The Impact of Depression on the Development of Mild Cognitive Impairment over 3 Years of Follow-Up: A Population-Based Study

Exploring the Reciprocal Relationship between Depressive Symptoms and Cognitive Function among Chinese Older Adults

(1) Objectives: This study aims to investigate the bidirectional relationship between depressive symptoms and cognitive function among older adults in China, addressing a research gap in the context of developing nations. (2) Methods: A total of 3813 adults aged 60 and older participating in 2013, 2015, and 2018 waves of the China Health and Retirement Longitudinal Study (CHARLS) were included. A fixed-effects model and cross-lagged panel model (CLPM) was utilized. (3) Results: First, the results indicated that a significant negative correlation existed between depressive symptoms and cognitive function in older adults during the study period (β = -0.084, p < 0.001). Second, after controlling for unobserved confounding factors, the deterioration and improvement of depressive symptoms still significantly affected cognitive function (β = -0.055, p < 0.001). Third, using the cross-lagged panel model, we observed a reciprocal relationship between depressive symptoms (Dep) and cognitive function (Cog) among Chinese older adults (Dep2013 → Cog2015, β = -0.025, p < 0.01; Dep2015 → Cog2018, β = -0.028, p < 0.001; Cog2013 → Dep2015, β = -0.079, p < 0.01; Cog2015 → Dep2018, β = -0.085, p < 0.01). (4) Discussion: The reciprocal relationship between depressive symptoms and cognitive functioning in older adults emphasizes the need for integrated public health policies and clinical interventions, to develop comprehensive intervention strategies that simultaneously address depressive symptoms and cognitive decline.

Sensory impairment and cognitive function among older adults in China: The mediating roles of anxiety and depressive symptoms

OBJECTIVES

Through a cross-sectional study, we explored the association between sensory impairment and cognitive function in Chinese older adults, and tested the mediating roles of anxiety and depressive symptoms between this relationship.

METHODS

Based on the 2018 Chinese Longitudinal Healthy Longevity Survey, a total of 10,895 older adults aged 65 and above were selected as samples for research. Anxiety, depressive symptoms and cognitive function were evaluated by the Generalized Anxiety Disorder, the Center for Epidemiologic Studies Depression (CES-D10) and the Chinese version of modified Mini-Mental State Examination scales, respectively. Sensory impairment was assessed from self-reported vision and hearing functions. Multiple linear regression and SPSS Macro PROCESS were used for statistical analysis.

RESULTS

Compared with no sensory impairment, vision impairment (B = -1.012, 95%CI: -1.206, -0.818), hearing impairment (B = -2.683, 95%CI: -2.980, -2.386) and dual sensory impairment (B = -6.302, 95%CI: -6.585, -6.020) have a significant association with cognitive function in older adults, respectively. Anxiety and depressive symptoms not only acted as independent mediators, but also played sequential mediating effects on the relationship between sensory impairment and cognitive function.

CONCLUSIONS

Greater attention should be paid to anxiety and depressive symptoms of older adults with sensory impairment, which might be beneficial to maintain cognitive function.

Fluctuation of depressive symptoms in cognitively unimpaired participants and the risk of mild cognitive impairment 5 years later: Results of the Heinz Nixdorf Recall study

BACKGROUND

Depression might be an independent risk factor for cognitive decline, a prodromal dementia symptom or a reaction to cognitive/functional impairment.

OBJECTIVE

To investigate the association between (1) depressive symptoms and (2) depressive symptom patterns over 13 years with incident mild cognitive impairment (MCI) 5 years later.

MATERIALS AND METHODS

We included 724/823 cognitively unimpaired men/women who participated in the population-based Heinz Nixdorf Recall study (t1: 2005-2008, ø62.9 years; t2: 2010-2015, ø68.1 years). Depressive symptoms were assessed in the study center and during six postal follow-ups using the short form of the Center for Epidemiologic Studies Depression Scale (CES-D). Relative risks (RR; 95% confidence intervals) for MCI at t2 (men/women: 71/76) were estimated for CES-D at t1 (linear and dichotomized at ≥17, cut-off for clinically relevant depressive symptoms) and CES-D fluctuations over 13 years (stable low, large fluctuations, stable high/stable around cut-off) using log-linear regression models with Poisson working likelihood adjusted for age, sex, education, diabetes mellitus, coronary heart disease, and stroke.

