Compression or expansion of dementia in Germany? An observational study of short-term trends in incidence and death rates of dementia between 2006/07 and 2009/10 based on German health insurance data

The Impact of Sex-Specific Survival on the Incidence of Dementia in Parkinson's Disease

OBJECTIVE

The aim of our study is to analyze sex-specific patterns of Parkinson's disease dementia (PDD) incidence. We are investigating the extent to which sex differences in survival after initial Parkinson's disease (PD) diagnosis influence differences in PDD risk among PD patients.

METHODS

We used a random sample of German longitudinal health claims data of persons ages 50+ (2004-2019; n = 250,000) and identified new PD cases ages 65+ who were followed-up for a PDD diagnosis or death between 2006 and 2017. We performed Cox and competing-risk regression models, with death as competing event, to calculate PDD hazard ratios (HR) adjusted for age at PD onset, PD severity as measured by the modified Hoehn and Yahr (HY) scale, comorbidities, and medications.

RESULTS

Of 2195 new PD cases, 602 people died before PDD and 750 people developed PDD by the end of 2017. The adjusted risk of PDD differs by sex, with men having a higher PDD risk than women. When accounting for death, men and women do not differ in their PDD risk (HR = 1.02, P = 0.770). Sex-specific analyses showed significant age and severity effects in women (age: HR = 1.05, P < 0.001; HY 3-5 vs. 0-2.5: HR = 1.46, P = 0.011), but not in men.

CONCLUSION

Older age at first PD diagnosis and higher disease severity increase PDD risk, but this association is attenuated for PD men when controlling for death. This implies that the most frail PD men die rapidly before receiving a dementia diagnosis, whereas women with PD survive at higher rates, regardless of their age at onset and disease severity. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Incidence of dementia over a period of 20 years in a Norwegian population

INTRODUCTION

In Norway, the prevalence of dementia is higher than in demographically comparable, high income countries, but reliable incidence studies are lacking. This study calculated the incidence of age-specific dementia from 2000 to 2019.

METHODS

Participants from The Tromsø Study (n = 44,214) were included. Participants with a dementia diagnosis (n = 2049 cases) were identified. Poisson regression was used to calculate age-specific yearly and 5-year incidence rates from 2000 to 2019.

RESULTS

The incidence of dementia has decreased from 2000 to 2019. The trend was highly significant for ages of 60-99 years, and was similar for both sexes.

DISCUSSION

The incidence of dementia in North Norway has decreased over the past two decades similar to that in Western countries, indicating that the total prevalence is increasing due to an aging population. This decrease of incidence could introduce a reduction in future estimation of dementia prevalence.

Dementia in Germany: epidemiology, trends and challenges

Background

Dementia poses a growing challenge for individuals, healthcare, social support, and society amidst the ongoing ageing of populations. To evaluate the care requirements and social implications of dementia in Germany, reliable statistics regarding its current and future occurrence are necessary.

Methods

Using existing data sources and recent research results, this paper compiles and analyses relevant statistics on the occurrence of dementia in Germany, presents protective and risk factors, and options for care provision.

Results

Recent projections indicate a potential surge in the number of dementia patients in Germany, predicted to rise from 1.7 million at present to up to 3.0 million by the year 2070. Cognitive and motor deterioration and behavioural changes associated with dementia lower the ability to live independently. These changes are often tied to social exclusion and stigma and, particularly in the severe phase of the disease, necessitate extensive medical and care requirements. This contributes to dementia being one of the most costly diseases at old age from an overall societal perspective. Currently, there are no curative treatment options available.

Conclusions

To reduce the increase in the number of dementia patients and associated costs in the future, preventive approaches, particularly promoting a healthy lifestyle, may prove effective. Simultaneously, the healthcare system, society, and caregivers must prepare for the increasing number of dementia patients. Improved diagnostics, new forms of therapy, and social innovations that support those who are affected and their relatives can help reduce the burden of dementia and its associated costs.

