The 2024 update of the Lancet Commission on dementia provides new hopeful evidence about dementia prevention, intervention, and care. As people live longer, the number of people who live with dementia continues to rise, even as the age-specific incidence decreases in high-income countries, emphasising the need to identify and implement prevention approaches. We have summarised the new research since the 2020 report of the Lancet Commission on dementia, prioritising systematic reviews and meta-analyses and triangulating findings from different studies showing how cognitive and physical reserve develop across the life course and how reducing vascular damage (eg, by reducing smoking and treating high blood pressure) is likely to have contributed to a reduction in age-related dementia incidence. Evidence is increasing and is now stronger than before that tackling the many risk factors for dementia that we modelled previously (ie, less education, hearing loss, hypertension, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption [ie, >21 UK units, equivalent to >12 US units], traumatic brain injury [TBI], air pollution, and social isolation) reduces the risk of developing dementia. In this report, we add the new compelling evidence that untreated vision loss and high LDL cholesterol are risk factors for dementia.
We comprehensively summarized the cohort evidence to date on adult-onset hearing loss as risk factor for incident cognitive impairment and dementia, and examined the evidence for dose-response, risk for various dementia subtypes, and other moderators. Previous meta-analyses were less comprehensive. We included cohort studies with participants without dementia and with hearing assessments at baseline, minimum 2 years follow-up and incident cognitive outcomes. We identified fifty studies (N=1,548,754). Cohort studies consistently support that adult-onset hearing loss increases the risk of incident cognitive decline, dementia, MCI, and ADD.
Although a causal association remains to be determined, epidemiologic evidence suggests an association between hearing loss and increased risk of dementia. If we determine the association is causal, opportunity for targeted intervention for hearing loss may play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause).
More recently, hearing loss has been shown as a marker of risk for dementia. However, it is not known whether this association represents a causal impact of hearing loss, nor whether treating hearing loss may help prevent dementia. Most studies on relationships between hearing loss and cognitive outcomes are observational, are at risk of confounding, and cannot reach conclusions about causation. Encouraging policymakers, patients, and other health care practitioners to address hearing loss in terms of dementia prevention may be inappropriate on the grounds of both relevance at individual level and lack of clear evidence of benefit. We suggest that treating hearing loss may have important benefits in preventing or delaying diagnosis of dementia via improving orientation and functioning in daily life, without changing the underlying pathology. Rather than linking hearing loss to dementia risk, we suggest a positive message focusing on the known benefits of addressing hearing loss in terms of improved communication, quality of life, and healthy aging.
Hearing loss is independently associated with incident all-cause dementia. Whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study.
Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults. Further studies investigating the mechanistic basis of this association and whether hearing rehabilitative interventions could affect cognitive decline are needed.
Adjusting for numerous confounders, an increased risk of disability and dementia was found for participants reporting hearing problems. An increased risk of depression was found in men reporting hearing problems. In additional exploratory analyses, such associations were not found in those participants using hearing aids. Mortality was not associated with self-reported hearing loss. Our study confirms the strong link between hearing status and the risk of disability, dementia, and depression. These results highlight the importance of assessing the consequences of treating hearing loss in elders in further studies.
This data provides a large-scale longitudinal analysis on the association between hearing loss and cognition, supporting the hypothesis that use of hearing aids maintains cognitive function over time. This warrants further exploration as an easily modifiable risk factor for cognitive impairment in older adults.
An independent association was observed between cognition and subclinical HL. The association between hearing and cognition may be present earlier in HL than previously understood. Studies investigating whether treating HL can prevent impaired cognition and dementia should consider a lower threshold for defining HL than the current 25-dB threshold.
Identifies hearing impairment as the biggest potentially modifiable risk factor for dementia, accounting for 8%. Use of hearing aids for hearing loss is and reduce hearing loss by protection of ears from excessive noise exposure is encouraged in dementia prevention strategies as ways of maintaining or increasing cognitive reserve.
MCI participants that used hearing aids were at significantly lower risk of developing all-cause dementia compared to those not using hearing aids (P = 0.004). Among hearing-impaired adults, hearing aid use was independently associated with reduced dementia risk. The causality between hearing aid use and incident dementia should be further tested.
Hearing impairment was associated with increased risk of MCI and an accelerated rate of cognitive decline (P < .001). Hearing aid users were less likely to develop MCI than hearing-impaired individuals who did not use a hearing aid (P = .001). No difference in risk of MCI was observed between individuals with normal hearing and hearing-impaired adults using hearing aids (P = .51). Use of hearing aids may help mitigate cognitive decline associated with hearing loss.
