Age-related Hearing Loss Is Strongly Associated With Cognitive Decline Regardless of the APOE4 Polymorphism

Cardiovascular Diseases and Sensorineural Hearing Loss-A Systematic Review of the Literature

OBJECTIVES

To assess the relationship of cardiovascular disease (CVD) and sensorineural hearing loss (SNHL).

DATABASES REVIEWED

Ovid MEDLINE, Web of Science, Scopus, and Cochrane.

METHODS

A systematic review was performed. Studies were identified using Ovid MEDLINE, Web of Science, Scopus, and Cochrane from 1946 to 2023. Per Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, abstracts were screened for primary review. Full texts were reviewed for secondary review.

RESULTS

There were 3,440 unique abstracts screened. After primary review of abstracts and secondary full text review, 68 articles were included. The relationship between SNHL and the following CVDs, risk factors, and interventions were ascertained: coronary artery bypass graft (CABG) surgery, coronary artery disease (CAD), carotid stenosis (CS), myocardial infarction (MI), percutaneous coronary intervention (PCI), other arteriosclerosis, cerebral small vascular disease, cerebrovascular accident (CVA), transient ischemic attack (TIA), peripheral vascular disease (PVD), hyperlipidemia (HLD), hypertension (HTN), and diabetes mellitus (DM). CABG and CAD were consistently associated with SNHL. DM was associated with SNHL, but HTN and HLD were not consistently associated.

CONCLUSIONS

There is a complex relationship between CVDs and SNHL. CABG and CAD were consistently associated with SNHL. DM was associated with SNHL, but other CVD risk factors (HTN and HLD) did not appear to consistently correlate with SNHL, raising consideration that SNHL is a later finding in those with CVD.

The biphasic impact of apolipoprotein E ε4 allele on age-related hearing loss

Both the ε4 variant of the apolipoprotein E (APOE) gene and hearing loss are well-known risk factors for Alzheimer's disease. However, previous studies have produced inconsistent findings regarding the association between APOE genotypes and hearing levels, necessitating further investigation. The aim of this study was to investigate the relationship between APOE genotypes and hearing levels. This retrospective study analyzed clinical data from a clinical data warehouse of seven affiliated Catholic Medical Center hospitals. The study included 1,162 participants with records of APOE genotypes, audiometric tests, and cognitive function tests. In Generalized linear mixed model analysis, ε4 carriers exhibited lower pure tone audiometry thresholds with an estimate of -0.353 (SE = 0.126, p = 0.005). However, the interaction term for age and APOE ε4 had a coefficient of 0.577 (SE = 0.214 p = 0.006), suggesting that the APOE ε4 gene may accelerate hearing deterioration with age. Subgroup analysis based on an age cut-off of 75 revealed that ε4 carriers had better hearing at younger ages, but showed no significant difference at older ages. These results indicate that the ε4 allele may have a biphasic effect on hearing levels depending on age.

The impact of hearing aids on cognitive function and quality of life in patients with hearing impairment: A cross-sectional study

OBJECTIVE

Age-related cognitive decline involves a complex set of factors. Among these factors, hearing loss is considered to have a significant impact, but the effect of hearing aid use remains unresolved. The purpose of this study was to evaluate the effects of hearing aid use by simultaneously assessing various factors not only cognitive function but also frailty, anxiety, depression, and quality of life (QOL) in patients with hearing loss.

METHODS

The cross-sectional study at the Hearing Aid (HA) Center was conducted between 2020 and 2021. Initially, associations with cognitive function, QOL, frailty, and mental state among patients with hearing loss were examined, irrespective of whether they wore a hearing aid or not. Next, these patients were divided into HA users (using HA for more than 1 year) and non-users (no prior use of HA) with 42 patients in each group. The average age and 6-frequency pure tone audiometry (PTA) was 74.5 ± 6.5 years and 50.6 ± 12.1 dB, respectively. All participants filled out the questionnaire about their life style, medical condition. Mini-Mental State Examination (MMSE) for cognitive function, Hospital Anxiety and Depression Scale for mental state, Short Form 36 version 2 (SF-36v2) for QOL, and Kihon Checklist for frailty were compared between HA users and non-users and correlated with the auditory data (PTA and speech discrimination).

