Don't put the back of your ear wrong! Mayo study: hearing impairment is strongly associated with dementia progression, with a 95% increased risk!

Reduced communication skills and the increased cost of listening pose tangible safety concerns, while also putting patients at increased risk of social isolation, loneliness, depression, and cognitive decline
.
The association between hearing loss and dementia has received particular attention over the past decade and was identified as the largest potentially modifiable risk factor
for dementia development in the Lancet Commission reports in 2017 and 2020.
It is predicted that by 2050, nearly 2.
5 billion people worldwide will suffer from hearing loss
.

The small number of prospective studies, as well as large differences in hearing measurements and dementia assessments between studies, highlight the need
for more prospective longitudinal epidemiological data.
The study examined hearing loss and its potential link
to the development of mild cognitive impairment and dementia using formal behavioral pure tone and speech audiometry, conducted exclusively by audiologists by the Mayo Clinic Aging Study (MCSA).

MCSA is a population-based prospective study to investigate the incidence, prevalence, and risk factors
for mild cognitive impairment and dementia in Olmsted County, Minnesota, USA.
Participants undergo clinical examination
of neuropsychological tests at the time of registration and every 15 months.
Participants who participated in the study between November 29, 2004 and December 23, 2019 were aged 50 years or older and had undergone a formal behavioral audiometric assessment by an audiologist for hearing loss or as part of an annual comprehensive health assessment
.
The correlation between pure tone mean (PTA) and word recognition score (WRS) and dementia development was evaluated using Cox proportional risk regression with age as the time scale, and the correlation
of cognitive test scores over time was evaluated by linear mixed-effects model.

Of the 1200 eligible participants, the mean age at enrollment was 79 years (SD 9), 593 (49%) were male, and 207 developed dementia
during a follow-up period of an average of 7.
0 years (SD 3.
7).
。 After adjusting for sex, years of schooling, smoking status, diabetes, hypertension, apolipoprotein Eε4 carryover, and hearing rehabilitation (defined as hearing aid or cochlear implant use), PTA (risk ratio [HR] per 10 dB of increased hearing level was 0.
99 (95% CI 0.
89–1.
12; p=0.
91) and WRS (HR 0.
98 for every 10% reduction, 95% CI 0.
89 to 1.
07; P = 0·65) was significantly associated
with the occurrence of dementia.
However, over time, both PTA and WRS were significantly associated with poorer performance on cognitive tests: participants with PTAs above 25 decibels of hearing or WRS below 100 percent experienced significantly more severe declines in cognitive test scores
.
Information-based hearing impairment as assessed by participants' study partners was significantly associated with the development of dementia (HR 1.
95, 95% CI 1.
45-2.
62; p<0.
0001).

In this prospective population-based study, hearing difficulties based on subjective information were associated with the development of dementia, while objective measures of formal behavioral audiometry could predict poorer performance on cognitive tests over time, but not the progression
of dementia.
Other factors associated with central processing may enhance the effects
of peripheral hearing loss detected on behavioral hearing testing.

Original source:

John P Marinelli, et al.
Association between hearing loss and development of dementia using formal behavioural audiometric testing within the Mayo Clinic Study of Aging (MCSA): a prospective population-based study.
Lancet Healthy Longev 2022 Published Online November 18, 2022 https://doi.
org/10.
1016/ S2666-7568(22)00241-0 See Online/Comment https://doi.
org/10.
1016/ S2666-7568(22)00252-5