New cases of dementia are rising in elderly populations in Wales, UK

Dementia is one of the most common diseases in elderly populations, and older populations are one of the fastest growing groups globally. Consequently, the number of people developing and living with dementia is likely to grow. Using longitudinal medical records from Wales, UK between 1999 and 2018, diagnoses of overall dementia and common subtypes were combined with demographic data to assess numbers of new and existing cases per year. Data extraction resulted in 161,186 diagnoses from 116,645 individuals. Mean age at diagnosis of dementia increased over this period, resulting in fewer younger people with the disease. New cases of dementia have risen, as has the number of people living with dementia. Individuals with dementia are also living longer, even accounting for their older age. This may present a challenge for healthcare systems as the number of elderly people living with dementia is expected to continue to grow.

Changes in disability over time among older working-age adults: Which global and specific limitations are increasing in Germany using the SHARE-data from 2004 to 2015?

Objectives

Previous studies have observed increasing limitations among the middle-aged, including those aged 40-64, raising the question how healthy work participation has changed. Helping answer this question, we ask: How have general and specific limitations changed in working and non-working adults in Germany?

Methods

We used population-based data of older working-age adults, aged 50-64 years old, from Germany provided by the Survey of Health Aging and Retirement (SHARE) study from 2004 to 2014 (N = 3522). Multiple logistic regression analyses were used to study changes in limitations over time.

Results

We found that employment rates generally increased over time, whereas limitation rates mostly increased among participants aged 50-54 and mostly decreased among participants aged 60-64 in both the working and non-working population. Regarding type of disability, increases were more pronounced with movement-related and general activity-related limitations.

Conclusion

Therefore, if the comparatively younger more-limited cohorts age and replace the older less-limited cohorts, a larger part of the working and non-working life might be expected to be spent with limitations in the future, and it seems questionable whether further substantial increases in healthy work participation can be achieved. Further prevention efforts and assistance should be directed at current middle-aged cohorts to improve and maintain their health, including adapting current working conditions to a work force with more limitations.

Compression and Expansion of Morbidity

BACKGROUND

Morbidity is said to be compressed when the interval from the onset of a disease or disability to death becomes shorter over time, or when the incidence of the disease or disability declines over time. In the reverse situation, morbidity is said to be expanded.

METHODS

This review is based on national and international studies retrieved by a selective literature search on secular trends in morbidity and mortality. The findings were derived from data from surveys and registries, and from the routine data of health insurance carriers.

RESULTS

Three different types of secular trends in morbidity were seen. For some diseases (e.g., lung cancer, stroke, and dementia), morbidity among the elderly was compressed over time. On the other hand, for multimorbidity and type 2 diabetes including comorbidities, morbidity expanded over time. Unexpectedly, a double development was seen in certain other conditions, with both compression among the elderly and expansion among the middle-aged: this was particularly so for myo - cardial infarction, grip strength, and indicators of general health.

CONCLUSION

The notion of morbidity being reduced by compression seems less tenable in view of the double development just mentioned. The findings suggest that the observed secular trend toward better health among the elderly has not persisted among the more recently born cohorts. This can have negative effects on social security systems, particularly with respect to retirement ages being deferred or made more flexible, as well as the cost of health care.

Sex and Gender Differences in Environmental Influences on Dementia Incidence in Germany, 2014-2019: An Observational Cohort Study Based on Health Claims Data

BACKGROUND

There is an ongoing debate about whether environmental characteristics influence dementia risk like individual traits do, and whether these differ by sex and gender.

OBJECTIVE

This study examines the influence of regional characteristics on the incidence of dementia and explores sex and gender differences using individual-level health information and regional characteristics.

METHODS

Using a random sample of 250,000 people aged 70 + insured through Germany's largest German public health agency, we analyzed quarterly data about diagnoses and place of residence from 2014 to 2019. Using five-digit postal codes, we added data on various dimensions of regional characteristics offered by the INKAR database and the 2011 Census database. We used multilevel survival regressions to tease out regional incidence differences while accounting for spatial clustering.

RESULTS

After adjusting for multi-morbidity and relocation-related selection bias, we saw that people living in regions with the highest tertile of income (HR = 0.87, p < 0.001), and who had the highest tertile of remaining life expectancy at age 60 (HR = 0.93, p = 0.012) had lower dementia risks. There was no gender difference in the regional income effect, but the effect of education (HR = 0.91, p = 0.015) was significant only for men and remaining life-expectancy was significant only for women (HR = 0.93, p = 0.026).