RESULTS

Fully adjusted risk for MCI at t2 (per CES-D point increase at t1) was elevated for the total cohort (1.053, 1.031-1.076), men (1.046, 1.012-1.081), and women (1.059, 1.029-1.090). Applying the dichotomized CES-D, risk for MCI was substantially increased for the total cohort [2.22 (1.38-3.58)] and in women [2.59 (1.46-4.58)]. Large CES-D fluctuations and stable high/stable around cut-off were associated with increased RR for MCI in the total cohort and in women compared to stable low symptoms.

CONCLUSION

Depressive symptoms predicted MCI in cognitively unimpaired participants of our population-based study. Adequate treatment of depression may therefore contribute to the maintenance of normal cognition and delay dementia onset.

Depressive Symptoms and Cognitive Decline Among Chinese Rural Elderly Individuals: A Longitudinal Study With 2-Year Follow-Up

Background

Depressive symptoms and mild cognitive impairment (MCI) are highly prevalent in rural China. The study aimed to investigate the longitudinal associations between changes in depressive symptoms and cognitive decline and MCI incidence among Chinese rural elderly individuals.

Methods

A 2-year follow-up study was conducted among 1,477 participants from the Anhui Healthy Longevity Survey (AHLS). Depressive symptoms were assessed by the 9-item Patient Health Questionnaire (PHQ-9), and cognitive status was evaluated by the Mini Mental State Examination (MMSE). Multivariable linear regression and logistic regression were employed.

Results

Every 1-unit PHQ-9 score increase was significantly associated with more cognitive decline (β = 0.157, 95% CI: 0.092, 0.221, p &lt; 0.001) and a higher risk of MCI incidence (OR = 1.063, 95% CI: 1.025, 1.103, p = 0.001). The participants who experienced worsening of depression symptoms had a larger decline in the 2-year MMSE score (β = 0.650, 95% CI: 0.039, 1.261, p = 0.037) and elevated risks of incident MCI (OR = 1.573, 95% CI: 1.113, 2.223, p = 0.010).

Limitations

Screening tools rather than standard diagnostic procedures were used in the study. Moreover, the long-term associations still need further exploration since the follow-up time was short.

Conclusions

Increased depressive symptoms were associated with more cognitive decline and higher risks of incident MCI among Chinese rural residents.

Happiness, depression, physical activity and cognition among the middle and old-aged population in China: a conditional process analysis

Background

Happiness is one variable of subjective well-being, which has been increasingly shown to have protective effects on health. Although the association between happiness and cognition has been established, the mechanism by which happiness leads to cognition remains unclear. Since happiness, depression, and physical activity may all be related to cognition, and happiness is related to depression and physical activity, this study explored the effect of depression and physical activity on the relationship between happiness and cognition among middle and old-aged individuals in China.

Methods

Data on 14,344 participants above 45 years of age were obtained from the 2018 China Family Panel Studies survey. A multiple linear regression analysis was performed to identify the correlation factors of cognition. The conditional process analysis was used to assess the mediatory effect of depression and physical activity on the relationship between happiness and cognition.

Results

Residence, age, sex, income level, social status, smoking, napping, reading, education, exercise times, satisfaction, happiness, and depression had associations with cognition. When other variables were held constant, cognition score increased by 0.029 standard deviation(SD) for every 1 SD increased in happiness. Mediation analysis showed that happiness had a significant positive total effect on cognition. The direct effect of happiness was significant and accounted for 57.86% of the total effect. The mediatory effect of depression (path of happiness→depression→cognition) accounted for 38.31% of the total effect, whereas that of physical activity (path of happiness→exercise times→cognition) accounted for 3.02% of the total effect.

Conclusion

Happiness has a positive correlation with cognitive function, and depression and physical activity play mediatory roles in this association. Effective interventions to improve happiness levels of middle and old-aged population will not only improve their subjective well-being but also improve their cognitive function, which carries great potential for reducing public health burdens related to cognitive aging.

Depression and bone loss as risk factors for cognitive decline: A systematic review and meta-analysis

BACKGROUND

Depression is linked to Alzheimer's disease (AD) but it is unclear whether depression is also associated with cognitive decline in the preclinical phase and mild cognitive impairment (MCI). Previous meta-analyses have only investigated AD as an outcome without accounting for individuals showing cognitive decline that does not meet the diagnostic criteria for AD. Other potentially modifiable risk factors such as bone loss have also been less explored and there remains uncertainty around their temporal relationship with cognitive decline.

AIMS

To conduct a systematic review and meta-analysis investigating depression and bone loss as risk factors for subsequent cognitive decline.

METHODS

A comprehensive search strategy was developed and applied using four databases; MEDLINE Complete, Embase, PsycINFO and CINAHL Complete. The pooled summary effects were estimated as odds ratios with 95% confidence intervals using a random-effects model. The study protocol was registered with PROSPERO (ID: CRD42020159369).

