Cognitively stimulating activities and risk of probable dementia or cognitive impairment in the English Longitudinal Study of Ageing

Do missing teeth cause early-onset cognitive impairment? Re-examining the evidence using a quasi-natural experiment

PURPOSE

Multiple studies have reported a positive association between missing teeth and cognitive impairment. While some authors have postulated causal mechanisms, existing designs preclude assessing this.

METHODS

We sought evidence of a causal effect of missing teeth on early-onset cognitive impairment in a natural experiment, using differential exposure to fluoridated water during critical childhood years (ages 5-20 years) in England as the instrument. We coded missing teeth from 0 (≤ 12 missing) to 3 (all missing) and measured the association with cognitive impairment in the English Longitudinal Study of Ageing data (2014-5), covering 4958 persons aged 50-70 years.

RESULTS

We first replicated previous evidence of the strongly positive association of missing teeth with cognitive impairment (β = 0.25 [0.11, 0.39]), after adjusting for socio-demographic covariates, such as age, gender, education, and wealth. Using an instrumental variable design, we found that childhood exposure to water fluoridation was strongly associated with fewer missing teeth, with being exposed to fluoridated water during childhood (16 years) associated with a 0.96 reduction in the missing teeth scale (β = - 0.06 [- 0.10, - 0.02]). However, when using the instrumented measure of missing teeth, predicted by probability of fluoride exposure, we found that missing teeth no longer had an association with cognitive impairment (β = 1.48 [- 1.22, 4.17]), suggesting that previous oral health-cognitive impairment associations had unobserved confounding.

CONCLUSIONS

Our findings are consistent with the possibility that unobserved confounding leads to the oft-observed association between missing teeth and early-onset cognitive impairment, suggesting that the relationship is spurious rather than causal.

Self-reported mid- to late-life physical and recreational activities: Associations with late-life cognition

OBJECTIVE

Physical and recreational activities are behaviors that may modify risk of late-life cognitive decline. We sought to examine the role of retrospectively self-reported midlife (age 40) physical and recreational activity engagement - and self-reported change in these activities from age 40 to initial study visit - in predicting late-life cognition.

METHOD

Data were obtained from 898 participants in a longitudinal study of cognitive aging in demographically and cognitively diverse older adults (Age: range = 49-93 years, M = 75, SD = 7.19). Self-reported physical and recreational activity participation at age 40 and at the initial study visit were quantified using the Life Experiences Assessment Form. Change in activities was modeled using latent change scores. Cognitive outcomes were obtained annually (range = 2-17 years) using the Spanish and English Neuropsychological Assessment Scales, which measure verbal episodic memory, semantic memory, visuospatial processing, and executive functioning.

RESULTS

Physical activity engagement at age 40 was strongly associated with cognitive performance in all four domains at the initial visit and with global cognitive slope. However, change in physical activities after age 40 was not associated with cognitive outcomes. In contrast, recreational activity engagement - both at age 40 and change after 40 - was predictive of cognitive intercepts and slope.

CONCLUSIONS

Retrospectively self-reported midlife physical and recreational activity engagement were strongly associated with late-life cognition - both level of performance and rate of future decline. However, the data suggest that maintenance of recreational activity engagement (e.g., writing, taking classes, reading) after age 40 is more strongly associated with late-life cognition than continued maintenance of physical activity levels.

The longitudinal relationship between levels of cognitively stimulating leisure activity and positive and negative affect among older adults with MCI

BACKGROUND

The purpose of this study was to investigate the longitudinal relationship between different levels of cognitively stimulating leisure activity (CSLA) participation and different levels of positive and negative affect among older adults with mild cognitive impairment (MCI).

METHODS

Using a repeated-measured multivariate analysis of covariance (RM-MANCOVA), this study analyzed the Health and Retirement Study (HRS) data from 2012 to 2020 (N = 5932).

RESULTS

The results presented the following. (a) The high CSLA group showed higher positive affect and lower negative affect than the mid and low groups. Also, the mid-CSLA group presented higher positive affect and lower negative affect than the low CSLA group. (b) Both positive and negative affect showed significant differences between years and indicated a continuously declining slope year by year without exceptions. (c) The high CSLA group not only presented higher positive affect and lower negative affect during the period but also solely showed a rebounding feature in the declining slope on both emotions.

CONCLUSIONS

The findings of this study provide valuable support for the design and implementation of CSLA participation programs and clinical guidelines for older adults with MCI. The results highlight the importance of determining the optimal level of CSLA engagement that is required to promote emotional health and cognitive function in this population. Healthcare professionals and clinical practitioners can leverage the insights gained from this study to develop and deliver effective CSLA interventions tailored to the specific needs and capacities of older adults with MCI.

