developing dementia.
The global study of over 28,000 people, published 26 October 2022 in the European Heart Journal, has provided the strongest evidence to date that lowering blood pressure in later life can cut the risk of dementia.
Dr Ruth Peters, Associate Professor at UNSW Sydney, and Program Lead for Dementia in The George Institute’s Global Brain Health Initiative, said that in the absence of significant dementia treatment breakthroughs, reducing the risk of developing the disease would be a welcome step forward.
“Given population ageing and the substantial costs of caring for people with dementia, even a small reduction could have considerable global impact,” she said.
“Our study suggests that using readily available treatments to lower blood pressure is currently one of our ‘best bets’ to tackle this insidious disease.”
She explained that while many trials have looked at the health benefits of lowering blood pressure, not many included dementia outcomes and even fewer were placebo-controlled – methodologically considered to provide the best level of evidence.
“Most trials were stopped early because of the significant impact of blood pressure lowering on cardiovascular events, which tend to occur earlier than signs of dementia,” Dr Peters said.
To examine the relationship between blood pressure and dementia more closely, researchers analysed five double-blind placebo-controlled randomised trials that used different blood pressure lowering treatments and followed patients until the development of dementia.
A total of 28,008 individuals with an average age of 69 and a history of high blood pressure from 20 countries were included. Across these studies, the mid-range of follow up was just over four years.
“We found there was a significant effect of treatment in lowering the odds of dementia associated with a sustained reduction in blood pressure in this older population,” Dr Peters said.
“Our results imply a broadly linear relationship between blood pressure reduction and lower risk of dementia, regardless of which type of treatment was used.”
Researchers hope the results will help in designing public health measures to slow the advance of dementia as well as informing treatment, where there may be hesitations around how far to lower blood pressure in older age.
“Our study provides the highest grade of available evidence to show that blood pressure lowering treatment over several years reduces the risk of dementia, and we did not see any evidence of harm,” Dr Peters said.
“But what we still don’t know is whether additional blood pressure lowering in people who already have it well-controlled or starting treatment earlier in life would reduce the long-term risk of dementia,” she added.
Dementia is fast becoming a global epidemic, currently affecting an estimated 50 million people worldwide – a number which is projected to triple by 2050, driven by aging populations in developed nations.
Dementia Australia Executive Director of Services Leanne Emerson said that the updated Causes of Death 2022 data, which has just been released by the ABS, showed that dementia was the leading cause of death for women and the second leading cause of death of all Australians.
“There are up to 487,500 Australians living with dementia in 2022. Without a medical breakthrough, the number of people with dementia is expected to increase to almost 1.1 million by 2058,” Ms Emerson said.
“Dementia is the chronic disease of the 21st century and this updated data reinforces the need for major investment in dementia research, services and support, as well as the importance of continuing to educate the community and raise awareness about dementia.”
According to the data, rate difference between ischaemic heart diseases and dementia continues to narrow – in 2017 the mortality rate of ischaemic heart disease was approximately 38 per cent higher than deaths due to dementia which in 2021 reduced to 9 per cent higher.
“If this data trend continues, it is likely that dementia will devastatingly become the leading cause of death of all Australians – dementia is first and foremost a health issue and must be a health and ageing policy priority for all governments, health services and the aged care sector,” she said.