The association between vision impairment and cognitive outcomes in older adults: a systematic review and meta-analysis

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.

The Association of Vision and Hearing Impairment on Cognitive Function and Loneliness: Evidence From the Mexican Health and Aging Study

Objectives: We investigated whether self-reported vision and hearing were associated with cognitive function and loneliness among Mexican adults aged 50 and older. Methods: Mexican Health and Aging Study data. Vision/hearing status was self-reported (excellent-very good, good, fair-poor). Cognition was measured using nine tasks. Loneliness was measured using the UCLA Loneliness Scale. Analyses controlled for demographic and health characteristics. Results: Among 12,353 participants (mean age = 67, 58% female), poor vision, but not hearing, was associated with lower global cognition (β = -0.03, p < .05). Poor vision (OR = 1.57, 95% CI = 1.30-1.91) and hearing (OR = 1.35, 95% CI = 1.14-1.61) were associated with higher odds of being lonely after adjusting for demographics and comorbidities, but not when adjusting for limitations in daily activities and depressive symptoms. Discussion: Poor vision is a potentially modifiable risk factor for lower cognition and loneliness among Mexican adults. These associations are partly due to functional characteristics of older adults with poor vision.

The risk of dementia or cognitive impairment in patients with cataracts: a systematic review and meta-analysis

OBJECTIVES

The aim of this study was to investigate whether cataract disease is associated with the risk of developing dementia or cognitive impairment.

METHODS

A systematic search of the literature in PubMed, the Extracts Database (Embase), the Cochrane Library and the Web of Science databases was performed from the inception data of each database until 1 September 2022. Sensitivity analyses were performed to assess the robustness and reliability of the overall findings. All extracted data were statistically analyzed using Stata software v.16.0. Publication bias was assessed using funnel plots and the Egger test.

RESULTS

There were 11 publications included in this study, which consisted of 489,211participants, spanning 10 countries from 2012 to 2022. Aggregation suggested that cataracts were associated with cognitive impairment (odds ratio [OR] = 1.32; 95% CI: 1.21-1.43; I 2 = 45.4.%; p = 0.000). The presence of cataracts is significantly associated with an increased risk of developing all-cause dementia (relative risk [RR] = 1.17; 95% CI: 1.08-1.26; I2 = 0.0%; p = 0.000). In subgroup analyses, having cataracts may increase the risk of Alzheimer's disease (hazard ratio [HR] = 1.28; 95% CI: 1.13-1.45; I2 = 0.0%; p = 0.000) and vascular dementia (HR = 1.35; 95% CI = 1.06-1.73; I2 = 0.0%, p = 0.015). The data from the Egger's test showed no significant evidence of publication bias.

CONCLUSIONS

Cataracts are associated with the risk of cognitive impairment and dementia, including Alzheimer's disease, and vascular dementia.

Using Objective Vision Measures to Explore the Association of Vision Impairment With Cognition Among Older Adults in the United States

PURPOSE

To evaluate the association between vision impairment (VI) and cognitive function using objective measures.

DESIGN

Cross-sectional analysis with a nationally representative sample.

METHODS

The association between VI and dementia was investigated in a US population-based, nationally representative sample of Medicare beneficiaries, the National Health and Aging Trends Study (NHATS), a nationally representative sample of Medicare beneficiaries aged ≥65 years, using objective vision measures. Exposures included distance VI (>20/40), near VI (>20/40), contrast sensitivity impairment (CSI) (<1.55), any objective VI (distance and near visual acuity, or contrast), and self-reported VI. The main outcome measure was dementia status defined based on survey reports, interviews, and cognitive tests.

RESULTS

A total of 3026 adults were included in this study; the majority were female (55%) and White (82%). The weighted prevalence rates were 10% for distance VI, 22% for near VI, 22% for CSI, 34% for any objective VI, and 7% for self-reported VI. Across all measures of VI, dementia was more than twice as prevalent in adults with VI compared to their peers without (P < .001 for all). In adjusted models, all measures of VI were associated with higher odds of dementia (distance VI: OR 1.74, 95% CI 1.24-2.44; near VI: OR 1.68, 95% CI 1.29-2.18; CSI: OR 1.95, 95% CI 1.45-2.62; any objective VI: OR 1.83, 95% CI 1.43-2.35; self-reported VI: OR 1.86, 95% CI 1.20-2.89).

CONCLUSIONS

In a nationally representative sample of older US adults, VI was associated with increased odds of dementia. These results suggest that maintaining good vision and eye health may help preserve cognitive function in older age, although more research is needed to investigate the potential benefits of interventions that focus on vision and eye health on cognitive outcomes.

Longitudinal Analysis of Social Isolation and Cognitive Functioning among Hispanic Older Adults with Sensory Impairments

OBJECTIVES

Understanding the intersection of age, ethnicity, and disability will become increasingly important as the global population ages and becomes more diverse. By 2060, Hispanics will comprise 28% of the U.S.

POPULATION

This study examines critical associations between sensory impairment, social isolation, and cognitive functioning among Hispanic older adults.

METHODS

Our sample consisted of 557 Hispanic older adults that participated in Rounds 1-3 or Rounds 5-7 of the National Health and Aging Trends Study. Longitudinal mediation models across a three-year span were estimated using Mplus, with vision, hearing, and dual sensory impairments predicting cognitive functioning directly and indirectly through social isolation.