CONCLUSION

Environmental characteristics related to wealth and health resources of a region influence the risk of dementia among the elderly in Germany. This effect is independent of the health profiles of the individuals and differs between the two genders. Health policies need to acknowledge these modifiable risk factors and consider how they affect men and women differently.

A Decade of Decline in Serious Cognitive Problems Among Older Americans: A Population-Based Study of 5.4 Million Respondents

BACKGROUND

Numerous studies suggest the prevalence of dementia has decreased over the past several decades in Western countries. Less is known about whether these trends differ by gender or age cohort, and if generational differences in educational attainment explain these trajectories.

OBJECTIVE

1) To detect temporal trends in the age-sex-race adjusted prevalence of serious cognitive problems among Americans aged 65+; 2) To establish if these temporal trends differ by gender and age cohort; 3) To examine if these temporal trends are attenuated by generational differences in educational attainment.

METHODS

Secondary analysis of 10 years of annual nationally representative data from the American Community Survey with 5.4 million community-dwelling and institutionalized older adults aged 65+. The question on serious cognitive problems was, "Because of a physical, mental, or emotional condition, does this person have serious difficulty concentrating, remembering, or making decisions?"

RESULTS

The prevalence of serious cognitive problems in the US population aged 65 and older declined from 12.2% to 10.0% between 2008 and 2017. Had the prevalence remained at the 2008 levels, there would have been an additional 1.13 million older Americans with serious cognitive problems in 2017. The decline in memory problems across the decade was higher for women (23%) than for men (13%). Adjusting for education substantially attenuated the decline.

CONCLUSION

Between 2008 and 2017, the prevalence of serious cognitive impairment among older Americans declined significantly, although these declines were partially attributable to generational differences in educational attainment.

Mortality in Dementia from 1996 to 2015: A National Registry-Based Cohort Study

BACKGROUND

It remains unclear whether the increased focus on improving healthcare and providing appropriate care for people with dementia has affected mortality.

OBJECTIVE

To assess survival and to conduct a time trend analysis of annual mortality rate ratios (MRR) of dementia based on healthcare data from an entire national population.

METHODS

We assessed survival and annual MRR in all residents of Denmark ≥65 years from 1996-2015 using longitudinal registry data on dementia status and demographics. For comparison, mortality and survival were calculated for acute ischemic heart disease (IHD) and cancer.

RESULTS

The population comprised 1,999,366 people (17,541,315 person years). There were 165,716 people (529,629 person years) registered with dementia, 131,321 of whom died. From 1996-2015, the age-adjusted MRR for dementia declined (women: 2.76 to 2.05; men: 3.10 to 1.99) at a similar rate to elderly people without dementia. The sex-, age-, and calendar-year-adjusted MRR was 2.91 (95%CI: 2.90-2.93) for people with dementia. MRR declined significantly more for acute IHD and cancer. In people with dementia, the five-year survival for most age-groups was at a similar level or lower as that for acute IHD and cancer.

CONCLUSION

Although mortality rates declined over the 20-year period, MRR stayed higher for people with dementia, while the MRR gap, compared with elderly people without dementia, remained unchanged. For the comparison, during the same period, the MRR gap narrowed between people with and without acute IHD and cancer. Consequently, initiatives for improving health and decreasing mortality in dementia are still highly relevant.

N-Nitrosodimethylamine-Contaminated Valsartan and the Risk of Cancer

BACKGROUND

N-Nitrosodimethylamine (NDMA), classified as a probable human carcinogen, has been found as a contaminant in the antihypertensive drug valsartan. Potentially carcinogenic effects associated with the consumption of NDMAcontaminated valsartan have not yet been analyzed in large-scale cohort studies. We therefore carried out the study reported here to explore the association between NDMA-contaminated valsartan and the risk of cancer.

METHODS

This cohort study was based on longitudinal routine data obtained from a large German statutory health insurance provider serving approximately 25 million insurees. The cohort comprised patients who had filled a prescription for valsartan in the period 2012-2017. The endpoint was an incident diagnosis of cancer. Hazard ratios (HR) for cancer in general and for certain specific types of cancer were calculated by means of Cox regression models with time-dependent variables and adjustment for potential confounders.