RESULTS

A total of 75 longitudinal cohort studies were identified for meta-analysis, of which 70 examined the impact of depression on cognitive decline and five examined the impact of bone loss. Prior exposure to depression was found to be associated with cognitive score reduction (OR 1.33 95% CI 1.17, 1.51), MCI incidence (OR 1.52 95% CI 1.28, 1.79) and AD incidence (OR 1.79 95% CI 1.46, 2.2). Bone loss was also associated with the incidence of AD (OR=1.81 95% CI 1.28, 2.55).

CONCLUSIONS

Overall, the results support the hypothesis that depression is associated with subsequent cognitive decline. Bone loss was also found to be associated with AD incidence; however, due to the small number of studies, the results should be viewed with caution.

Association between functional disability and depressive symptoms among older adults in rural China: a cross-sectional study

Objectives

The aim of this study was to explore the relationship between functional disability and depressive symptoms, focusing on whether an interaction exists between functional disability, demographic characteristics and depressive symptoms among older adults in rural China.

Design

A cross-sectional study using multistage, stratified random sampling.

Setting

Data from 18 villages in Anhui Province of China between January to July 2018.

Participants

3491 Chinese participants aged 60 and over.

Primary and secondary outcome measures

The 30-item Geriatric Depression Scale and WHO Disability Assessment Schedule 2.0 were used to evaluate depressive symptoms and functional disability, respectively. Data were analysed using SPSS statistics V.25.0 program with χ2 test, Mann-Whitney U test, binary logistic regression analysis and classification and regression tree (CART) model.

Results

The prevalence of depressive symptoms in 3336 interviewed older people was 52.94%. After adjustment, subjects who had problems in mobility domain (adjusted OR (AOR) 1.842, 95% CI 1.503 to 2.258), getting along domain (AOR 1.616, 95% CI 1.299 to 2.010), life activities domain (AOR 1.683, 95% CI 1.370 to 2.066) and participation domain (AOR 3.499, 95% CI 2.385 to 4.987) had an increased depressive symptoms risk. However, cognition domain (AOR 0.785, 95% CI 0.647 to 0.953) negatively correlated with depressive symptoms. Additionally, the CART model showed that those who had problems in mobility domain, getting along domain and were unemployed, the possibility of having depressive symptoms was the highest.

Conclusions

More attention should be paid to unemployed older adults, and those with problems in participation, life activities, getting along and mobility and no problems in cognition to maintain a good psychological state.

Prevalence of cognitive impairment in Chinese older inpatients and its relationship with 1-year adverse health outcomes: a multi-center cohort study

BACKGROUND

Previous studies on the relationship between cognitive impairment and adverse outcomes among geriatric inpatients are not representative of older inpatients in China because of insufficient sample sizes or single-center study designs. The purpose of our study was to examine the prevalence of cognitive impairment and the relationship between cognitive impairment and 1-year adverse health outcomes in older inpatients.

METHODS

This study was a large-scale multi-center cohort study conducted from October 2018 to February 2020. Six tertiary hospitals across China were selected using a two-stage cluster sampling method, and eligible older inpatients were selected for the baseline survey and follow-up. The Mini Cognitive Scale and the FRAIL scale were used to screen for cognitive impairment and frailty, respectively. The EuroQol-5 Dimension-5 Level questionnaire was used to assess health-related quality of life (HRQoL). We used a generalized estimating model to evaluate the relationship between cognitive impairment and adverse outcomes.

RESULTS

The study included 5008 men (58.02%) and 3623 women (41.98%), and 70.64% were aged 65-75 years, and 26.27% were aged 75-85 years. Cognitive impairment was observed in 1756 patients (20.35%). There were significant differences between participants with cognitive impairment and those with normal cognitive function for age, gender, surgery status, frailty, depression, handgrip strength and so on. After adjusting for multiple covariates, compared with patients with normal cognitive function, the odds ratio for 1-year mortality was 1.216 (95% confidence interval [CI]: 1.076-1.375) and for 1-year incidence of frailty was 1.195 (95% CI: 1.037-1.376) in patients with cognitive impairment. Similarly, the regression coefficient of 1-year HRQoL was - 0.013 (95% CI: - 0.024-- 0.002). In the stratified analysis, risk of adverse outcome within 1 year was higher in older patients with cognitive impairment aged over 75 years than those aged 65-74 years.

CONCLUSIONS

We revealed that cognitive impairment was highly correlated with occurrence of 1-year adverse health outcomes (death, frailty, and decreased HRQoL) in older inpatients, which provides a basis for formulating effective intervention measures.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800017682 , registered 09 August 2018.

