Physical activity attenuates the risk for dementia associated with aging in older adults with mild cognitive impairment. Findings from a population-based cohort study

Dementia: Common Syndromes and Modifiable Risk and Protective Factors

Dementia is an umbrella term for multiple conditions that lead to progressive cognitive decline and impaired activities of daily living. Neuropsychological evaluation is essential for characterizing the distinct cognitive and behavioral profile that can aid in the diagnostic process and treatment planning for dementia. Modifiable risk factors for dementia such as nutrition, physical activity, sleep, cognitive and social engagement, and stress provide important avenues for prevention. Neurologists and other health care providers can help patients reduce their risk for dementia by providing them with education about modifiable factors and connecting them to resources to empower them to engage in brain-healthy behavior.

Global trends and hotspots of exercise interventions for mild cognitive impairment: A global bibliometric analysis

BACKGROUND

Exercise interventions for mild cognitive impairment (MCI) have been extensively studied. However, there is no bibliometric study on exercise interventions for MCI. This study aimed to identify the collaborative networks, research hotspots, evolution trends, and future directions.

METHODS

Relevant documents were retrieved from the Web of Science Core Collection database. VOSviewer was used to analyze the co-authorship of the author, countries and institutions, and the keywords co-occurrence. CiteSpace was used to detect burst keywords' research trends.

RESULTS

A total of 569 articles were included and showed an overall increasing trend in annual publications. The most influential subject categories, authors, journals, country, and institutions were "geriatrics gerontology," "Doi, Takehiko and Shimada, Hiroyuki," "Journal of Alzheimer's Disease," USA, and "Veterans Health Administration," respectively. The research hotspots are "effectiveness," "neural mechanism" and "correlation" of exercise interventions, and the emerging trend is "intervention quality."

CONCLUSION

This area is in a rapid development phase, whereby research hotpots are focused and the research trend is clear. The highly productive authors and institutions have made outstanding contributions and the subject categories present an interdisciplinary trend. However, there is weak cooperation between countries and institutions, and a substantial research gap exists between developed and developing countries. Future research may highlight the intervention quality, emphasizing the combination with virtual reality technology.

Mild cognitive impairment predicts the onset of Sarcopenia: a longitudinal analysis from the English Longitudinal Study on Ageing

BACKGROUND

Mild cognitive impairment (MCI) and sarcopenia are two common conditions in older people. It is not widely known if MCI could predict the onset of sarcopenia. Therefore, we aimed to investigate whether MCI could predict the occurrence of sarcopenia in a population of older adults.

METHODS

In the ELSA (English Longitudinal Study on Ageing), MCI was defined as the absence of dementia, preserved functional capacity and low performance in three objective cognitive tests. Sarcopenia was diagnosed as having low handgrip strength and low skeletal muscle mass index during follow-up. The longitudinal association between MCI at the baseline and incident sarcopenia was assessed using a multivariable logistic regression model, reporting the data as adjusted odds ratios (OR) and 95% confidence intervals (95%CI).

RESULTS

3,106 participants (mean age of 63.1 years; 55.3% males) were included. People with MCI reported significantly lower mean handgrip strength values and Skeletal Mass Index (SMI), as well as a higher prevalence of obesity at baseline. At baseline, 729 people had MCI and during the ten years follow-up period, 12.1% of the initial population included had sarcopenia. On multivariate analysis, adjusted for 18 potential confounders, the presence of MCI (OR = 1.236; 95%CI: 1.090-1.596, p = 0.01) significantly predicted the onset of sarcopenia during follow-up.

CONCLUSION

The presence of MCI at baseline was associated with a higher incidence of sarcopenia at ten-years follow-up, demonstrating a likely role of MCI as a predictor of the onset of sarcopenia in older people.

Leisure-Time Physical Activity May Attenuate the Impact of Diabetes on Cognitive Decline in Middle-Aged and Older Adults: Findings From the ELSA-Brasil Study

OBJECTIVE

To assess leisure-time physical activity (LTPA) as a modifier of the diabetes/cognitive decline association in middle-aged and older participants in the Estudo Longitudinal de Saude do Adulto (ELSA-Brasil) study.

