Informant-based hearing difficulties and the risk for mild cognitive impairment and dementia

A comprehensive evaluation on the associations between hearing and vision impairments and risk of all-cause and cause-specific dementia: results from cohort study, meta-analysis and Mendelian randomization study

BACKGROUND

Epidemiological studies show inconsistent links between hearing/vision impairment and dementia risk. Using multisource data, we investigated how single or combined sensory impairments relate to risks of all-cause and specific types of dementia.

METHODS

We employed a triangulation approach combining three methodologies. We analyzed 90,893 UK Biobank (UKB) adults to explore single and joint effects of hearing and vision impairments on all-cause and Alzheimer's disease (AD), vascular dementia (VD) and non-AD non-VD (NAVD). A meta-analysis of prospective studies involving 937,908 participants provided stronger evidence. Finally, we conducted Mendelian randomization (MR) analysis using genome-wide association studies from UKB (361,194 participants) and FinnGen (412,181 participants) to validate relationships between sensory impairments and dementia occurrence.

RESULTS

In the UKB cohort study, compared to participants with normal hearing, those in the mild and severe hearing impairment groups had progressively and significantly higher risk of all-cause dementia (mild: HR1.52, 95%CI 1.31-1.77; severe: HR1.80, 95%CI 1.36-2.38), AD (mild: HR1.63, 95%CI 1.30-2.04; severe: HR2.18, 95%CI 1.45-3.27), VD (mild: HR1.68, 95%CI 1.19-2.37; severe: HR1.47, 95%CI 1.22-1.78), and NAVD (mild: HR1.47, 95%CI 1.22-1.78; severe: HR1.98, 95%CI 1.43-2.75). Besides, vision impairment was associated with an increased risk of all-cause dementia (HR1.55, 95%CI 1.18-2.04) and NAVD (HR1.51, 95%CI 1.07-2.13). Furthermore, dual sensory impairment was associated with stepwise increased risks of all-cause and cause-specific dementia than single hearing or vision impairment. In the meta-analysis of 31 prospective cohort studies, risks of all-cause dementia and AD were elevated in participants with single hearing impairment (all-cause dementia: HR1.30, 95%CI 1.21-1.40; AD: HR1.30, 95%CI 1.21-1.40) and dual sensory impairment (all-cause dementia: HR1.63, 95%CI1.14-2.12; AD: HR 2.55, 95%CI 1.19-3.91), while single vision impairment only associated with higher risk of all-cause dementia (HR1.43, 95%CI 1.16-1.71) but not AD. Finally, the MR analysis revealed a significant association between hearing impairment and all-cause dementia (OR1.74, 95%CI 1.01-2.99), AD (OR1.56, 95%CI 1.09-2.23), and NAVD (OR1.14, 1.02-1.26), as well as vision impairment and NAVD (OR1.62, 95%CI 1.13-2.33).

CONCLUSIONS

Our findings showed significant associations between hearing and vision impairments and increased risks of all-cause and cause-specific dementia. Standardized hearing and vision assessment and intervention should be emphasized in dementia prevention strategies.

Adult-onset hearing loss and incident cognitive impairment and dementia - A systematic review and meta-analysis of cohort studies

BACKGROUND

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.

METHODS

We included cohort studies with participants without dementia and with hearing assessments at baseline, minimum 2 years follow-up and incident cognitive outcomes. We used random-effect models and subgroup and meta-regression on moderator analyses.

RESULTS

We identified fifty studies (N=1,548,754). Hearing loss (yes/no) was associated with incident dementia risk (HR=1.35 [95% CI = 1.26 - 1.45), mild cognitive impairment (MCI HR=1.29 [95% CI = 1.11 - 1.50]), cognitive decline not specified as MCI or dementia (HR=1.29 [95% CI = 1.17 - 1.42]), and Alzheimer's disease dementia (ADD, HR=1.56 [95% CI = 1.30 - 1.87]), but not with vascular dementia (HR, 1.30 [95% CI = 0.83 - 2.05]). Each 10-decibel worsening of hearing was associated with a 16% increase in dementia risk (95% CI = 1.07 - 1.27). The effect of hearing loss did not vary across potential moderators.

CONCLUSIONS

Cohort studies consistently support that adult-onset hearing loss increases the risk of incident cognitive decline, dementia, MCI, and ADD.