Depressive symptoms and cognitive impairment: A 10-year follow-up study from the Survey of Health, Ageing and Retirement in Europe

Background

Depressive symptoms and cognitive impairment often coexisted in the elderly. This study investigates the effect of late-life depressive symptoms on risk of mild cognitive impairment (MCI).

Methods

A total of 14,231 dementia- and MCI free participants aged 60+ from the Survey of Health, Ageing, and Retirement in Europe were followed-up for 10 years to detect incident MCI. MCI was defined as 1.5 standard deviation (SD) below the mean of the standardized global cognition score. Depressive symptoms were assessed by a 12-item Europe-depression scale (EURO-D). Severity of depressive symptoms was grouped as: no/minimal (score 0–3), moderate (score 4–5), and severe (score 6–12). Significant depressive symptoms (SDSs) were defined as EURO-D score ≥ 4.

Results

During an average of 8.2 (SD = 2.4)-year follow-up, 1,352 (9.50%) incident MCI cases were identified. SDSs were related to higher MCI risk (hazard ratio [HR] = 1.26, 95% confidence intervals [CI]: 1.10–1.44) in total population, individuals aged 70+ (HR = 1.35, 95% CI: 1.14–1.61) and women (HR = 1.28, 95% CI: 1.08–1.51) in Cox proportional hazard model adjusting for confounders. In addition, there was a dose–response association between the severity of depressive symptoms and MCI incidence in total population, people aged ≥70 years and women (p-trend <0.001).

Conclusions

Significant depressive symptoms were associated with higher incidence of MCI in a dose–response fashion, especially among people aged 70+ years and women. Treating depressive symptoms targeting older population and women may be effective in preventing MCI.

Reading activity prevents long-term decline in cognitive function in older people: evidence from a 14-year longitudinal study

OBJECTIVE

This study examined the effect of daily life reading activity on the risk of cognitive decline and whether the effect differs regarding education levels.

DESIGN

A longitudinal study with 6-, 10-, and 14-year follow-up.

SETTING

Face-to-face interviews with structured questionnaires at home.

PARTICIPANTS

A representative sample of 1,962 Taiwanese community-dwelling older persons aged 64 and above, followed up in four waves of surveys over 14 years.

MEASUREMENTS

Baseline reading frequencies were measured based on a scale of leisure activity. The Short Portable Mental Status Questionnaire was used to measure cognitive performance. We performed logistic regression to assess associations between baseline reading and later cognitive decline. Interaction terms between reading and education were to compare the reading effects on cognitive decline at different education levels.

RESULTS

After adjusting for covariates, those with higher reading frequencies (≥1 time a week) were less likely to have cognitive decline at 6-year (adjusted odds ratio [AOR]: 0.54; 95% confidence interval [CI]: 0.34-0.86), 10-year (AOR: 0.58, 95% CI: 0.37-0.92), and 14-year (AOR: 0.54, 95% CI: 0.34-0.86); in a 14-year follow-up, a reduced risk of cognitive decline was observed among older people with higher reading frequencies versus lower ones at all educational levels.

CONCLUSIONS

Reading was protective of cognitive function in later life. Frequent reading activities were associated with a reduced risk of cognitive decline for older adults at all levels of education in the long term.

Predictors of Quality of Life among Older People with Mild Cognitive Impairment Attending Urban Primary Care Clinics

OBJECTIVES

To study the prevalence of Mild Cognitive Impairment (MCI) among older people attending primary care clinics and its predictors of QOL.

METHODS

A cross-sectional study was conducted at two primary care clinics in Kuala Lumpur, Malaysia, recruiting 271 participants by utilizing the universal sampling method. Every patient who attended both the clinics during the study period and met the inclusion and exclusion criteria were approached and briefed about the study. Patients who gave consent were recruited as study participants. Information on sociodemographic, medical condition, and lifestyle behaviors were obtained. The Montreal Cognitive Assessment (MoCA) was used to screen for MCI at a score < 23. The World Health Organization Quality of Life-BREF (WHOQOL-BREF) questionnaire was used to evaluate QOL.

RESULTS

Prevalence of MCI was 27.3%. Lower QOL scores were found in the physical (67.3 ± 1.4), psychological (67.3 ± 1.4), social (66.9 ± 1.6) and environmental (71.3 ± 1.3) domains among participants with MCI. Among them, predictors of QOL were depression in the physical domain, age and stroke in the psychological domain, presence of other types of disorders in the social domain and diabetes and stroke in the environmental domain.