RESULTS

Among 84 patients, 40 had an MMSE score ≦26. All eight scores and three components of SF-36v2 were lower than those of the control group. The patients with hypertension were significantly more in HA user than in non-HA user, whereas there was no difference in diabetes, heart attack, stroke and education. Although HA users were older and showed hypertension more their PTA was worse than that of non-users, MMSE scores were not different between the groups. MMSE scores correlated with both PTA and speech discrimination in non-users but not in HA users. However, a multivariate analysis of the effect of HA use on MMSE scores adjusting for age, hypertension, and hearing loss, could not be revealed. The vitality and mental component summary of the SF-36v2 was better in HA users than in non-users.

CONCLUSION

Elderly patients with hearing loss were cognitively impaired and had low QOL. HA users showed better QOL score than non-HA user, especially about the mental condition. The absence of a correlation between MMSE scores and hearing loss in HA users suggests the potential use of HA in preventing cognitive decline.

An external focus promotes motor learning of an aiming task in individuals with hearing impairments

Research has shown that external relative to internal focus (IF) instructions may improve motor performance as well as cognitive function (e.g., attentional stability and task-focus). The aim of the study was to examine the influence of attentional focus instructions on skill acquisition and learning of an aiming task in individuals with hearing impairments. The participants (N = 39, Mage = 17.87 ± 1.88 years) performed a bowling task with their dominant hand to knock down as many pins as possible. On day 1, they were randomly divided into three attentional focus groups; IF (focus on your throwing hand), external focus (EF) (focus on the pins), and control (no-focus) instructions. Each participant performed 36 trials, divided into 3 blocks of 12 trials. Attentional focus instructions were given before each block, with a brief reminder provided after each 3 trials. On day 2, retention and transfer (further distance) tests were performed. Results showed that while there were no significant differences between groups in the pre-test, the EF group outperformed both IF and control groups in retention and transfer tests. No significant difference was found between the control and IF. The findings suggest that the advantages of the external relative to the IF and no-focus instructions may generalize to individuals with hearing impairments.

Charting Alzheimer's Disease and Dementia: Epidemiological Insights, Risk Factors and Prevention Pathways

Alzheimer's disease (AD), the most common cause of dementia, is a complex and multifactorial condition without cure at present. The latest treatments, based on anti-amyloid monoclonal antibodies, have only a modest effect in reducing the progression of cognitive decline in AD, whereas the possibility of preventing AD has become a crucial area of research. In fact, recent studies have observed a decrease in dementia incidence in developed regions such as the US and Europe. However, these trends have not been mirrored in non-Western countries (Japan or China), and the contributing factors of this reduction remain unclear. The Lancet Commission has delineated a constrained classification of 12 risk factors across different life stages. Nevertheless, the scientific literature has pointed to over 200 factors-including sociodemographic, medical, psychological, and sociocultural conditions-related to the development of dementia/AD. This narrative review aims to synthesize the risk/protective factors of dementia/AD. Essentially, we found that risk/protective factors vary between individuals and populations, complicating the creation of a unified prevention strategy. Moreover, dementia/AD explanatory mechanisms involve a diverse array of genetic and environmental factors that interact from the early stages of life. In the future, studies across different population-based cohorts are essential to validate risk/protective factors of dementia. This evidence would help develop public health policies to decrease the incidence of dementia.

APOE-ε4 is not associated with pure-tone hearing thresholds, visual acuity or cognition, cross-sectionally or over 3 years of follow up in the Canadian Longitudinal Study on Aging

INTRODUCTION

Hearing loss and diminished visual acuity are associated with poorer cognition, but the underlying mechanisms are not understood. The apolipoprotein (APOE) ε4 allelic variant may drive the associations. We tested whether APOE-ε4 allele count (0, 1, or 2) was associated with declines in memory, executive function, pure-tone hearing threshold averages, and pinhole-corrected visual acuity among participants in the Canadian Longitudinal Study on Aging (CLSA).