The relationship between volunteering and cognitive performance in older adults: A systematic review

OBJECTIVES

This systematic review aims to examine the relationship between cognition and volunteering in older adults, with a specific focus on domain-specific outcomes.

METHODS

In April 2023, a comprehensive search was conducted across multiple electronic databases including PubMed, Google Scholar, ScienceDirect, Web of Science, and Scopus. The inclusion criteria for the study were limited to longitudinal studies or randomized controlled trials (RCTs). The quality and risk of bias of the included articles were assessed using the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT).

RESULTS

Out of 3575 articles retrieved, 17 studies were eligible for inclusion in this review. The majority of these studies were conducted in high-income countries. Of the 17 studies reviewed, 16 found a positive association between volunteering and cognitive benefits.

CONCLUSION

The analysis of seventeen studies meeting the predefined inclusion criteria suggests a potential positive correlation between volunteering and cognitive function among older adults. Some demographic factors such as gender and education level were observed to have an influence on this relationship. It was found that older adults who engage in volunteering may exhibit better episodic memory, working memory, and verbal fluency compared to non-volunteers. However, due to limitations in the existing research and variations across studies, further investigation is needed to establish definitive conclusions.

Association between obesity and urinary incontinence in older adults from multiple nationwide longitudinal cohorts

BACKGROUND

Obesity and urinary incontinence (UI) among older adults, particularly older men, are yet to be fully explored. Utilizing multiple nationwide prospective longitudinal cohorts representative of the US, UK, and European samples, we examined the association of body mass index (BMI) and waist circumference (WC) with UI among both older women and men.

METHODS

We derived the data from multiple longitudinal cohorts that surveyed UI. Participants were asked if they had experienced urine leakage within the past 12 months or within the past six months. The measure of obesity was based on BMI and WC. We employed a random-effect logistic model to associate BMI and WC with UI, adjusting for covariates including age, race, education, residence area, marital status, number of children, smoking, drinking, hypertension, diabetes, cancer, stroke, functional ability, and cognitive impairment. We visualized the associations by using restricted cubic spline curves.

RESULTS

A total of 200,717 participants with 718,822 observations are included in the baseline analysis. Compared to those without UI, both female and male participants with UI demonstrate a higher BMI and WC. Among females, the fully adjusted models show linear associations between BMI, WC, and UI (Ps < 0.001). However, we observe U-shaped associations of BMI, WC with UI among males. The lowest likelihood of having UI is found among male participants with a BMI between 24 and 35 kg/m2.

CONCLUSIONS

Interventions aimed at preventing UI among older adults must take sex into account. Weight loss intervention could be an effective treatment among older females who are overweight and with obesity as well as older males with obesity rather than all older males.

Effect of a combined program of running exercise and environmental enrichment on memory function and neurogenesis markers in amyloid-beta-induced Alzheimer-like model

Objectives

It is urgent to develop non-pharmacological interventions or multifactor combination approaches to combat Alzheimer's disease (AD). The effect of exercise (EX) combined with environmental enrichment (EE) on behavioral phenotypes and neurogenesis markers in an Alzheimer-like rat model was investigated.

Materials and Methods

The groups consisted of AD, sham-operated, AD+EX, AD+EE, and AD+EX+EE. AD was produced by injection of amyloid-beta (1-42, 6 µg) intrahippocampally, and a daily treadmill for 3 consecutive weeks was used for EX animals. EE was a large cage (50× 50× 50 cm) containing differently shaped objects. Spatial learning and memory were evaluated in the Morris water maze (MWM), and a shuttle box was used to evaluate inhibitory avoidance memory. RT-PCR was performed to assess the expression of early neurogenesis markers, DCX, and Sox2 within the hippocampus.

Results

Pretreatment with exercise and EE, both individually and in combination, could provide protection from memory impairments in AD rats. Combined treatment led to a significantly more pronounced improvement in memory deficits of AD rats than either paradigm alone. Combination therapy with exercise and EE could also reverse the passive avoidance memory impairment and hippocampal DCX expression of AD rats to the control levels.

Conclusion

These data suggest that exercise in combination with cognitive engagement can provide a non-pharmacological and multidomain policy that may prevent or delay AD symptoms.