The findings from this report suggest that the timely identification of hearing loss and subsequent acquisition of hearing aids may be important considerations for reducing declines in cognitive function that manifests differently in U.S. population subgroups.
The hearing intervention did not reduce 3-year cognitive decline in the primary analysis of the total cohort. However, a prespecified sensitivity analysis showed that the effect differed between the two study populations that comprised the cohort. In the ARIC cohort, the hearing intervention was associated with a 48% reduction in 3-year cognitive change compared with in the health education control group. These findings suggest that a hearing intervention might reduce cognitive change over 3 years in populations of older adults at increased risk for cognitive decline but not in populations at decreased risk for cognitive decline.
The results of this cohort study suggest that hearing loss was associated with increased dementia risk, especially among people not using hearing aids, suggesting that hearing aids might prevent or delay the onset and progression of dementia. The risk estimates were lower than in previous studies, highlighting the need for more high-quality longitudinal studies.
Regular hearing aid use was associated with lower risks of mortality than in never users in US adults with hearing loss when accounting for age, hearing loss, and other potential confounders. Future research is needed to investigate the potential protective role of hearing aid use against mortality for adults with hearing loss.
Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission
The 2024 update of the Lancet Commission on dementia provides new hopeful evidence about dementia prevention, intervention, and care. As people live longer, the number of people who live with dementia continues to rise, even as the age-specific incidence decreases in high-income countries, emphasising the need to identify and implement prevention approaches. We have summarised the new research since the 2020 report of the Lancet Commission on dementia, prioritising systematic reviews and meta-analyses and triangulating findings from different studies showing how cognitive and physical reserve develop across the life course and how reducing vascular damage (eg, by reducing smoking and treating high blood pressure) is likely to have contributed to a reduction in age-related dementia incidence. Evidence is increasing and is now stronger than before that tackling the many risk factors for dementia that we modelled previously (ie, less education, hearing loss, hypertension, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption [ie, >21 UK units, equivalent to >12 US units], traumatic brain injury [TBI], air pollution, and social isolation) reduces the risk of developing dementia. In this report, we add the new compelling evidence that untreated vision loss and high LDL cholesterol are risk factors for dementia.
July 2024
Adult-onset hearing loss and incident cognitive impairment and dementia – A systematic review and meta-analysis of cohort studies
We comprehensively summarized the cohort evidence to date on adult-onset hearing loss as risk factor for incident cognitive impairment and dementia, and examined the evidence for dose-response, risk for various dementia subtypes, and other moderators. Previous meta-analyses were less comprehensive. We included cohort studies with participants without dementia and with hearing assessments at baseline, minimum 2 years follow-up and incident cognitive outcomes. We identified fifty studies (N=1,548,754). Cohort studies consistently support that adult-onset hearing loss increases the risk of incident cognitive decline, dementia, MCI, and ADD.
May 2024
Hearing Loss and Dementia: Where to From Here?
More recently, hearing loss has been shown as a marker of risk for dementia. However, it is not known whether this association represents a causal impact of hearing loss, nor whether treating hearing loss may help prevent dementia. Most studies on relationships between hearing loss and cognitive outcomes are observational, are at risk of confounding, and cannot reach conclusions about causation. Encouraging policymakers, patients, and other health care practitioners to address hearing loss in terms of dementia prevention may be inappropriate on the grounds of both relevance at individual level and lack of clear evidence of benefit. We suggest that treating hearing loss may have important benefits in preventing or delaying diagnosis of dementia via improving orientation and functioning in daily life, without changing the underlying pathology. Rather than linking hearing loss to dementia risk, we suggest a positive message focusing on the known benefits of addressing hearing loss in terms of improved communication, quality of life, and healthy aging.
May 2024
Association between hearing aid use and mortality in adults with hearing loss in the USA: a mortality follow-up study of a cross-sectional cohort
Regular hearing aid use was associated with lower risks of mortality than in never users in US adults with hearing loss when accounting for age, hearing loss, and other potential confounders. Future research is needed to investigate the potential protective role of hearing aid use against mortality for adults with hearing loss.
January 2024
Hearing Loss, Hearing Aid Use, and Risk of Dementia in Older Adults
The results of this cohort study suggest that hearing loss was associated with increased dementia risk, especially among people not using hearing aids, suggesting that hearing aids might prevent or delay the onset and progression of dementia. The risk estimates were lower than in previous studies, highlighting the need for more high-quality longitudinal studies.