METHODS

Multivariable linear mixed regression models were utilized to assess associations between APOE-ε4 allele count and each of the outcome variables. For each main effects model, interactions between APOE-ε4 and sex and age group (45-54-, 55-64-, 65-74-, and 75-85 years) respectively, were analyzed.

RESULTS

Significant associations were not observed in main effects models. Models including APOE-ε4 * age (but not APOE-ε4 * sex) interaction terms better fit the data compared to main effects models. In age group-stratified models, however, there were minimal differences in effect estimates according to allele count.

CONCLUSION

APOE-ε4 allele count does not appear to be a common cause of sensory-cognitive associations in this large cohort.

Cataract Surgery and Chronic Kidney Disease: A Hospital-based Prospective Cohort Study

Objective Cataract and chronic kidney disease (CKD) occur with increasing frequency with age and share common risk factors including smoking, diabetes, and hypertension. We evaluated the risk of incident cataract surgery in patients with non-dialysis-dependent CKD and dialysis-dependent CKD compared to non-CKD patients, while taking into account the competing risk of death. Methods The participants included 1,839 patients from Sado General Hospital enrolled in the Project in Sado for Total Health (PROST) between June 2008 and December 2016 (54% men; mean age, 69 years). Among these patients, 50%, 44%, and 6% had non-CKD, non-dialysis-dependent CKD, and dialysis-dependent CKD, respectively. Results During a median follow-up of 5.6 years (interquartile range, 4.7-7.1), 193 participants underwent cataract surgery [18.7 (95% confidence interval (CI), 16.2-21.5)/1,000 person-years] and 425 participants died without undergoing cataract surgery [41.0 (95% CI, 37.4-45.2)/1,000 person-years]. The cumulative incidence of cataract surgery was the highest in the dialysis-dependent CKD group, followed by the non-dialysis-dependent CKD and non-CKD groups (log-rank p=0.002). After adjusting for potential confounding factors, the dialysis-dependent CKD group [hazard ratio (HR) 2.48; 95% CI 1.43-4.31], but not the non-dialysis-dependent CKD group (HR, 1.01; 95% CI 0.74-1.38), had a higher risk of cataract surgery than the non-CKD group. However, this association was no longer significant according to a competing risk analysis (sub-hazard ratio, 1.67; 95% CI 0.93-3.03). Conclusion Dialysis-dependent CKD patients were found to have an increased risk of cataract surgery; however, the association was attenuated and no longer significant when death was considered a competing risk.

Adjunct Methods for Alzheimer's Disease Detection: A Review of Auditory Evoked Potentials

The auditory afferent pathway as a clinical marker of Alzheimer's disease (AD) has sparked interest in investigating the relationship between age-related hearing loss (ARHL) and AD. Given the earlier onset of ARHL compared to cognitive impairment caused by AD, there is a growing emphasis on early diagnosis and intervention to postpone or prevent the progression from ARHL to AD. In this context, auditory evoked potentials (AEPs) have emerged as a widely used objective auditory electrophysiological technique for both the clinical diagnosis and animal experimentation in ARHL due to their non-invasive and repeatable nature. This review focuses on the application of AEPs in AD detection and the auditory nerve system corresponding to different latencies of AEPs. Our objective was to establish AEPs as a systematic and non-invasive adjunct method for enhancing the diagnostic accuracy of AD. The success of AEPs in the early detection and prediction of AD in research settings underscores the need for further clinical application and study.

Probability Distributions for Associations Between Cognitive Screening and Pure-tone Thresholds in Older Adults

OBJECTIVES

Lower general cognitive function is frequently reported in older adults with elevated pure-tone thresholds. Here, we examined reason(s) for this association, including whether this relationship is dependent on the frequency range or extent of hearing loss and cognitive screening performance.