RESEARCH DESIGN AND METHODS

ELSA-Brasil is a cohort of 15,105 participants (age 35-74 years) enrolled between 2008 and 2010. We evaluated global cognitive function, summing the scores of six standardized tests evaluating memory and verbal fluency, including the Trail-Making Test, at baseline and follow-up. Incident cognitive impairment was defined as a global cognitive function score at follow-up lower than -1 SD from baseline mean. Participants reporting ≥150 min/week of moderate to vigorous LTPA at baseline were classified as physically active. We assessed the association of LTPA with global cognition change in those with diabetes in the context of our overall sample through multivariable regression models.

RESULTS

Participants' (N = 12,214) mean age at baseline was 51.4 (SD 8.8) years, and 55.5% were women. During a mean follow-up of 8.1 (SD 0.6) years, 9,345 (76.5%) inactive participants and 1,731 (14.1%) participants with diabetes at baseline experienced faster declines in global cognition than those who were active (β = -0.003, -0.004, and -0.002) and those without diabetes (β = -0.004, -0.005, and -0.003), respectively. Diabetes increased the risk of cognitive impairment (hazard ratio [HR] 1.71; 95% Cl 1.22, 2.39) in inactive but not in active adults (HR 1.18; 95% CI 0.73, 1.90). Among participants with diabetes, those who were active showed a delay of 2.73 (95% CI 0.94, 4.51) years in the onset of cognitive impairment.

CONCLUSIONS

In adults living with diabetes, LTPA attenuated the deleterious association between diabetes and cognitive function.

Systematic review and meta-analysis on population attributable fraction for physical inactivity to dementia

INTRODUCTION

The number of cases of dementia attributable to physical inactivity remains unclear due to heterogeneity in physical inactivity definitions and statistical approaches used.

METHODS

Studies that used population-based samples to estimate the population attributable fraction (PAF) of physical inactivity for dementia were included in this review. Weighted PAFs were adjusted for communality among the risk factors (i.e., inactive persons may also share other risk factors) analyzed. Values were reported as percentage (%) of cases of dementia attributable to physical inactivity.

RESULTS

We included 22 studies. The overall impact of physical inactivity, defined by any criteria, on dementia ranged from 6.6% (95% CI: 3.6%, 9.6%; weighted) to 16.6% (95% CI: 14.4%, 18.9%; unweighted). Studies using the WHO criterion for physical inactivity estimated a higher unweighted impact (β = 7.3%; 95% CI: 2.0%, 12.6%) than studies using other criteria.

DISCUSSION

Conservatively, one in 15 cases of dementia may be attributable to physical inactivity, defined by any criteria.

Physical activity for cognitive health promotion: An overview of the underlying neurobiological mechanisms

Physical activity is one of the modifiable factors of cognitive decline and dementia with the strongest evidence. Although many influential reviews have illustrated the neurobiological mechanisms of the cognitive benefits of physical activity, none of them have linked the neurobiological mechanisms to normal exercise physiology to help the readers gain a more advanced, comprehensive understanding of the phenomenon. In this review, we address this issue and provide a synthesis of the literature by focusing on five most studied neurobiological mechanisms. We show that the body's adaptations to enhance exercise performance also benefit the brain and contribute to improved cognition. Specifically, these adaptations include, 1), the release of growth factors that are essential for the development and growth of neurons and for neurogenesis and angiogenesis, 2), the production of lactate that provides energy to the brain and is involved in the synthesis of glutamate and the maintenance of long-term potentiation, 3), the release of anti-inflammatory cytokines that reduce neuroinflammation, 4), the increase in mitochondrial biogenesis and antioxidant enzyme activity that reduce oxidative stress, and 5), the release of neurotransmitters such as dopamine and 5-HT that regulate neurogenesis and modulate cognition. We also discussed several issues relevant for prescribing physical activity, including what intensity and mode of physical activity brings the most cognitive benefits, based on their influence on the above five neurobiological mechanisms. We hope this review helps readers gain a general understanding of the state-of-the-art knowledge on the neurobiological mechanisms of the cognitive benefits of physical activity and guide them in designing new studies to further advance the field.