CONCLUSIONS

MCI was prevalent among study participants and were associated with poorer QOL in all domains of QOL. A better understanding of predictors of QOL in older people with MCI is deemed important.

CLINICAL IMPLICATION

Routine cognitive screening at primary care clinics will facilitate early recognition of MCI and facilitates referral to memory clinics for further assessment and treatment.

Structural Model for Estimating the Influence of Healthy Lifestyle on Episodic Memory in Adults with Subjective Memory Complaints

The aim of this study is to examine the relationships between a healthy lifestyle and episodic memory among adults with subjective memory complaints (SMCs). We proposed a structure equation model to study the association between a healthy lifestyle and episodic memory with an investigation covering 309 participants over 50 years old with SMCs. The model showed a good fit after being adjusted (p = 0.054, goodness of fit index = 0.981, adjusted goodness of fit index = 0.956, comparative fit index = 0.981, and root mean square error of approximation = 0.049): a healthy lifestyle has a direct positive effect on episodic memory among adults with SMCs (β = 0.60). The research model provides possible guidelines for medical staff to prevent the cognitive function decline in the risk population of Alzheimer's disease.

Associations Between a History of Depression and Cognitive Performance Among Older Adults in Shandong, China

This study investigates the relationships between depression and cognitive performance among older adults living in Shandong province. Data were derived from the World Health Organization's Study on global AGEing and adult health (WHO-SAGE) China Wave 1 aged 50 and over residing in Shandong province (n = 1926). Cognitive performance was assessed by overall cognitive score. Data were analysed by multivariate linear regression. In rural Shandong, having a history of depression (- 4.0; p < 0.001), female (- 9.3; p < 0.001), and poor household wealth (- 8.9; p < 0.001) and primary level of education (- 6.4; p < 0.001) were main factors associated with their poor cognitive performance. Notably, in urban Shandong, lowest household wealth (- 12.5; p < 0.001) and not having health insurance (- 9.7; p < 0.001) were significant predictors of adverse cognitive performance. Findings could help inform policy in monitoring depressive symptoms and cognitive performance among older adults in China.

Happiness and Cognitive Impairment Among Older Adults: Investigating the Mediational Roles of Disability, Depression, Social Contact Frequency, and Loneliness

Background: Understanding the lower level of happiness among older adults with cognitive impairment has been a largely neglected issue. This study (1) reports on the level of happiness among older adults in Singapore and (2) examines the potential mediating roles of depression, disability, social contact frequency, and loneliness in the relationship between cognitive scores and happiness. Methods: Data for this study were extracted from the Well-being of the Singapore Elderly (WiSE) study: a cross-sectional; comprehensive single-phase survey conducted among Singapore citizens and permanent residents that were aged 60 years and above (n = 2565). The Geriatric Mental State examination (GMS) was administered to the participants. Questions pertaining to socio-demographic characteristics; happiness; loneliness; social contact; depression; and, disability were utilized in this study. Logistic regression analyses and mediation analyses were used to explore the correlates of happiness and potential mediating factors. Results: Overall, 96.2% of older adults in Singapore reported feeling either fairly happy or very happy. In the regression analysis, individuals of Malay descent, those who were married/cohabiting, or had higher education levels were more likely to report feeling happy. After controlling for socio-demographic factors, higher cognitive scores were associated with higher odds of reporting happiness. We found that the positive association between cognition and happiness was fully mediated by disability, depression, loneliness, and frequency of contact with friends. Conclusion: The majority of the older adult population reported feeling fairly or very happy. While cognitive impairment has shown limited reversibility in past studies, unhappiness among older adults with cognitive impairment might be potentially mitigated through interventions addressing accompanying issues of social isolation, disability, and depression

Associations between handgrip strength and mild cognitive impairment in middle-aged and older adults in six low- and middle-income countries

OBJECTIVES

A number of small-scale, single-country studies have suggested that muscular weakness may be a biomarker for cognitive health, mild cognitive impairment (MCI), and dementia. However, multinational, representative studies are lacking, particularly from low- and middle-income countries (LMICs). Thus, we assessed the association between muscular strength (measured by maximal handgrip) and MCI in six LMICs (China, Ghana, India, Mexico, Russia, and South Africa), using nationally representative data.

METHODS

Cross-sectional, community-based data on individuals aged 50 years or older from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. MCI was defined according to the National Institute on Aging-Alzheimer's Association criteria. Weak handgrip strength was defined as less than 30 kg for men and less than 20 kg for women using the average value of two handgrip measurements of the dominant hand. Multivariable logistic regression analysis was conducted to assess the association between muscular strength and MCI.