RESULTS

Findings indicated that cognitive functioning was concurrently and, in certain cases, longitudinally predicted by vision and dual sensory impairments and by social isolation. Contrary to expectations, vision and hearing impairments were not predictive of social isolation. Dual sensory impairment was associated with social isolation, yet no significant indirect associations were found for sensory impairments predicting cognitive functioning through social isolation.

DISCUSSION

The finding that social isolation did not mediate the relationship between sensory impairment and cognitive decline among Hispanic older adults in the U.S. is contrary to findings from other studies that were not specifically focused on this population. This finding may be evidence that culturally motivated family support and intergenerational living buffer the impact of sensory impairments in later life. Findings suggest that Hispanic older adults experiencing dual sensory impairments may benefit from interventions that foster social support and include family members.

Relationship between Claims-Based Frailty Index and Eye Care Utilization among Medicare Beneficiaries with Glaucoma

PURPOSE

To determine differences in eye care utilization by frailty levels among Medicare beneficiaries with glaucoma.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Medicare fee-for-service beneficiaries over 65 years of age with glaucoma, identified using International Classification of Diseases codes before July 1, 2014.

METHODS

By using a validated claims-based frailty index (range, 0-1), beneficiaries were classified as nonfrail/prefrail (0-0.19), mildly frail (0.20-0.29), and moderate-to-severely frail (≥ 0.30). Negative binomial regression analyses were used to estimate incident rate ratios (IRRs) of eye care utilization by frailty levels between July 1, 2014, and December 31, 2016.

MAIN OUTCOME MEASURES

Current Procedural Terminology codes for eye examinations and eye care-related office visits; eye care-related inpatient and emergency department (ED) encounters; eye care-related nursing facility and home-visit encounters; visual field (VF) and retinal nerve fiber layer (RNFL) OCT tests; and selective laser trabeculoplasties (SLTs) and glaucoma surgeries.

RESULTS

Among 76 260 Medicare beneficiaries with glaucoma, the mean age was 78.9 years (standard deviation, 7.8), female beneficiaries constituted 60.5%, and 78.7% of beneficiaries self-identified as non-Hispanic White. According to a claims-based frailty index, 79.5% of beneficiaries were nonfrail/prefrail, 17.1% were mildly frail, and 3.4% were moderate-to-severely frail. Moderate-to-severely frail beneficiaries were less likely than nonfrail/prefrail beneficiaries to have outpatient encounters (IRR, 0.85, 95% confidence interval [CI], 0.83-0.88); VF tests (IRR, 0.64, 95% CI, 0.60-0.67); RNFL OCT tests (IRR, 0.77, 95% CI, 0.73-0.81); SLT (IRR, 0.74, 95% CI, 0.60-0.92); and glaucoma surgery (IRR, 0.74, 95% CI 0.55-0.99), after adjusting for age, gender, glaucoma severity, race, and socioeconomic status. Compared with nonfrail/prefrail beneficiaries, moderate-to-severely frail beneficiaries had higher rates of inpatient/ED encounters (IRR, 5.03, 95% CI, 2.36-10.71) and nursing facility/home-visit encounters (IRR, 34.89, 95% CI, 14.82-82.13).

CONCLUSIONS

Compared with nonfrail/prefrail Medicare beneficiaries with glaucoma, beneficiaries with moderate-to-severe frailty had lower rates of eye care utilization in the outpatient setting and higher rates of utilization in acute care settings. This suggests that frail patients may receive less disease monitoring and fewer interventions for their glaucoma management.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Gout and risk of dementia, Alzheimer's disease or vascular dementia: a meta-epidemiology study

Objectives

The association between gout and dementia, Alzheimer's disease (AD), or vascular dementia (VD) is not fully understood. The aim of this meta-analysis was to evaluate the risk of all-cause dementia, AD, and VD in gout patients with or without medication.

Methods

Data sources were PubMed, Embase, the Cochrane Library, and reference lists of included studies. This meta-analysis included cohort studies assessing whether the risk of all-cause dementia, AD, and VD was associated with gout. The risk of bias was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was used to access the overall certainty of evidence. Risk ratios (RR) with 95% confidence intervals (CI) were pooled using a random-effects model, and publication bias was assessed with funnel plots and Egger's test.

Results

A total of six cohort studies involving 2,349,605 individuals were included in this meta-analysis, which were published between 2015 and 2022. The pooling analysis shows that the risk of all-cause dementia was decreased in gout patients [RR = 0.67, 95% CI (0.51, 0.89), I2 = 99%, P = 0.005, very low quality], especially in gout patients with medication [RR = 0.50, 95% CI (0.31, 0.79), I2 = 93%, P = 0.003, low quality]. The risk of AD [RR = 0.70, 95% CI (0.63, 0.79), I2 = 57.2%, P = 0.000, very low quality] and VD [RR = 0.68, 95% CI (0.49, 0.95), I2 = 91.2%, P = 0.025, very low quality] was also decreased in gout patients. Despite the large heterogeneity, the sensitivity analysis indicated that the results were robust, and there was little evidence of publication bias.

Conclusion

The risk of all-cause dementia, AD, and VD is decreased in gout patients, but the quality of evidence is generally low. More studies are still needed to validate and explore the mechanisms of this association.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022353312.