Impact of hearing loss on cognitive function in community-dwelling older adults: serial mediation of self-rated health and depressive anxiety symptoms

Background

Hearing loss can exacerbate cognitive decline; therefore, exploring the mechanisms through which hearing loss affects cognitive function is crucial. The current study aimed to investigate the impact of hearing loss on cognitive function and the mediating role played by self-rated health and depressive anxiety symptoms.

Methods

Using stratified whole-group random sampling, the study employed a cross-sectional design and included 624 participants aged ≥65 years from three communities in Urumqi, China. Cognitive function was assessed using the Mini-Mental State Examination. Hearing function and self-rated health were determined by self-report. The 15-item Geriatric Depression Scale and the 7-item Generalized Anxiety Disorder Scale were used to assess depressive anxiety symptoms. Serial mediation analysis was performed using AMOS 26.0.

Results

Hearing loss can not only negatively affect cognitive function in older adults directly (direct effect = -0.106; SE = 0.045; 95% confidence interval (CI): -0.201 to -0.016), but also indirectly affect the relationship between hearing loss and cognitive function through self-rated health and depressive anxiety symptoms. The results of the serial mediation analysis showed that the total indirect effect of self-rated health and depressive anxiety symptoms was -0.115 (95% CI: -0.168 to -0.070), and the total effect of the model was -0.221 (95% CI: -0.307 to -0.132), with the total indirect effect accounting for 52.04% of the total effect of the model.

Conclusion

Our study discovered that there is a partial mediation of the relationship between hearing loss and cognitive function by self-rated health and depressive anxiety symptoms. It is suggested that by enhancing self-rated health and ensuring good mental health, the decline in cognitive function among older adults with hearing loss can be delayed.

Cognitive Performance, Sociodemographic Factors, Pure-Tone Audiometry, and their Association with Speech Discrimination: A Prospective Population-Based Study of 1,061 Older Adults

OBJECTIVE

Hearing loss is increasingly recognized as a chronic disease state with important health sequelae. Although considered a central component of routine audiometric testing, the degree to which various patient factors influence speech discrimination is poorly characterized to date. The primary objective of the current work was to describe associations of cognitive performance, sociodemographic factors, and pure-tone audiometry with speech discrimination in older adults.

STUDY DESIGN

Prospective study.

SETTING

Olmsted County, Minnesota.

PATIENTS

There were 1,061 study participants 50 years or older at enrollment in the population-based Mayo Clinic Study of Aging between November 2004 and December 2019 who underwent formal audiometric and cognitive testing included in the current investigation.

MAIN OUTCOME MEASURES

The primary outcome measure was word recognition scores (WRSs; measured as <100% vs 100% as well as continuous), with pure-tone averages (PTAs; 0.5, 1, 2, and 3 kHz), age, sex, years of education, state area deprivation index (ADI) quintiles, and global cognition z scores as explanatory features.

RESULTS

The mean (SD) age among the 1,061 participants was 76 (9) years with 528 (50%) males. Participant age [OR (95% CI) for a 10-year increase of 1.8 (1.4-2.3), p < 0.001], male sex [OR = 2.6 (1.9-3.7), p < 0.001], and PTA [OR for a 10-dB hearing loss increase of 2.4 (2.1-2.8), p < 0.001] were all significantly associated with <100% WRSs, with the greatest explanatory ability attributable to the PTA. Years of education ( p = 0.9), state ADI quintile ( p = 0.6), and global cognitive performance ( p = 0.2) were not associated with WRS. The multivariable model demonstrated strong predictive ability for less than perfect WRSs, with a c index of 0.854. Similar results were seen for WRSs analyzed as continuous, with the multivariable model resulting in an R2 value of 0.433.

CONCLUSIONS

Although PTA exhibited the greatest influence on speech discrimination, advancing age and male sex both independently increased the likelihood of having worse speech discrimination among older adults, even after accounting for years of education, neighborhood-level socioeconomic disadvantage, and cognitive function. These findings help identify patient factors that can be instrumental when designing screening programs for adult-onset hearing loss.