RESULTS

A total of 780 871 persons who had filled a prescription for valsartan between 2012 and 2017 were included in the study. There was no association between exposure to NDMA-contaminated valsartan and the overall risk of cancer. A statistically significant association was found, however, between exposure to NDMA-contaminated valsartan and hepatic cancer (adjusted HR 1.16; 95% confidence interval [1.03; 1.31]).

CONCLUSION

These findings suggest that the consumption of NDMA-contaminated valsartan is associated with a slightly increased risk of hepatic cancer; no association was found with the risk of cancer overall. Close observation of the potential long-term effects of NDMA-contaminated valsartan seems advisable.

Effect of Square Dance Exercise on Older Women With Mild Mental Disorders

Many epidemiological studies have demonstrated the therapeutic benefits of exercise (EX) that can be used for adjunctive treatment in mental disorders. Despite several clinical experiments using exercise interventions, controlled studies are sparse in most disorder groups. Square dance is a popular aerobic exercise for older women in China. This study aimed to explore the effect of Chinese square dance exercise on mild mental disorders in older women. Participants included 109 older women with mild cognitive impairment from four large nursing homes. Participants were assigned either to the intervention group (n = 62) or the control group (n = 47), according to their residential nursing home. The intervention group underwent an 18-week square dance exercise, while the control group maintained their usual lifestyle. The outcomes were tested at baseline and weeks 9 and 18. The results showed that square dance exercise positively affected the results of all evaluations, especially on the participants' depressive symptoms and quality-of-life-related mental health. This study demonstrates that square dance exercise is a safe and effective approach for older women with mild cognitive impairment that benefits their long-term health.

The Effect of Chinese Square Dance Exercise on Cognitive Function in Older Women With Mild Cognitive Impairment: The Mediating Effect of Mood Status and Quality of Life

The present study aimed to assess the effects of square dance exercise on the cognitive function and quality of life in older women with mild cognitive impairment and to investigate the mediating role of a depressed mood and reduced quality of life in the relationship between square dance exercise and cognition. The study design was a single-blind whole-group controlled trial. A total of 136 eligible participants were divided according to their nursing home into either an experimental or control group. The nursing home grouping was determined by the drawing of lots. The Montreal Cognitive Assessment (MoCA), Quality of Life (SF-12) and Geriatric Depression Scale (GDS-15) were used to assess participants at baseline, week 9, and week 18, respectively. Generalized estimating equations (GEE) were used to compare the results at baseline with mid-test and post-test changes in cognitive function and quality of life. Maximum likelihood estimation (ML) and robust standard errors were used to perform the mediation model. The study results indicated that the experimental group (compared to the control group) had a significant improvement in cognitive function, quality of life, and mood state at baseline in the mid-test and post-test results. The results of this 18-week experiment showed that the exercise-cognition relationship was significantly mediated by a reduction in depressive symptoms (indirect effect: β = -0.375; 95% CI = -0.864 to -0.069) and an improvement in quality of life (indirect effect: β = -0.678; 95% CI = -1.222 to -0.290). This study revealed the effects of moderate-intensity square dance exercise on cognitive function and quality of life in older Chinese women with mild cognitive impairment and explored the potential mediating mechanisms. These findings can be used to inform the development of public health policies to promote brain health in older adults with mild cognitive impairment.

Incidence and risk factors of dementia and the primary subtypes in northern rural China

This study was carried out to estimate the incidence and to determine socio-demographic risk factors for dementia among individuals residing in rural northern China.The current prospective, population-based study was conducted between 2011 and 2016. Follow-up interviews were conducted annually from 2014 to 2016. The study involved 1511 dementia-free individuals aged 60 years or above from rural China. Standard criteria were used to make diagnoses for dementia and Alzheimer disease (AD).At least one follow up survey was completed with 1181 study participants. At the 5-year follow-up, 127 individuals had developed dementia, 75 had developed AD, and 32 had developed vascular dementia (VaD). With a total of 5649.2 risk years for the sample, the estimated incidence rates per 1000 person-years were 22.48 (95% CI: 18.62, 26.35) for dementia and 13.28 (95% CI: 10.29, 16.26) for AD. Incidence rates for dementia and AD increased with age across the 10-year age groups. Poor education (illiteracy) was an independent risk factor for both AD and VaD. Being engaged in social activities was an independent protective factor for VaD.The incidence of dementia in rural China was found to be higher than previously reported. Incidence of dementia increased with age, and AD was the most frequent type of dementia. Poor education was associated with a higher risk of VaD and AD. Engagement in social activities was an independent protective factor for VaD.