RESULTS

A total of 32 715 participants were included (mean age 62 ± SD 15.6 y and 51.7% female). The prevalence of MCI and weak handgrip strength was 15.3% (95% CI, 14.4%-16.3%) and 46.5% (95% CI, 43.6%-49.5%), respectively. After adjustment for potential confounders, weak handgrip strength was associated with 1.41 (95% CI, 1.23-1.61) times higher odds for MCI. The corresponding figures for those aged 50 to 64 years and 65 years or older were 1.35 (95% CI, 1.14-1.60) and 1.54 (95% CI, 1.27-1.86), respectively.

CONCLUSIONS

Muscular weakness may provide a clinically useful indicator of MCI risk. Increasing our understanding of the connection between muscular and cognitive function could ultimately lead to the development and broader implementation of resistance training interventions targeting both physical and cognitive health.

Food Insecurity Is Associated with Mild Cognitive Impairment among Middle-Aged and Older Adults in South Africa: Findings from a Nationally Representative Survey

There are no studies on the association between food insecurity and mild cognitive impairment (MCI). Thus, cross-sectional, community-based data on individuals aged ≥50 years from the World Health Organization’s Study on Global AGEing and Adult Health (SAGE) conducted in South Africa (2007–2008) were analyzed to assess this association. The definition of MCI was based on the National Institute on Ageing-Alzheimer’s Association criteria. Past 12-month food insecurity was assessed with two questions on frequency of eating less and hunger due to lack of food. Multivariable logistic regression analysis was conducted. The sample consisted of 3,672 individuals aged ≥50 years [mean (SD) age 61.4 (18.3); 56% females]. The prevalence of MCI was 8.5%, while 11.0% and 20.8% experienced moderate and severe food insecurity, respectively. After adjustment for potential confounders, moderate and severe food insecurity were associated with 2.82 (95%CI = 1.65–4.84) and 2.51 (95%CI = 1.63–3.87) times higher odds for MCI compared with no food insecurity, respectively. The OR for those aged ≥65 years with severe food insecurity was particularly high (OR = 3.87; 95%CI = 2.20–6.81). In conclusion, food insecurity was strongly associated with MCI among South African older adults. Future longitudinal research is required to assess whether addressing food insecurity may reduce risk of MCI and subsequent dementia.

Mind the gaps: What we don't know about cognitive impairment in essential tremor

INTRODUCTION

Although the hallmark feature of essential tremor (ET) is tremor, there is growing appreciation that cognitive impairment also occurs, including increased prevalence of mild cognitive impairment (MCI) and increased prevalence and incidence of dementia. With emerging knowledge of ET-cognitive impairment, come fundamental questions regarding its course, bases, predictors and clinical outcomes. Studies in the general population and in Parkinson's disease (PD), a related movement disorder, offer a starting point from which to begin filling these clinically important knowledge gaps.

METHODS

A PubMed search (June 2018) identified articles for this review.

RESULTS

Much of our knowledge of cognitive impairment in ET is of the static condition (e.g., prevalence of cognitive impairment in ET), with nearly no information on its bases, predictors and dynamics (i.e., course, and clinical outcomes). In PD, where such data have been published, rates of cognitive decline and conversion to MCI/dementia are higher than in the general population. Predictors of cognitive change in PD and the general population have also been identified, yet they only partially overlap one another.

CONCLUSION

The predictors and dynamics of cognitive impairment have been investigated fairly extensively in the general population, to a somewhat lesser extent in PD, and are emerging only now in ET. We suggest that longitudinal studies specific to ET are needed, and we outline variables to be considered in these investigations. Increased knowledge of ET-cognitive impairment will facilitate meaningful counseling of patients and their families.

Psychotic experiences and subjective cognitive complaints among 224 842 people in 48 low- and middle-income countries

AIMS

Cognitive deficits are an important factor in the pathogenesis of psychosis. Subjective cognitive complaints (SCCs) are often considered to be a precursor of objective cognitive deficits, but there are no studies specifically on SCC and psychotic experiences (PE). Thus, we assessed the association between SCC and PE using data from 48 low- and middle-income countries.

METHODS

Community-based cross-sectional data of the World Health Survey were analysed. Two questions on subjective memory and learning complaints in the past 30 days were used to create a SCC scale ranging from 0 to 10 with higher scores representing more severe SCC. The Composite International Diagnostic Interview was used to identify past 12-month PE. Multivariable logistic regression and mediation analyses were performed.