Validation of a tablet-based assessment of auditory sensitivity for researchers

Quantifying hearing acuity is increasingly important across a wide range of research areas in the behavioral and neurosciences. Scientists have relied on either self-reported hearing status or the availability of diagnostic hearing assessment in past studies. There remains a need for a valid and reliable assessment of auditory sensitivity that can provide estimates of the magnitude of hearing loss, if present, without requirements for professional audiologists, facilities, and equipment that are needed to conduct a diagnostic hearing assessment. The goal of this experiment was to validate the NIH Toolbox® Hearing Threshold Test (HTT), a tablet-based hearing assessment available via iPad application that uses consumer-grade headphones, on a clinical sample of children and adults with varying degrees of hearing acuity. Electroacoustic analysis of the hearing assessment application and headphones demonstrated acoustic outputs within established conformity standards for hearing assessment. Twenty-seven children and 63 adults participated in a standard diagnostic hearing assessment and the experimental tablet-based assessment. The results showed that thresholds from the tablet-based assessment were highly correlated with thresholds from the clinical hearing assessment (r = .83-.93) for children and adults for all frequencies and across a range of levels of hearing acuity. The HTT also met clinical test-retest reliability standards (Cronbach's α > .86). The tablet-based hearing assessment provides acceptable estimates of hearing levels for children and adults when diagnostic audiometric assessment capabilities are not available.

Hearing Loss and Cognitive Function in Early Old Age: Comparing Subjective and Objective Hearing Measures

INTRODUCTION

Population-based research has consistently shown that people with hearing loss are at greater risk of cognitive impairment. We aimed to explore the cross-sectional association of both subjective and objective hearing measures with global and domain-specific cognitive function. We also examined the influence of hearing aid use on the relationship.

METHODS

A population-based sample (n = 1,105, 52% women) of 70-year-olds that were representative of the inhabitants of the city of Gothenburg, Sweden completed a detailed cognitive examination, pure-tone audiometry, and a questionnaire regarding perceived hearing problems. A subsample (n = 247, 52% women) also completed a test of speech-recognition-in-noise (SPRIN). Multiple linear regression analyses were conducted to explore the association of hearing with cognitive function, adjusting for sex, education, cardiovascular factors, and tinnitus.

RESULTS

Global cognitive function was independently associated with the better ear pure-tone average across 0.5-4 kHz (PTA4, β = -0.13, 95% CI, -0.18, -0.07), the better ear SPRIN score (β = 0.30, 95% CI, 0.19, 0.40), but not with the self-reported hearing measure (β = -0.02, 95% CI, -0.07, 0.03). Both verbally loaded and nonverbally loaded tasks, testing a variety of cognitive domains, contributed to the association. Hearing aid users had better global cognitive function than nonusers with equivalent hearing ability. The difference was only significant in the mild hearing loss category.

DISCUSSION

In a population-based sample of 70-year-old persons without dementia, poorer hearing was associated with poorer global and domain-specific cognitive function, but only when hearing function was measured objectively and not when self-reported. The speech-in-noise measure showed the strongest association. This highlights the importance of including standardized hearing tests and controlling for hearing status in epidemiological geriatric research. More research is needed on the role that hearing aid use plays in relation to age-related cognitive declines.

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

BACKGROUND

Hearing loss has been identified as a potential major modifiable risk factor for developing dementia. This study examined associations between formal behavioural pure-tone and speech audiometry assessed by an audiologist with development of dementia in the Mayo Clinic Study of Aging (MCSA).

METHODS

The MCSA is a prospective population-based study examining the incidence, prevalence, and risk factors of mild cognitive impairment and dementia in Olmsted County, Minnesota, USA. Participants undergo clinical examinations with neuropsychological testing at enrolment and every 15 months. Participants were 50 years or older at enrolment between Nov 29, 2004, and Dec 23, 2019, who underwent formal behavioural audiometric evaluation by an audiologist due to concerns about hearing loss or as a part of annual comprehensive health assessments. Associations of pure-tone average (PTA) and word recognition scores (WRS) with the development of dementia were evaluated using Cox proportional hazards regression with age as the timescale, and associations with changes in cognitive testing scores over time were evaluated using linear mixed-effects models.

FINDINGS

Among 1200 eligible participants, the mean age at enrolment was 79 years (SD 9), 593 (49%) were men, and 207 developed dementia during a mean of 7·0 years (SD 3·7) of follow-up. After adjusting for sex, years of education, smoking status, diabetes, hypertension, apolipoprotein E ε4 carriership, and hearing rehabilitation (defined as hearing aid or cochlear implant use), neither PTA (hazard ratio [HR] per 10-decibels hearing level increase of 0·99 (95% CI 0·89-1·12; p=0·91) nor WRS (HR per 10% decrease of 0·98, 95% CI 0·89-1 ·07; p=0·65) was significantly associated with the development of dementia. However, both PTA and WRS were significantly associated with poorer performance in cognitive testing over time: participants with a PTA higher than 25 decibels hearing level or a WRS lower than 100% had significantly worse declines in cognitive testing scores. Informant-based hearing difficulties assessed by the participant's study partner were significantly associated with the development of dementia (HR 1·95, 95% CI 1·45-2·62; p<0·0001).