DESIGN

Linear regression was used to examine associations between better-ear pure-tone thresholds and Mini-Mental Status Exam (MMSE) performance in a cross-sectional sample of relatively healthy older adults (N = 508; 68% women, 60-89+ years; M age = 72). Quantile regression was also used to identify the ranges of 0.5 and 4.0 kHz thresholds and MMSE scores where these variables exhibited significant associations.

RESULTS

MMSE scores and pure-tone thresholds exhibited small but significant associations, particularly for better-ear 0.5 kHz thresholds. This hearing threshold and cognitive screening association was present among participants with better hearing, including the oldest older adults. There was limited evidence for mediating health condition effects on this association. An item analysis of the MMSE revealed that the MMSE and pure-tone threshold associations were largely due to the delayed recall item of the MMSE.

CONCLUSIONS

Together, the small effect results are consistent with the extant literature and suggest that there are multiple reasons for modest pure-tone threshold and cognitive screening performance associations.

Stroke incidence and chronic kidney disease: a hospital-based prospective cohort study

AIM

This prospective cohort study aimed to (i) examine stroke incidence and stroke subtypes by chronic kidney disease (CKD) stage, (ii) examine whether CKD patients with or without proteinuria have a high risk of stroke independent of traditional cardiovascular risk factors, and (iii) determine precise estimates of stroke risk by CKD stage while accounting for competing mortality risk.

METHODS

Participants were 2,023 patients enrolled in the Project in Sado for Total Health between June 2008 and December 2016 (55% men; mean age, 69 years), of whom 52% had CKD (stage 1-2, 10%; G3a, 48%; G3b, 17%; G4-5, 11%; and G5D, 14%).

RESULTS

During a median follow-up of 5.7 years, 157 participants developed stroke and 448 died without developing stroke. Most stroke cases were ischemic among non-dialysis-dependent CKD participants, but the relative frequency of ischemic stroke was near that of intracerebral hemorrhage among dialysis-dependent CKD participants. After adjustment, stage 1-2 (hazard ratio (HR), 2.97; 95% confidence interval (CI), 1.60 to 5.51) and stage G3-5 participants with proteinuria (HR, 2.50; 95% CI, 1.56 to 4.02), but not stage G3-5 participants without proteinuria (HR, 0.64; 95% CI, 0.38 to 1.08), had a higher stroke risk compared to non-CKD participants. In competing risk analyses, the association was attenuated but remained significant.

CONCLUSION

Although the distribution of stroke subtypes differed, CKD participants with proteinuria and those with CKD stage 5D had a 2- and 4-times higher risk of stroke, respectively, than that of non-CKD participants, after accounting for competing mortality risk and traditional risk factors. This article is protected by copyright. All rights reserved.

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). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment and determination of any bias in testing, potential for managing hearing loss for prevention of dementia and cognitive decline, or the potential to reduce dementia-related symptoms through the management of hearing loss. Addressing these research gaps and how results are then translated for clinical use may prove paramount for dementia prevention, management, and overall health of older adults.

Polypharmacy, chronic kidney disease, and incident fragility fracture: a prospective cohort study

INTRODUCTION

Polypharmacy is associated with an increased risk of fracture in aging populations, but no study has accounted for the impact of kidney function on this association. This study aimed to examine the association between polypharmacy and incident fragility fracture based on chronic kidney disease (CKD) status.

MATERIALS AND METHODS

Participants were 2023 patients (55% men; mean age, 69 years) of Sado General Hospital enrolled in the Project in Sado for Total Health (PROST) between June 2008 and December 2016. Among these, 65%, 28%, and 7% had non-CKD, non-dialysis-dependent CKD, and dialysis-dependent CKD, respectively. Multivariable Cox proportional hazards analysis was conducted with adjustments for potential confounders.