Does Voluntary Work Contribute to Cognitive Performance? - An International Systematic Review

Introduction

There is a need for knowledge on activities that can reduce cognitive decline and dementia risk. Volunteering is a productive activity that entails social, physical, and cognitive functions. Therefore, volunteering could be a protective factor for cognitive loss. Thus, this review aims to examine the associations between volunteering and volunteers' cognition and to identify influencing variables.

Methods

Six international literature databases were searched for relevant articles published between 2017 and 2021 (ALOIS, CENTRAL, CINAL, Embase, PsycINFO, PubMed). Quantitative studies of all study designs were included. The primary outcome was the volunteers' cognition measured by objective, internationally established psychometric function tests. Two authors independently assessed the eligibility and quality of the studies. A narrative synthesis was performed using all studies included in this review. The methodology was in line with the PRISMA guidelines.

Results

Fourteen studies met the inclusion criteria and were included. Seven of the included studies confirmed that volunteering positively affects the volunteers' cognitive function. Two other studies identified an association between volunteer activity and volunteers' cognition using cross-sectional measurements. In particular, women and people with a low level of education benefit from the positive effects and associations. The study quality of the included articles was moderate to weak.

Discussion

Our review suggests that volunteering can improve volunteers' cognition. Unfortunately, little attention is given to specific volunteer activities and the frequency of engagement. Additionally, more attention is needed on various risk factors of cognitive impairment.

Urbanization and Cognitive Function Among Middle-Aged and Old Adults in China

OBJECTIVES

Our study examined the effect of urbanization on cognitive function and its possible pathways among Chinese middle-aged and older adults independent of the influence of health-selective migration.

METHODS

Using data from the China Health and Retirement Longitudinal Study, we compared cognitive function among three groups (urbanized-rural residents, rural nonmigrants, and urban nonmigrants). Logistic regression and structural equation models were applied to explore the impact of urbanization on cognitive function and the potential mechanisms.

RESULTS

Compared with the urbanized-rural group, urban nonmigrants had better cognitive function, with a significant coefficient of 1.56 (95% CI: 1.22, 1.89) for global cognition scores and 0.37 (95% CI: 0.22, 0.53) for episodic memory scores. The rural nonmigrants had the worst cognitive function (β = -0.79, 95% CI: -1.04, -0.55) and lower scores of mental intactness (β = -0.65, 95% CI: -0.84, -0.57) and episodic memory (β = -0.14, 95% CI: -0.26, -0.03). The association between urbanization and cognitive function was mainly mediated by income and living conditions among middle-aged and older adults.

DISCUSSION

Rural people who experienced planned urbanization in China had higher cognitive scores than rural non-migrants. Urbanization could thus have a beneficial and cumulative effect on cognitive function. Improvements in living conditions and changes in income are the main drivers behind the relationship. However, urbanization could compensate for the negative impact on cognitive function from disadvantaged early-life conditions, but it cannot completely eliminate the gap between urbanized-rural people and urban nonmigrants.

Observational studies in Alzheimer disease: bridging preclinical studies and clinical trials

Recent high-profile failures of Alzheimer disease treatments at the clinical trial stage have led to renewed efforts to identify and test novel interventions for Alzheimer disease and related dementias (ADRD). In this Perspective, we highlight the importance of including well-designed observational studies as part of these efforts. Observational research is an important cornerstone for gathering evidence on risk factors and causes of ADRD; this evidence can then be combined with data from preclinical studies and randomized controlled trials to inform the development of effective interventions. Observational study designs can be particularly beneficial for hypothesis generation, posing questions that are unethical or impractical for a trial setting, studying life-course associations, research in populations typically not included in trials, and public health surveillance. Here, we discuss each of these situations in the specific context of ADRD research. We also highlight novel approaches to enhance causal inference and provide a timely discussion on how observational epidemiological studies help provide a bridge between preclinical studies and successful interventions for ADRD.

Association Between Internet Use, Cognitive Function, and Globus Pallidus Volumes: A Study Among the Elderly in Chinese Communities

Background

Previous studies have linked internet use with several beneficial outcomes for brain health, but there is little data on this among older Chinese.

Objective

The goal of this study was to explore the association between internet use and cognitive impairment and to explore the possible mechanisms by which internet use prevents cognitive decline.

Methods

The current study consisted of two cohorts: one from the China Longitudinal Aging Study (CLAS), which included 610 older adults with mild cognitive impairment (MCI), 192 with dementia, and 2,218 healthy older adults; the second cohort included 39 healthy adults from the Shanghai brain health foundation (SHBHF2016001), who underwent T1 cranial magnetic resonance imaging at baseline, from which their volumes of the hippocampus, amygdala, and globus pallidus were calculated. Moreover, they were also followed up for 1 year. Through standardized questionnaires, detailed general demographic information and internet use information was obtained. The cognitive diagnosis of each participant was made by attending psychiatrists at baseline, and their overall cognitive function was assessed by the mini-mental state examination (MMSE) and Montreal Cognitive Assessment (MoCA).