Assessing the Progression of Alzheimer's Disease in Real-World Settings in Three European Countries

BACKGROUND

There exists considerable variation in disease progression rates among patients with Alzheimer's disease (AD).

OBJECTIVE

The primary objective of this observational study is to assess the progression of AD by characterizing cognitive, functional, and behavioral changes during the follow-up period between 6 and 24 months.

METHODS

A longitudinal prospective study with community-dwelling patients with an established clinical diagnosis of AD of mild to moderate severity was conducted in Germany, Spain and the UK. A sample of 616 patients from 69 sites was included.

RESULTS

Patients had a mean of 1.9 years (SD = 1.9) since AD diagnosis at study inclusion. Cognitive symptoms were reported to have first occurred a mean of 1.1 years (SD = 1.7) prior to AD diagnosis and 1.4 (SD = 1.8) years prior to AD treatment. Patients initially diagnosed with mild and moderate AD spent a median (95%CI) of 3.7 (2.8; 4.4) and 11.1 (6.1, 'not reached') years until progression to moderate and severe AD, respectively, according to the Mini-Mental State Examination (MMSE) scores. A mixed model developed for cognitive, functional, and neuropsychiatric scores, obtained from study patients at baseline and during follow-up period, showed progressive deterioration of AD patients over time.

CONCLUSION

The study showed a deterioration of cognitive, functional, and neuropsychiatric functions during the follow-up period. Cognitive deterioration was slightly faster in patients with moderate AD compared to mild AD. The duration of moderate AD can be overestimated due to the use of retrospective data, lack of availability of MMSE scores in clinical charts and exclusion of patients at time of institutionalization.

Trend in the Incidence and Prevalence of Dementia in the Faroe Islands

Background:

Dementia has become an important public health, economic, and social issue. Knowledge about prevalence, incidence, and trends of dementia in a country is of crucial importance. However, no studies of incidence or prevalence of dementia have been undertaken in the Faroe Islands.

Objectives:

The aim was to estimate the overall and trend in incidence and prevalence of dementia among individuals ≥60 years in the Faroe Islands from 2010-2017.

Methods:

Population-based register study where all individuals ≥60 years with a dementia diagnosis from January 2010 to December 2017 were identified. The overall crude and age-and-sex-specific incidence and prevalence was assessed.

Results:

The overall crude incidence among individuals ≥60 years from 2010 to 2017 was 5.1 per 1000 individuals and the prevalence 22.5 per 1000 individuals. The age-and sex-standardized annual incidence of dementia fluctuated between 4.8 and 6.7 per 1000, with no clear secular trend while the age-and sex-standardized prevalence increased steadily from 14.5 in 2010 to 30.8 per 1000 individuals in 2017.

Conclusion:

The age-standardized incidence or prevalence estimates in the Faroes seem to be lower than in other countries. The incidence was relatively stable in the period while the prevalence of dementia simultaneously increased.

Generating national projections of dementia cases for Ireland using a calibrated macro-simulation model

INTRODUCTION

Epidemiological data on dementia is not available in many European countries and regions due to the high cost and complexity of conducting large scale dementia screening studies. The available epidemiological studies identify potentially substantial variation in the prevalence of dementia over time and across Europe.

METHODS

In this paper we generate simulations of the number of dementia cases in Ireland from 1991 to 2036 using a three-state Markov illness-death model. Parameters values are selected for each simulation from a range using a random parameter search pattern. We employ a novel calibration method which exploits the strong relationship between dementia, ageing and mortality. Simulation weights are generated based on differences between observed and modelled cohorts of older people and the reported number of deaths from dementia. Irish Census data from 1991 to 2016 and the number of recorded deaths due to dementia in 2018 are used as calibration points. A weighted average projection of the number of dementia cases is generated.

RESULTS

We estimate a weighted average number of cases of dementia in 2016 of 54 877 increasing to 98 946 in 2036; this estimate is substantially lower than the estimates generated using extrapolation methods. We show the wide range of possible outcomes given the range in the available parameter estimates and show that irrespective of whether the incidence rate of dementia is declining the number of cases of dementia is rapidly increasing due to population ageing.