January 2024
Hearing intervention versus health education control to reduce cognitive decline in older adults with hearing loss in the USA (ACHIEVE): a multicentre, randomised controlled trial
The hearing intervention did not reduce 3-year cognitive decline in the primary analysis of the total cohort. However, a prespecified sensitivity analysis showed that the effect differed between the two study populations that comprised the cohort. In the ARIC cohort, the hearing intervention was associated with a 48% reduction in 3-year cognitive change compared with in the health education control group. These findings suggest that a hearing intervention might reduce cognitive change over 3 years in populations of older adults at increased risk for cognitive decline but not in populations at decreased risk for cognitive decline.
July 2023
Self-reported hearing loss, hearing aid use, and cognitive function among U.S. older adults
The findings from this report suggest that the timely identification of hearing loss and subsequent acquisition of hearing aids may be important considerations for reducing declines in cognitive function that manifests differently in U.S. population subgroups.
June 2022
The impact of hearing impairment and hearing aid use on progression to mild cognitive impairment in cognitively healthy adults: An observational cohort study
Hearing impairment was associated with increased risk of MCI and an accelerated rate of cognitive decline (P < .001). Hearing aid users were less likely to develop MCI than hearing-impaired individuals who did not use a hearing aid (P = .001). No difference in risk of MCI was observed between individuals with normal hearing and hearing-impaired adults using hearing aids (P = .51). Use of hearing aids may help mitigate cognitive decline associated with hearing loss.
February 2022
Hearing Loss and Cognition: What We Know and Where We Need to Go
Although a causal association remains to be determined, epidemiologic evidence suggests an association between hearing loss and increased risk of dementia. If we determine the association is causal, opportunity for targeted intervention for hearing loss may play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause).
February 2022
Association of the use of hearing aids with the conversion from mild cognitive impairment to dementia and progression of dementia: A longitudinal retrospective study
MCI participants that used hearing aids were at significantly lower risk of developing all-cause dementia compared to those not using hearing aids (P = 0.004). Among hearing-impaired adults, hearing aid use was independently associated with reduced dementia risk. The causality between hearing aid use and incident dementia should be further tested.
February 2021
Dementia prevention, intervention, and care: 2020 report of the Lancet Commission
Identifies hearing impairment as the biggest potentially modifiable risk factor for dementia, accounting for 8%. Use of hearing aids for hearing loss is and reduce hearing loss by protection of ears from excessive noise exposure is encouraged in dementia prevention strategies as ways of maintaining or increasing cognitive reserve.
August 2020
Use Of Hearing Aids In Older Adults With Hearing Loss Is Associated With Improved Cognitive Trajectory
This data provides a large-scale longitudinal analysis on the association between hearing loss and cognition, supporting the hypothesis that use of hearing aids maintains cognitive function over time. This warrants further exploration as an easily modifiable risk factor for cognitive impairment in older adults.
January 2020
Death, Depression, Disability, and Dementia Associated With Self-reported Hearing Problems: A 25-Year Study
Adjusting for numerous confounders, an increased risk of disability and dementia was found for participants reporting hearing problems. An increased risk of depression was found in men reporting hearing problems. In additional exploratory analyses, such associations were not found in those participants using hearing aids. Mortality was not associated with self-reported hearing loss. Our study confirms the strong link between hearing status and the risk of disability, dementia, and depression. These results highlight the importance of assessing the consequences of treating hearing loss in elders in further studies.
September 2018
Hearing Loss and Cognitive Decline Among Older Adults
Hearing loss is independently associated with accelerated cognitive decline and incident cognitive impairment in community-dwelling older adults. Further studies investigating the mechanistic basis of this association and whether hearing rehabilitative interventions could affect cognitive decline are needed.
December 2013
Hearing loss and incident dementia
Hearing loss is independently associated with incident all-cause dementia. Whether hearing loss is a marker for early-stage dementia or is actually a modifiable risk factor for dementia deserves further study.
February 2011
Association of Subclinical Hearing Loss With Cognitive Performance
An independent association was observed between cognition and subclinical HL. The association between hearing and cognition may be present earlier in HL than previously understood. Studies investigating whether treating HL can prevent impaired cognition and dementia should consider a lower threshold for defining HL than the current 25-dB threshold.
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