RESULTS

The final sample consisted of 224 842 adults aged ⩾18 years [mean (SD) age 38.3 (16.0) years; 49.3% males]. After adjustment for sociodemographic factors, a one-unit increase in the SCC scale was associated with a 1.17 (95% CI 1.16-1.18) times higher odds for PE in the overall sample, with this association being more pronounced in younger individuals: age 18-44 years OR = 1.19 (95% CI 1.17-1.20); 45-64 years OR = 1.15 (95% CI 1.12-1.17); ⩾65 years OR = 1.14 (95% CI 1.09-1.19). Collectively, other mental health conditions (perceived stress, depression, anxiety, sleep problems) explained 43.4% of this association, and chronic physical conditions partially explained the association but to a lesser extent (11.8%).

CONCLUSIONS

SCC were associated with PE. Future longitudinal studies are needed to understand temporal associations and causal inferences, while the utility of SCC as a risk marker for psychosis especially for young adults should be scrutinised.

Perceived Stress and Mild Cognitive Impairment among 32,715 Community-Dwelling Older Adults across Six Low- and Middle-Income Countries

BACKGROUND

Perceived stress may be a modifiable risk factor for mild cognitive impairment (MCI) and ultimately dementia, but studies on this topic from low- and middle-income countries (LMICs) are lacking.

OBJECTIVE

We assessed the association between perceived stress and MCI in six LMICs (China, Ghana, India, Mexico, Russia, and South Africa) using nationally representative data.

METHODS

Cross-sectional, community-based data on individuals aged ≥50 years from the World Health Organization's Study on Global Ageing and Adult Health were analyzed. The definition of MCI was based on the National Institute on Ageing-Alzheimer's Association criteria. A perceived stress score (range 0 [lowest stress] to 10 [highest stress]) was computed based on two questions from the Perceived Stress Scale. Multivariable logistic regression analysis was conducted to assess the as-sociation between perceived stress and MCI.

RESULTS

The mean (SD) age of the 32,715 participants was 62.1 (15.6) years and 51.7% were females. After adjustment for potential confounders including depression, in the overall sample, a one-unit increase in the perceived stress score was associated with a 1.14 (95% CI = 1.11-1.18) times higher odds for MCI. The association was similar among those aged 50-64 and ≥65 years. Countrywise analysis showed that there was a moderate level of between-country heterogeneity in this association (I2 = 59.4%), with the strongest association observed in Russia (OR = 1.33, 95% CI = 1.15-1.55).

CONCLUSION

If our study results are confirmed in prospective studies, addressing perceived stress may have an impact in reducing the risk for MCI and subsequent dementia in LMICs.

Chronic Physical Conditions, Multimorbidity, and Mild Cognitive Impairment in Low- and Middle-Income Countries

OBJECTIVES

To assess the association between chronic physical conditions and multimorbidity and mild cognitive impairment (MCI) in low- and middle-income countries (LMICs).

DESIGN

Nationally representative, cross-sectional, community-based study.

SETTING

Six countries that participated in the World Health Organization Study on Global Ageing and Adult Health.

PARTICIPANTS

Individuals aged 50 and older (N=32,715; mean age 62.1 ± 15.6; 51.7% female).

MEASUREMENTS

The definition of MCI was based on the recommendations of the National Institute on Ageing and Alzheimer's Association. Ten chronic conditions were assessed (angina pectoris, arthritis, asthma, cataract, chronic lung disease, diabetes mellitus, edentulism, hearing problems, hypertension, stroke). Multivariable logistic regression analysis was conducted to assess the association between chronic physical conditions, multimorbidity (≥2 chronic conditions), and MCI.

RESULTS

The prevalence of multimorbidity was 49.8% (95% confidence interval (CI)=48.1-51.5%) and of MCI was 15.3% (95% CI=14.4-16.3%). After adjustment for potential confounders, edentulism (odds ratio (OR)=1.24), arthritis (OR=1.24), chronic lung disease (OR=1.29), cataract (OR=1.33), stroke (OR=1.94), hearing problems (OR=2.27), and multimorbidity (OR=1.40) were significantly associated with MCI. There was a gradual increase in the likelihood of MCI (1 condition: OR=1.21, 95% CI=1.03-1.42; ≥4 conditions: OR=2.07, 95% CI=1.70-2.52).

CONCLUSION

These results highlight the need to investigate the underlying mechanisms linking chronic conditions and MCI and whether prevention or treatment of chronic conditions or multimorbidity can reduce the onset of cognitive decline and subsequent dementia, especially in LMICs.

Physical activity correlates in people with mild cognitive impairment: findings from six low- and middle-income countries

OBJECTIVES

Despite promising research showing that physical activity (PA) might improve cognitive functioning in people with mild cognitive impairment (MCI), people with MCI are less physically active compared with the general population. Therefore, the aim of this study was to assess PA correlates among community-dwelling older people with MCI in six low- and middle-income countries.