CONCLUSION

Previous studies have used parameter estimates from meta-analyses of the literature or from individual studies. In this paper we supplement these with a calibration approach using observed cause of death and population age structure data. These additional sources of data can be used to generate estimates of dementia prevalence in any country or region which has census data and data on deaths due to dementia.

Correlates of Sleep Disturbance among Older Adults with Mild Cognitive Impairment: A Cross-Sectional Study

Individuals with mild cognitive impairment (MCI) are at high risk for dementia development. Sleep disturbance is often overlooked in MCI, although it is an important risk factor of cognitive decline. In the absence of a cure for dementia, managing the risk factors of cognitive decline in MCI is likely to delay disease progression. To develop interventions for sleep disturbance in MCI, its related factors should be explored. This study aimed to identify and compare the correlates of sleep disturbance in older adults with MCI and those in cognitively healthy older adults. A comparative cross-sectional study was adopted. Data were obtained from 219 Chinese community-dwelling older adults (female: 70.3%), which consisted of 127 older adults with MCI and 92 age-matched cognitively healthy controls. The candidate correlates of sleep disturbance included socio-demographic correlates, health-related factors, lifestyle-related factors and psychological factor. Descriptive, correlational and regression statistics were used for data analysis. The prevalence of sleep disturbance in MCI was 70.1% compared to that of 56.5% in cognitively healthy controls (p < 0.001). The multivariate analysis indicated that, in participants with MCI, depressive symptoms (Beta = 0.297, p = 0.001), comorbidity burden (Beta = 0.215, p = 0.012) and physical activity (Beta = −0.297, p = 0.001) were associated with sleep disturbance. However, in the cognitively healthy controls, only depressive symptoms (Beta = 0.264, p = 0.028) and comorbidity burden (Beta = 0.361, p = 0.002) were associated with sleep disturbance. This finding highlights that sleep disturbance is sufficiently prominent to warrant evaluation and management in older adults with MCI. Furthermore, the findings elucidate several important areas to target in interventions aimed at promoting sleep in individuals with MCI.

Correlates of Health-Related Quality of Life Among Chinese Older Adults with Mild Cognitive Impairment

Purpose

This study aimed to assess the health-related quality of life (HRQoL) and identify the important correlates of HRQoL in older Chinese adults with mild cognitive impairment (MCI).

Patients and methods

A cross-sectional study design was adopted. A total of 204 older adults with MCI were enrolled in this study. HRQoL was evaluated by the Quality of Life-Alzheimer's disease. Hierarchical regression analysis was conducted to investigate the sociodemographic, disease-related, psychological, and behavioral factors associated with the HRQoL of individuals with MCI.

Results

Hierarchical regression analysis indicated that old age (Beta = -0.131, p =0.024), low income (Beta = 0.128, p = 0.032), depressive symptoms (Beta = -0.564, p < 0.001), and poor sleep quality (Beta = -0.169, p =0.004) were significantly associated with the HRQoL of individuals with MCI.

Conclusion

Caring for older Chinese adults with MCI should focus on sociodemographically disadvantaged groups with advanced age and low income. Rehabilitation programs that effectively alleviate depressive symptoms and improve sleep quality should be applied to older adults with MCI to enhance their HRQoL.

Role of depressive symptoms in subjective memory complaint in older adults with mild cognitive impairment

AIMS

To explore the independent relationship between depressive symptoms and subjective memory complaint (SMC) amongst older adults with mild cognitive impairment (MCI) after adjusting for objective cognitive function and other important confounding factors.

BACKGROUND

subjective memory complaint is a core symptom of MCI and is often the primary reason for older adults with MCI to seek for medical help. Improving subjective memory amongst older adults with MCI is important to enhance their quality of life and potentially delay further cognitive decline. Depressive symptoms, which are highly prevalent neuropsychiatric symptoms amongst older adults with MCI, may be one of the reasons that affect an individual's self-perception of memory function. However, there is a dearth of studies to provide a thorough evaluation of the independent relationship between depressive symptoms and SMC amongst older adults with MCI.

DESIGN

A descriptive correlational study.