INTERPRETATION

In this prospective population-based study, subjective informant-based hearing difficulties were associated with development of dementia, whereas objective measures on formal behavioural audiometry were predictive of poorer performance on cognitive testing over time but not the development of dementia. Other factors related to central processing might potentiate the effects of peripheral hearing loss detected on behavioural audiometric testing.

FUNDING

National Institute of Health, the Alexander Family Alzheimer's Disease Research Professorship of the Mayo Clinic, the GHR Foundation, the Mayo Foundation for Medical Education and Research, the Liston Award, the Schuler Foundation, the Rochester Epidemiology Project medical records linkage system, and the National Institute on Aging.

Effect of hearing loss on cognitive function in patients with mild cognitive impairment: A prospective, randomized, and controlled study

Background

Hearing loss (HL) may increase the risk of cognitive decline in the elderly. However, the randomized controlled study on the effect of HL on cognitive function in mild cognitive impairment (MCI) is very limited.

Methods

From 1 November 2020 to 30 March 2022, 1,987 individuals aged 55–65 years were randomly divided into the MCI with hearing impairment (MCI-HI), MCI without HI (MCI-nHI), and no MCI (nMCI) groups by stratified sampling, with 30 participants in each group. The Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the pure tone audiometry (PTA), and the auditory brainstem response (ABR) were measured at baseline and a follow-up 12 months later. The trial protocol was registered with ClinicalTrials.gov with the registration number NCT05336942.

Results

Among the 90 participants, the average age was 60.41 ± 6.48 years. In the MCI-HI group at baseline, the PTA score of both the ears was negatively correlated with the naming and memory score (p < 0.05), and the PTA score of both the ears was negatively correlated with the MoCA and abstraction score at the 12-month follow-up (p < 0.05). However, there were no significant differences among the PTA, the ABR, the MMSE, and the MoCA scores in the MCI-nHI and nMCI groups (p > 0.05). Regression analysis showed that the PTA score of the right ear at baseline was an important factor associated with the MoCA, visuospatial/executive, naming, and abstraction scores at the 12-month follow-up (β = −0.776 to −0.422, p < 0.05).

Conclusion

HL was significantly negatively associated with cognitive function only in patients with MCI with hearing impairment (HI), and the PTA of the right ear may be a predictor of cognitive decline after 1 year in patients with MCI with HI. This information may help primary healthcare clinicians to prevent MCI by screening and intervening in care for elderly patients with HL.

Downregulation of REST in the cochlea contributes to age-related hearing loss via the p53 apoptosis pathway

Age-related hearing loss (AHL) is the most common sensory disorder amongst the elderly population. Although the degeneration of spiral ganglion neurons (SGNs) and hair cells (HCs) is considered to play a critical role in AHL, the mechanism has not been fully outlined. The repressor element 1-silencing transcription factor (REST) has recently been associated with mediating cell death in neurodegenerative diseases. However, whether REST induces degeneration of cochlear HCs and SGNs to contribute to AHL remains unknown. Here, we report that REST expression was decreased in HCs and SGNs in AHL mice. Conditional deletion of Rest in HCs and SGNs of 2-month-old mice resulted in hearing loss accompanied by the upregulation of p53, TNFR1(tumor necrosis factor receptor-1), and cleaved caspase-3. The p53 inhibitor pifithrin-α significantly attenuated SGN and HC damage and rescued hearing impairment in Rest cKO mice. Furthermore, downregulation of REST by H₂O₂ treatment induced apoptosis in the House Ear Institute Organ of Corti 1 cell, through the upregulation of p53. In contrast, overexpression of REST reversed the changes in p53 expression. In addition, REST was further shown to bind directly to the p53 promoter site, thereby inhibiting the effect of p53. Finally, in aged mice, the p53 inhibitor significantly reduced loss of HCs and SGNs, and subsequently improved hearing. In summary, our findings indicate that REST has a protective role in AHL, and that its deficiency upregulates p53 and induces cochlear cell apoptosis, which that leads to deafness.

The impact of hearing impairment and hearing aid use on progression to mild cognitive impairment in cognitively healthy adults: An observational cohort study

INTRODUCTION

We assessed the association of self-reported hearing impairment and hearing aid use with cognitive decline and progression to mild cognitive impairment (MCI).