The Role of Internet Use and Offline Social Engagement in the Health of Chinese Older Adults: Evidence from Nationally Representative Samples

This study investigated the association between internet use as a novel type of social engagement and the health of older adults, and evaluated the role of online versus offline social activities through nationally representative samples. Participants aged ≥ 60 in the datasets from the Chinese sample of the World Value Survey (N_{Sample 1} = 598) and the China Health and Retirement Longitudinal Study (CHARLS, N_{Sample 2} = 9434) were selected. Correlation analysis presented the positive relationships between internet use and self-reported health in both Sample 1 (r = 0.17, p < 0.001) and Sample 2 (r = 0.09, p < 0.001). In addition, the relationships between internet use and both self-reported health and depression (r = -0.14, p < 0.001) were stronger than the correlation between offline social activities and health outcomes in Sample 2. After accounting for the frequency of traditional social activities, regression analysis revealed the relationship between internet use and higher self-reported health (β_{Sample 1} = 0.16, p < 0.001; β_{Sample 2} = 0.04, p < 0.001) and lower depressive symptom scores (β = -0.05, p < 0.001) This research contributes to the existing body of literature on the favorable relationship between social engagement and health outcomes among Chinese older adults. Additionally, it identifies the social benefits of internet use for health promotion among older adults.

Relationship Between Physical Exercise and Cognitive Impairment Among Older Adults with Type 2 Diabetes: Chain Mediating Roles of Sleep Quality and Depression

Objective

Although physical exercise has been shown to boost physical, psychological, and psychiatric conditions in older adults, there is a relative lack of research on the mechanisms involved in this process for older adults with type 2 diabetes mellitus (T2DM). We thus evaluated whether sleep quality and depression mediated the relationship between physical exercise and cognitive impairment in older adults with T2DM by focusing on the exercise-physiology-psychology and psychiatry connection.

Methods

Self-reported data were collected from 2646 older adults with T2DM in Weifang, Shandong, China. Regression and bootstrap analyses were conducted to explore the chain mediator model including physical exercise, cognitive impairment, sleep quality, and depression.

Results

Engaging in physical exercise (coefficient = -0.6858, p < 0.001), high levels of sleep quality (coefficient = -0.3397, p = 0.015), and low levels of depression (coefficient = 0.3866, p < 0.001) were significantly associated with a low level of cognitive impairment. Sleep quality and depression mediated the chain effect between physical exercise and cognitive impairment (total effect = -1.0732, 95% CI [-1.3652, -0.7862]; direct effect = -0.6858, 95% CI [-0.9702, -0.3974]; indirect effect = -0.3875, 95% CI [-0.5369, -0.2521]).

Conclusion

Physical exercise may improve sleep quality in older adults with T2DM, alleviating depression and delaying the development of cognitive impairment. Physical exercise can enhance patients' ability to resist depression and cognitive impairment, and creating comfortable sleep environments can also reinforce the effects of this process. These findings have important implications for promoting healthy aging in older adults with T2DM.

Can habitual tea drinking be an effective approach against age-related neurodegenerative cognitive disorders: A systematic review and meta-analysis of epidemiological evidence

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75-0.88) and 0.69 (95% CIs: 0.61-0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14-1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

Development of a Combined Exercise and Cognitive Stimulation Intervention for People with Mild Cognitive Impairment-Designing the MEMO_MOVE PROGRAM

Dementia patients are at high risk for the decline of both physical and cognitive capacities, resulting in an increased risk of the loss of autonomy. Exercise is regarded as a non-pharmacological therapy for dementia, considering the potential benefits of preventing cognitive decline and improving physical fitness. In this paper, we aim to describe the different design stages for an exercise program combined with cognitive stimulation for a population with mild cognitive impairment, i.e., the MEMO_MOVE program.

METHODS

The intervention design followed the Medical Research Council's guidelines for complex interventions and was structured according to the six steps in quality intervention development (6SQuID). The intervention was described considering the Template for Intervention Description and Replication (TIDieR). In order to establish the intervention characteristics, a literature review was conducted to collate and analyze previous work, which provided a summary the type of exercise that should be implemented among this population.