DESIGN

Cross-sectional data from the World Health Organization's Study on Global Ageing and Adult Health were analysed.

METHODS

PA level was assessed by the Global Physical Activity Questionnaire. 4854 participants with MCI (mean age 64.4 years; 55.1% females) were grouped into those who do and do not (low PA) meet the 150 min of moderate-to-vigorous PA per week recommendation. Associations between PA and the correlates were examined using multivariable logistic regressions.

RESULTS

The prevalence of low PA was 27.4% (95% confidence interval = 25.0-30.0). In the multivariable analysis, older age and unemployment were the only sociodemographic correlates of low PA. The significant positive correlates of low PA in other domains included depression, being underweight, obesity, asthma, chronic lung disease, hearing problems, visual impairment, slow gait, weak grip strength, poor self-rated health, and lower levels of social cohesion.

CONCLUSIONS

The current data illustrate that a number of sociodemographic and health factors are associated with PA levels among older people with MCI. The promotion of social cohesion may increase the efficacy of public health initiatives while from a health care perspective, somatic co-morbidities, muscle strength and slow gait need to be considered when activating those at risk for dementia.

Mild cognitive impairment and physical activity in the general population: Findings from six low- and middle-income countries

INTRODUCTION

Despite the beneficial effects of physical activity (PA) for people with mild cognitive impairment (MCI) on cognition and the acknowledgement that MCI is a critical period for intervening to prevent dementia, little is known about the actual PA levels in people with MCI. This study investigates the relationship between MCI and compliance with PA recommendations.

METHODS

Cross-sectional data from the World Health Organization's Study on Global Ageing and Adult Health (China, Ghana, India, Mexico, Russia, South Africa) (n=32,715; mean age=62.1±SD 15.6years; 51.7% female) were analyzed. MCI was ascertained based on the National Institute on Aging-Alzheimer's Association recommendations. PA level was assessed by the Global Physical Activity Questionnaire. Participants were grouped into those who do and do not meet the 150min of moderate-to-vigorous PA/week recommendation. Associations between PA and MCI were examined using multivariable logistic regressions.

RESULTS

The overall prevalence [95%CI] of MCI and low PA were 15.3% [14.4%-16.3%] and 22.4% [21.1%-23.7%] respectively. In the model adjusted for sociodemographic factors, MCI was associated with a 1.28 [1.11-1.48] times higher odds for low PA in the overall sample. This association was driven by the particularly strong association observed in individuals aged ≥65years (odds ratio=1.65 [1.34-2.03]). Further adjustment for behavioral and health-related factors made very little difference to the estimates obtained in the model adjusted only for sociodemographic factors.

CONCLUSIONS

MCI was associated with an increased odds of not meeting the recommended PA levels. If replicated in longitudinal studies, these findings will offer new targets and strategies for prevention and treatment programs in people at risk for MCI and dementia.

Pre-ESRD Dementia and Post-ESRD Mortality in a Large Cohort of Incident Dialysis Patients

BACKGROUND

Conservative management may be a desirable option for elderly, fragile, or demented patients who reach end-stage renal disease (ESRD), yet some patients with dementia are placed on renal replacement therapy nonetheless.

METHODS

From a nationwide cohort of 45,076 US veterans who transitioned to ESRD over 4 contemporary years (October 1, 2007 to September 30, 2011), we identified 1,336 (3.0%) patients with International Classification of Diseases, Ninth Revision, Clinical Modification code-based dementia diagnosis during the prelude (predialysis) period. We examined the association of prelude dementia with all-cause mortality within the first 6 months following transition to dialysis, using a propensity-matched cohort and Cox proportional hazards models.

RESULTS

In the entire cohort, the overall mean ± standard deviation age at baseline was 72 ± 11 years, 95% were male, 23% were African-American, and 66% were diabetic. There were 8,080 (18.5%) deaths (mortality rate, 412; 95% confidence interval [CI], 403-421/1,000 patient-years) in the dementia-negative group, and 396 (29.6%) deaths (mortality rate, 708; 95% CI, 642-782/1,000 patient-years) in the dementia-positive group in the entire cohort in the first 6 months after dialysis initiation. Presence of dementia was associated with higher risk of all-cause mortality (adjusted hazard ratio, 1.25; 95% CI, 1.12-1.38) compared to dementia-free patients in the first 6 months after dialysis initiation.

CONCLUSION

Pre-ESRD dementia is associated with increased risk of early post-ESRD mortality in veterans transitioning to dialysis.