METHODS

We used a large referral-based cohort of 4358 participants obtained from the National Alzheimer's Coordinating Center. The standard covariate-adjusted Cox proportional hazards model, the marginal structural Cox model with inverse probability weighting, standardized Kaplan-Meier curves, and linear mixed-effects models were applied to test the hypotheses.

RESULTS

Hearing impairment was associated with increased risk of MCI (standardized hazard ratio [HR] 2.58, 95% confidence interval [CI: 1.73 to 3.84], P = .004) 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 (HR 0.47, 95% CI [0.29 to 0.74], P = .001). No difference in risk of MCI was observed between individuals with normal hearing and hearing-impaired adults using hearing aids (HR 0.86, 95% CI [0.56 to 1.34], P = .51).

DISCUSSION

Use of hearing aids may help mitigate cognitive decline associated with hearing loss.

Embedding audiological screening within memory clinic care pathway for individuals at risk of cognitive decline-patient perspectives

Background

With the evolving knowledge on hearing as a potentially modifiable mid-life risk factor for dementia, identification of people at risk becomes increasingly important. People with mild cognitive impairment (MCI) presenting to specialist memory services represent a key “at-risk” target population for audiological evaluation, but few services have established this pathway. This study sought to examine the patient experience and understanding of this process.

Methods

All patients with MCI attending a tertiary referral memory service referred for audiology review were contacted. A patient survey was delivered over the phone. Outpatient letters and the memory clinic database were reviewed.

Results

Twenty patients with MCI were included in the survey. Eight (8/20, 40%) had self-reported hearing loss. Upon formal audiological assessment seventeen (17/20, 85%) had objective evidence of hearing loss; nine (9/17, 52.9%) with mild-moderate and eight (8/17, 47%) with moderate-severe hearing loss. Only six patients (6/20, 30%) recalled having the rationale behind having a hearing test as part of their memory work-up explained to them. However, the majority (15/20, 75%) felt a hearing test was an important part of their memory assessment. Just seven patients overall (7/20, 35%) identified a link between hearing-loss and cognition. All patients who provided feedback on the service itself made positive comments, although (4/20, 20%) felt they did not get adequate information about the results.

Conclusions

A significant proportion of people with MCI had de-novo evidence of hearing impairment upon assessment. Patients are satisfied with incorporating audiological evaluation into a memory clinic assessment, however clear communication around indication, recommendations, and follow-up ensuring compliance is required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-021-02701-0.

Self-reported hearing difficulty increases 3-year risk of incident cognitive impairment: The role of leisure activities and psychological resilience

OBJECTIVE

Although hearing difficulty is associated with cognitive impairment, little is known about the potential mechanisms involved. This study assessed the mediating effects of leisure activities and psychological resilience on the association between hearing difficulty and cognitive impairment.

METHODS

Two waves of Chinese Longitudinal Healthy Longevity Survey (2011-2014) were used in the current analysis. Hearing difficulty, leisure activities and psychological resilience were measured at baseline. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination. The data were analyzed using generalized structural equation modeling with adjustment for confounding factors.

RESULTS

Of the 4267 participants at baseline, 33.5% (1430) reported hearing difficulty. The incidence of cognitive impairment was 15.3% (651) during the 3-year follow-up. Hearing difficulty increased the risk of cognitive impairment (odds ratio [OR] = 1.59, 95% confidence intervals [CI]: 1.26-1.92). Leisure activities and psychological resilience partly mediated the association between hearing difficulty and cognitive impairment. Hearing difficulty was negatively related to leisure activities (β = -0.23, 95% CI: -0.41 to -0.05) and psychological resilience (β = -0.34, 95% CI: -0.57 to -0.11). Furthermore, leisure activities (OR = 0.92, 95% CI: 0.89-0.96) and psychological resilience (OR = 0.95, 95% CI: 0.93-0.98) would significantly decrease the risk of cognitive impairment.

CONCLUSIONS

Hearing difficulty was associated with the incidence of cognitive impairment in older adults. Leisure activities and psychological resilience mediated the relationship. Participation in leisure activity and promoting psychological resilience may be candidate interventions in preventing cognitive impairment among the individuals with hearing difficulty.

Hearing Loss and Dementia: A Meta-Analysis of Prospective Cohort Studies

Background: Consensus is lacking with regard to whether hearing loss is an independent risk factor for dementia. We therefore conducted a meta-analysis to clarify the relationship of hearing loss and dementia.