Results

In cohort 1, after controlling age, gender, smoker, tea drinker, take exercise, diabetes, and hypertension, we found that internet use was associated with MCI (P = 0.015, OR = 0.478, 95% CI: 0.264~0.867), but not for dementia (P = 0.205, OR = 0.393, 95% CI: 0.093~1.665). In cohort 2, we found that the globus pallidus volume of internet users was significantly larger than that of non-users, and the MMSE change score was lower (P < 0.05). The results of partial correlation analysis (controlled for sex, age and education) showed that the change of MMSE value was positively correlated with the volume of left globus pallidus (r = 0.547, P = 0.004).

Conclusions

Internet use might be a protective factor for mild cognitive impairment among the Chinese elderly, and it may prevent a decline in cognitive decline by affecting the volume of the globus pallidus.

Health and self-perceived barriers to internet use among older migrants: a population-based study

Background

In older adults, including those with a migrant background, ill health is associated with less internet use. However, it is not known what are the specific self-perceived barriers to internet use among older migrants with different health conditions. The aim of this study was to investigate the associations between different health conditions and self-perceived barriers to internet use among older migrants.

Methods

We used the Care, Health and Ageing of Russian-speaking Minority in Finland (CHARM) study, which is a nationally representative survey of community-dwelling Russian-speaking adults aged ≥50 years living in Finland (N=1082, 57% men, mean age 63.2 years, standard deviation 8.4 years, response rate 36%). Postal survey data were collected in 2019. Health indicators were self-rated health (SRH), depressive symptoms, cognitive functioning, and doctor-diagnosed conditions. Linear regression analyses were used to investigate the associations between health indicators and a summary scale consisting of the following barriers of internet use: (1) internet use is too complicated and hard to learn; (2) having concerns about safety issues; (3) internet use is too expensive; (4) physical limitations hinder the internet use; (5) memory problems hinder the internet use. In addition, the two most commonly reported barriers (the first two) were examined separately using logistic regression analyses. The analyses were adjusted for age, sex, education, marital status, local language proficiency, and income support, and the health conditions, and were performed with weights accounting for the survey design and non-response.

Results

After adjustments, spine/back problems (b=0.13; p=0.049), depressive symptoms (b=0.40; p=0.007), and problems in learning new things (b=0.60; p<0.0005) were associated with higher level of overall barriers to internet use. In addition, a number of health conditions were associated with individual barriers, albeit some health conditions appeared protective.

Conclusions

In general, older migrants with declining health experience more barriers to internet use than their counterparts with better health. To provide better access to healthcare for older adults, including older migrants, rapidly changing devices, software and apps need to be modified and adapted for those with specific health-related needs.

Lifestyle Variables Such as Daily Internet Use, as Promising Protective Factors against Cognitive Impairment in Patients with Subjective Memory Complaints. Preliminary Results

Subjective memory complaints (SMCs) may be important markers in the prediction of cognitive deterioration. The aim of this study was to find associations between individual lifestyle factors, which may contribute to cognitive impairment (CI) in people with SMCs and to conduct a literature review on the relationship between internet use and CI in subjects over 50 years old, as a related factor. This was a case-controlled study that included 497 subjects aged over 50 years with SMCs who were recruited from 19 community pharmacies. Three screening tests were used to detect possible CIs, and individuals with at least one test result compatible with a CI were referred to primary care for evaluation. Having self-referred SMC increased the odds of obtaining scores compatible with CI and this factor was significantly related to having feelings of depression (OR = 2.24, 95% CI [1.34, 3.90]), taking anxiolytics or antidepressants (OR = 1.93, 95% CI [1.23, 3.05]), and being female (OR = 1.83, 95% CI [1.15, 2.88]). Thirty percent of our sample obtained scores compatible with CI. Age over 70 years increased the odds of obtaining scores compatible with CI. A high-level education, reading, and daily internet use were factors associated with a reduced risk of positive scores compatible with CI (37–91%, 7–18%, and 67–86%, respectively), while one extra hour television per day increased the risk by 8–30%. Among others, modifiable lifestyle factors such as reading, and daily internet usage may slow down cognitive decline in patients over 50 with SMCs. Four longitudinal studies and one quasi-experimental study found internet use to be beneficial against CI in patients over 50 years of age.