There is no strong evidence that hearing loss causes Alzheimer’s disease, according to new Queensland University of Technology (QUT) research.
The relationship between hearing loss and Alzheimer’s disease has long been debated, with some research suggesting mild hearing loss doubles a person’s risk of dementia. While other research proposes that people with severe hearing impairment are five times as likely to develop dementia.
In Australia, around 3.6 million people suffer from hearing loss, including one in three people over the age of 50. This number rises to one in two after the age of 60.
The QUT research found no genetic evidence that hearing loss causes Alzheimer’s disease, despite both conditions sharing a significant number of genetic variants.
Senior author and researcher in QIMR Berghofer’s Genetic Epidemiology Research Group Associate Professor Michelle Lupton said: “We did not find any genetic evidence however that one of the conditions caused the other. The lack of genetic evidence sheds doubt on whether the treatment for hearing impairment would change a person’s chances of developing Alzheimer’s disease in the future.
“Most of the 25 per cent of genetic variants that were common in both conditions were also associated with inflammation and the body’s immune response. This supports the mounting evidence of the importance of inflammation in Alzheimer’s disease.
“It’s possible that the relationship between these two traits may be due to a common cause that hasn’t been identified as yet.”
The study looked at the DNA of over 250,000 people with self-reported hearing loss and looked for an overlap in the genetic variants of people who had been diagnosed with Alzheimer’s disease, making it one of the largest studies of its kind.
Researchers said that the next steps will be to investigate even larger sample sizes and test whether specific clinically diagnosed forms of hearing loss or different ages of onset could have a causal role in Alzheimer’s disease.
“It is important that patients are always treated for their hearing loss to maintain quality of life, but this study also importantly provides new information on Alzheimer’s disease and indicates that treating hearing loss may not prevent the degenerative illness,” said Lupton.Do you have an idea for a story?
Email [email protected]