Methods: Prospective cohort studies investigating the association between hearing loss and the incidence of dementia in a community-derived population were included by searching electronic databases that included PubMed, Embase, and Cochrane's Library. A random-effects model was adopted to combine the results.

Results: Fourteen cohorts including 726,900 participants were analyzed. It was shown that hearing loss was independently associated with dementia [adjusted hazard ratio (HR): 1.59, 95% confidence interval (CI): 1.37 to 1.86, p < 0.001; I² = 86%]. Sensitivity analysis sequentially excluding any of the individual studies included showed similar results. Subgroup analysis according to the diagnostic methods for hearing loss, validation strategy for dementia, follow-up duration, and adjustment of apolipoprotein E genotype also showed consistent results (p-values for subgroup differences all > 0.05). Meta-analysis with five studies showed that hearing loss was also connected to higher risk of Alzheimer's disease (adjusted HR: 2.24, 95% CI: 1.32 to 3.79, p = 0.003; I² = 2%).

Conclusions: Hearing loss may increase the risk of dementia in the adult population. Whether effective treatment for hearing loss could reduce the incidence of dementia should be explored in the future.

Leisure activities and psychological wellbeing reduce the risk of cognitive impairment among older adults with hearing difficulty: A longitudinal study in China

OBJECTIVES

. We used longitudinal cohort data to examine the effect of leisure activities and psychological wellbeing on the risk of cognitive impairment among Chinese older adults with hearing difficulty (HD).

STUDY DESIGN

. This prospective cohort study included 10,341 cognitively normal individuals aged 65 years or more at baseline from the Chinese Longitudinal Healthy Longevity survey (from 2002 to 2011).

MAIN OUTCOME MEASURES

. Hearing difficulty, leisure activities and psychological wellbeing were measured at baseline. Cognitive function was assessed using the Chinese version of the Mini-Mental State Examination (MMSE). Cognitive impairment was defined as an MMSE score of less than 18 points.

RESULTS

. During a median follow-up of 5.6 years (59,869 person-years), 2,614 participants developed cognitive impairment. Cox proportional hazards models showed that the multi-adjusted hazard ratio (HR, 95% confidence interval) of cognitive impairment was 1.42 (1.28-1.58) for HD. Participants with a healthy lifestyle had a lower risk of cognitive impairment (HR = 0.77, 95% CI 0.69-0.85). Furthermore, participants with HD and a healthy lifestyle (HR = 1.67, 95% CI 1.27-2.18) had a lower HR of cognitive impairment than those with HD and an unhealthy lifestyle (HR = 1.86, 95% CI 1.61-2.14). A healthy lifestyle also delayed the onset of cognitive impairment by 0.50 years in people with HD.

CONCLUSIONS

. HD was associated with an increased risk of cognitive impairment, but a healthy lifestyle may decrease the risk of cognitive impairment related to HD and delay the onset of cognitive impairment.

Does self-reported hearing difficulty decrease older adults' cognitive and physical functioning? The mediating role of social isolation

OBJECTIVES

We used longitudinal cohort data to explore the association between self-reported hearing difficulty (SHD) and cognitive as well as physical functioning, and whether the association is mediated by social isolation.

STUDY DESIGN

16,786 observations from participants aged 65 and older in two waves of the Chinese Longitudinal Healthy Longevity Survey, a community-based cohort study, were analyzed.

MAIN OUTCOME MEASURES

Cognitive impairment was assessed using the Chinese version of the Mini Mental State Examination (MMSE). Activities of daily living (ADL) and instrumental activities of daily living (IADL) were used as indicators of physical functioning.

RESULTS

Generalized structural equation modelling (GSEM) analysis showed that SHD increased the risk cognitive impairment (odds ratio [OR] = 2.93, 95 % confidence intervals [CI] 2.61-3.30), ADL disability (OR = 2.10, 95 % CI 1.86-2.38), and IADL disability (OR = 2.39, 95 % CI 2.12-2.68). Social isolation mediated the association of SHD with cognitive functioning, but not with physical functioning. SHD was positively associated with social isolation (OR = 1.23, 95 % CI 1.07-1.42), and social isolation was significantly associated with cognitive impairment (OR = 2.09, 95 % CI 1.74-2.50). Indirect effects of SHD explained 12.3 % of the variance in cognitive impairment via social isolation.

CONCLUSIONS

SHD was associated with adverse cognitive and physical functioning in older adults. Cognitive but not physical functioning was indirectly influenced by SHD via social isolation.