RESULTS

The MEMO_MOVE program was structured and described, regarding (i) inclusion of a cognitive stimulation component; (ii) the kind of cognitive stimulation; and (iii) the type of exercise, duration, frequency, intensity, and program length.

CONCLUSIONS

A systematic step-by-step process design was followed to create a specific intervention to promote physical fitness and cognitive stimulation in individuals with mild dementia.

The impact of physical activity on blood inflammatory cytokines and neuroprotective factors in individuals with mild cognitive impairment: a systematic review and meta-analysis of randomized-controlled trials

BACKGROUND

Accumulated evidence has proved that both neuroinflammation and neuroprotection existing at the stage of mild cognitive impairment (MCI) may mediate its progression, which can conversely be modulated by physical activity (PA). However, further research is needed to clarify which factors are involved in that process.

OBJECTIVES

To identify the impact of PA on inflammatory cytokines and neuroprotective factors in individuals with MCI.

METHODS

Four databases [PubMed, Cochrane Library, Cochrane Library (Trials), Embase and Web of Science Core Collection] were searched from their inception to October 2021 for randomized-controlled trials (RCTs) assessing the biochemical effect of PA on biomarkers in participants with MCI. Pooled effect size was calculated by the standardized mean difference (SMD).

RESULTS

A total of 13 RCTs involving 514 participants by reporting 8 inflammatory cytokines [tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, -6, -8, -10, -15, C-reactive protein (CRP) and interferon-γ (IFN-γ) and 5 neuroprotective factors (brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-1), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), irisin] were included. The meta-analysis showed that PA had positive effects on decreasing TNF-α (SMD =  - 0.32, 95% CI - 0.58 to 0.07, p = 0.01; I² = 32%) and CRP (SMD = - 0.68, 95% CI - 1.05 to 0.32, p = 0.0002; I² = 18%), while significantly improving BDNF (SMD = 0.32, 95% CI 0.09-0.56, p = 0.007; I² = 42%) and IGF-1 (SMD = 0.42, 95% CI 0.03-0.81, p = 0.03; I² = 0%).

CONCLUSION

PA had a certain effect on inhibiting inflammatory cytokines but promoting neuroprotective factors in individuals with MCI which may provide a possible explanation for the potential molecular mechanism of PA on cognitive improvement.

Exercise Dosage in Reducing the Risk of Dementia Development: Mode, Duration, and Intensity-A Narrative Review

Senile dementia, also known as dementia, is the mental deterioration which is associated with aging. It is characterized by a decrease in cognitive abilities, inability to concentrate, and especially the loss of higher cerebral cortex function, including memory, judgment, abstract thinking, and other loss of personality, even behavior changes. As a matter of fact, dementia is the deterioration of mental and intellectual functions caused by brain diseases in adults when they are mature, which affects the comprehensive performance of life and work ability. Most dementia cases are caused by Alzheimer’s disease (AD) and multiple infarct dementia (vascular dementia, multi-infarct dementia). Alzheimer’s disease is characterized by atrophy, shedding, and degenerative alterations in brain cells, and its occurrence is linked to age. The fraction of the population with dementia is smaller before the age of 65, and it increases after the age of 65. Since women live longer than men, the proportion of women with Alzheimer’s disease is higher. Multiple infarct dementia is caused by a cerebral infarction, which disrupts blood supply in multiple locations and impairs cerebral cortex function. Researchers worldwide are investigating ways to prevent Alzheimer’s disease; however, currently, there are no definitive answers for Alzheimer’s prevention. Even so, research has shown that we can take steps to reduce the risk of developing it. Prospective studies have found that even light to moderate physical activity can lower the risk of dementia and Alzheimer’s disease. Exercise has been proposed as a potential lifestyle intervention to help reduce the occurrence of dementia and Alzheimer’s disease. Various workout modes will be introduced based on various physical conditions. In general, frequent exercise for 6–8 weeks lessens the risk of dementia development.