A recent study led by Emily Ishak from Columbia University Irving Medical Center, published in JAMA Otolaryngology-Head & Neck Surgery, reveals a strong link between audiometry-measured hearing loss and dementia.

The research indicates that hearing loss in older adults accounts for up to 32% of new dementia cases over an eight-year period, a figure significantly higher than previous estimates.

Notably, dementia cases attributed to hearing loss were more common among adults aged 75 and older, with a population attributable fraction (PAF) of 31%, compared to 22% in younger individuals.

The study also found that women experienced a higher PAF at 31% compared to 24% for men, and White participants had a PAF of 28% versus 23% for Black participants.

Interestingly, the PAF estimates for incident dementia were consistent across different levels of hearing loss severity, with 16.2% for mild and 16.6% for moderate or greater hearing loss.

The study involved nearly 3,000 participants from the ARIC Neurocognitive Study, with a mean age of 75, where 66% had audiometric hearing loss, contrasting sharply with only 37% who self-reported hearing loss.

Hearing loss was measured both objectively through pure tone audiometry and subjectively via self-reports, defining audiometric hearing loss as a pure tone average of 26 dB or greater in the better-hearing ear.

Interestingly, self-reported hearing loss did not correlate with a significant increase in dementia risk, highlighting the importance of objective measurement.

However, the study faced limitations, including a lack of generalizability due to its focus on self-identified Black and White adults and potential biases in dementia classification.

The researchers advocate for public health interventions targeting significant audiometric hearing loss, suggesting that addressing this issue could potentially delay the onset of dementia in older adults.

Past studies had estimated the contribution of hearing loss to dementia cases to be between 2% and 19%, making this new finding particularly striking.