People with hearing loss are up to five times more likely to be affected by dementia than those without hearing loss. To try to understand this link, national charities Action on Hearing Loss and Alzheimer’s Research UK have teamed up to invest more than £150,000 into a research project conducted by researchers at the University of Manchester.
The investment is part of more than £300,000 committed by the two charities towards the research into the links between the two conditions.
In a study, published in the Lancet in 2017, unaddressed midlife hearing loss was predicted to be the highest contributing risk factor for developing dementia, potentially responsible for 9% of cases. Emerging evidence has shown that mild hearing loss is associated with a doubled risk of developing dementia, with moderate hearing loss linked to three times the risk, and severe hearing loss five times the risk.
To look into this further, one of the projects, supported by NIHR Manchester Biomedical Research Centre will look to establish if dementia is directly caused by hearing loss, if dementia is an indirect consequence of social isolation caused by hearing problems, or if hearing loss is a marker of biological factors that increase the risk of both hearing loss and dementia. The Manchester team will also investigate whether hearing aids can help reduce the risk of dementia.
Dr Piers Dawes, who will be leading the study, said:
“We know dementia is not an inevitable part of getting older but as the number of older people increases, more and more people are living with this condition.
“This is a global issue affecting 46.8 million people worldwide and therefore, there is an urgent need to find ways of preventing or delaying dementia. Several studies have reported that hearing loss in mid-life is associated with an increased risk of dementia in later life. But, they do not tell us whether hearing loss directly contributes to the risk, or if treating hearing loss, like with hearing aids, would help prevent this condition.
“Our research will help us understand why hearing loss is a marker of risk for dementia and assess the potential benefits of hearing aids in reducing the risk of developing this life affecting illness.”
Dr Ralph Holme of Action on Hearing Loss, said:
“Hearing loss and dementia can have devastating consequences, and with an ageing population it is an issue we can no longer ignore. We will also be funding research looking at whether inflammation is the link between hearing loss and dementia. We hope the research we are funding will ultimately lead to new treatments.”
Dr Sara Imarisio, Head of Research from Alzheimer’s Research UK said:
“Hearing loss affects over two thirds of people over the age of 65 and the fact that hearing loss is so common means that it could have a large impact on the overall number of people developing dementia across the population.
“By working in partnership with Action on Hearing Loss, this research funding will help improve our understanding of the underlying links between hearing loss and the development of dementia.
“With no treatments yet able to stop the progression of dementia, it is crucial that we continue to invest in research looking into ways we can reduce our risk of the condition.”
The two charities will be co-funding another £150,000 for a second project at the University of Western Ontario, Canada. This will explore if inflammation of nerve cells in the brain, following exposure to loud noise, speeds up cognitive decline. The research is one of the first studies into the biological processes that may link hearing loss and cognitive decline. Ultimately, it could lead to treatments that are able to reduce the risk of dementia associated with hearing loss.