RESULTS

Prevalences of polypharmacy (≥ 5 medications) and hyperpolypharmacy (≥ 10 medications) among participants were 43% and 9% for non-CKD, 62% and 23% for non-dialysis-dependent CKD, and 85% and 34% for dialysis-dependent CKD, respectively. During a median follow-up of 5.6 years, 256 fractures occurred. More medications were associated with a higher risk of fractures. Specifically, compared to participants without polypharmacy, adjusted hazard ratios were 1.32 (95% CI 0.96-1.79) and 1.99 (1.35-2.92) for those with polypharmacy and hyperpolypharmacy, respectively, after adjusting for osteoporosis risk factors, CKD status, and comorbidities. No effect modification by CKD status was observed (interaction P = 0.51). Population-attributable fractions of hyperpolypharmacy for fracture were 9.9% in the total cohort and 42.1% in dialysis-dependent CKD patients.

CONCLUSION

Hyperpolypharmacy is associated with an increased risk of fragility fracture regardless of CKD status, and has a strong impact on incident fragility fractures in dialysis-dependent CKD patients.

Hearing Impairment and Cognition in an Aging World

With the increasing number of older adults around the world, the overall number of dementia cases is expected to rise dramatically in the next 40 years. In 2020, nearly 6 million individuals in the USA were living with Alzheimer's disease, the most common type of dementia, with anticipated growth to nearly 14 million by year 2050. This increasing prevalence, coupled with high societal burden, makes prevention and intervention of dementia a medical and public health priority. As clinicians and researchers, we will continue to see more individuals with hearing loss with other comorbidities including dementia. Epidemiologic evidence suggests an association between hearing loss and increased risk of dementia, presenting opportunity for targeted intervention for hearing loss to 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). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment, and potential of aural rehabilitation. Addressing these research gaps and how results are then translated for clinical use is paramount for dementia prevention and overall health of older adults.

Prevalence of usage of hearing aids and its association with cognitive impairment in Japanese community-dwelling elders with hearing loss

OBJECTIVE

Hearing loss is a risk factor for cognitive impairment, and the use of a hearing aid (HA) may prevent cognitive decline alongside hearing loss. We aimed to elucidate the prevalence of self-reported HA usage in Japanese community-dwelling elders with hearing loss, and the effect of hearing and HA on cognitive impairment.

METHODS

A total of 1193 participants, who had audiometric defined hearing loss and were aged 60 years or over, had their cumulative 3260 observations followed up for 10 years from a large cohort of a Japanese study. Association between hearing (pure-tone average threshold level at 500, 1000, 2000, and 4000 Hz from the better hearing ear: PTABHE) and HA usage with cognitive impairment (total score of Mini-Mental State Estimation was under 27 or diagnosed as dementia) was analyzed using generalized estimating equations.

RESULTS

The HA usage rate of the 1193 community-dwelling elders with hearing loss was 6% during the first involvement. The majority (59.2%) of HA users always used an HA. HA usage rate was 0.7% for the mild hearing loss group and 32.4% for the moderate or greater hearing loss group in the latest participating wave. PTABHE was significantly associated with cognitive impairment (odds ratio for every 10 dB 1.36; 95% CI 1.21-1.53, p<0.0001) after adjusting for age, sex, education, depressed mood, smoking status, alcohol intake, income, activity, obesity, histories of hypertension, dyslipidemia, ischemic heart disease, diabetes, stroke, ear disease, and occupational noise exposure. PTABHE was also significantly associated with cognitive impairment in the mild hearing loss group (odds ratio for every 10 dB 1.34; 95% CI 1.05-1.72, p = 0.020) and moderate hearing loss group (odds ratio for every 10 dB 1.82; 95% CI 1.27-2.61, p = 0.001). HA use showed a significant suppressive effect on cognitive impairment in those with moderate hearing loss who always use an HA (odds ratio 0.54; 95% CI 0.30-1.00, p = 0.049).

CONCLUSION

The prevalence of HA usage among Japanese community-dwelling elders with hearing loss is consistent, at around 10%. The hearing level remained a primary risk factor for cognitive impairment among elders with hearing loss after adjusting for several confounding factors. Regular HA use may have a protective effect on cognitive impairment in those with moderate hearing loss.