Is It Difficult to Hear People When There Is Noise Around? A New Study Connects This to the Risk of Dementia
The ability to hear is one that the majority of us take for granted. However, new research suggests that adults should monitor their hearing for changes, as hearing impairments may be associated with the development of dementia as they age.
According to a research of over 80,000 persons over the age of 60, those who had difficulties hearing speech in noisy situations had a higher chance of dementia, a broad term for illnesses marked by memory loss and difficulty with language and other mental skills.
However, there is an upside: the study adds to the growing body of evidence demonstrating that hearing impairments are not just a symptom of dementia but also a risk factor for the disease, alerting individuals, their families, and physicians to its onset before any deterioration occurs.
“There has been a particular interest in hearing impairment and whether that can increase the risk of dementia,” explains epidemiologist and study author Thomas Littlejohns of the University of Oxford.
“Whilst preliminary, these results suggest speech-in-noise hearing impairment could represent a promising target for dementia prevention.”
Hearing loss was named as one of nine key, modifiable risk factors for dementia in 2017, alongside smoking and physical inactivity. In 2020, the seminal Lancet paper was amended to include three additional risk factors, bringing the total to 12.
The essential term here is modifiable: these risk factors are aspects of our lifestyle and general health that may be changed, so improving our overall health and decreasing our risk of developing health problems.
According to the Lancet reports, hearing loss may have the largest impact of all the 12 dementia risk factors — such that persons with untreated hearing loss in midlife are up to five times more likely to develop dementia.
To conduct additional research, the University of Oxford researchers used the UK Biobank, a research database established to elucidate the relationships between genetics, environmental variables, and health outcomes across a substantial proportion of the UK population.
The risk of developing dementia was measured in a cohort of over 82,000 women and men aged 60 years or older who were free of dementia and had their hearing assessed at the start of the trial.
The participants’ speech-in-noise hearing ability was assessed, which refers to their ability to distinguish snippets of speech in a noisy setting – in this case, identifying spoken numbers against a white background noise.
According to health records, 1,285 people acquired dementia after around 11 years.
“Participants who had worse hearing had almost double the risk of developing dementia compared to those who had good hearing,” Littlejohns explains.
Interestingly, about half of the participants in the study who had insufficient speech-in-noise hearing and around 42% of those who performed poorly on the test reported having no awareness of any hearing impairment.
The researchers also examined whether hearing impairments were associated with other established risk factors for dementia, such as social isolation and depression, both of which can occur when people have difficulty hearing.
“But we found little evidence that this was the case,” Littlejohns says.
To be certain, Littlejohns and his colleagues compared the data to determine whether or not people’s hearing performance had been damaged by underlying, undiscovered dementia — a process known as reverse causation.
However, when comparing trial participants who got dementia sooner (after 3 years) versus later (after 9 years), the risk of dementia remained nearly the same.
Although this is not the first study to discover a link between hearing loss and dementia, the researchers claim it is one of the first to examine dementia risk and people’s hearing capacity in noisy surroundings, which are more common in daily life.
Similarly extensive and large-scale investigations conducted in Australia and Taiwan have discovered that those who are hard of hearing are at an increased risk of dementia. However, these investigations relied on participant self-reports or on medical records indicating hearing loss.
“Large studies like the UK Biobank are powerful tools for identifying genetic, health and lifestyle factors linked to conditions like dementia,” said neuroscientist Katy Stubbs of Alzheimer’s Research UK, a research organization. “But it is always difficult to tease apart cause and effect in this type of research.”
Bear in mind that the most effective epidemiological research identify correlations between environmental factors, health, and disease at the population level.
“It’s important to bear in mind with this type of study design you can’t infer causality,” Littlejohns notes, “but this adds to the existing literature that hearing impairment could be a modifiable target to reduce the risk of developing dementia.”
Not to be forgotten, this research indicates that protecting our ears from hearing damage with earmuffs and earplugs, as well as assisting patients with hearing loss with hearing aids, may help decrease this potential risk factor for dementia, which affects millions worldwide.
Too few participants in this study were wearing hearing aids to draw any strong conclusions at the moment, and additional clinical trials will be required before we can say more. However, this is a novel area of research that may hold promise for our understanding and prevention of dementia.
The study appeared in Alzheimer’s & Dementia: The Alzheimer’s Association Journal.