METHODS

A consecutive sample (N = 154) of adults aged over 60 years was recruited from a community healthcare centre between June and September 2016. MCI was detected using the Montreal Cognitive Assessment. Depressive symptoms and subjective memory were measured using the Geriatric Depression Scale and Memory Inventory for the Chinese, respectively. Hierarchical regression was performed to explore the relationship between SMC and depressive symptoms, with control over objective cognitive function, socio-demographic and health-related confounding factors.

RESULTS

After controlling objective cognitive function and other confounding factors, SMC was independently associated with depressive symptoms (standardised β = 0.336, p < .001). This psychological status even explained for a greater variance (R²  = 8.8%) for SMC compared with objective cognitive function (R²  = 2.4%).

CONCLUSION

subjective memory complaint was independently associated with depressive symptoms in older adults with MCI. Early detection and management of depressive symptoms are highly important amongst this clinical cohort.

IMPLICATIONS FOR PRACTICE

Early detection and prompt treatment of depressive symptoms is a highly prioritised care agenda in managing SMC in older adults with MCI.

Gender and Age Differences and the Trend in the Incidence and Prevalence of Dementia and Alzheimer's Disease in Taiwan: A 7-Year National Population-Based Study

Background

Very few nationwide studies have focused on the variations in the incidence and prevalence of dementia and Alzheimer's disease (AD) in Asian countries. This study aims to describe the gender and age differences in the incidence and prevalence of dementia and AD in Taiwan.

Methods

The data on dementia and AD were acquired from the Taiwan National Health Insurance Research Database from 2004 to 2010. The sex and age-specific rates were standardized, and the differences of gender and age on dementia or AD were assessed using Poisson regression analysis.

Results

Over seven years, the prevalence of dementia and AD significantly increased from 4.7 to 7.6 per hundred people (β = 0.0784, p < 0.0001) and 2.3 to 3.5 per hundred people (β = 0.0696, p < 0.0001), respectively. However, the incidence of both dementia and AD decreased but not significantly from 10.9 to 10.7 and 4.9 to 4.6 per thousand person-years, respectively. Noticeably, both incidence and prevalence increased with age and were higher in women than in men.

Conclusions

The standardized incidence rates of dementia and AD are much lower than the data reported in some studies from Europe, the US, and Japan. Further studies are warranted to explore which factors are associated with the differences in the incidence of dementia and AD in Taiwan.

A multi-state model based reanalysis of the Framingham Heart Study: Is dementia incidence really declining?

Recent research by Satizabal and colleagues using data from the Framingham Heart Study demonstrated a linear decline in dementia incidence since the 1970s. The aim of this study is to re-examine these findings, given concerns that bias resulted from failure to account for the probability of acquiring dementia between the last dementia-free observation and death. This analysis included 5118 persons 60+ years of age, and determined the 5-year dementia incidence during four non-overlapping epochs. In addition to a replication using Cox proportional hazards, we applied separate Cox models (given unequal hazards across epochs) and a Spline-based penalized likelihood approach based on the illness-death multi-state model. In addition, we present a simulation study demonstrating the bias associated with the use of standard survival models. The simulation showed that estimates of disease incidence derived from the multi-state model-based approach were consistent with the true disease incidence, whereas Cox regression 'censoring' observations at death or at last observation consistently underestimated it. Using the Framingham data, the 5-year age- and sex-adjusted cumulative hazard rates for dementia as derived from the multi-state model-based approach were 3.84, 2.66, 3.29 and 3.13 per 100 persons in epochs 1, 2, 3 and 4 respectively. The findings do not support the conclusion that dementia incidence has declined in the Framingham Heart Study over the given time period. Previous findings of a decline may have been an artefact resulting from improper treatment of those cases in which death precluded the observation of dementia onset.

Secular Trends in Dementia Prevalence and Incidence Worldwide: A Systematic Review

BACKGROUND

Time trends for dementia prevalence and incidence rates have been reported over the past seven decades in different countries and some have reported a decline.

OBJECTIVE

To undertake a systematic review to critically appraise and provide an evidence-based summary of the magnitude and direction of the global changes in dementia prevalence and incidence across time.

METHODS

Medline, EMBASE, and PsychINFO were searched for studies focused on secular trends in dementia prevalence and/or incidence until 18 December 2017. In total, 10,992 articles were identified and 43 retained.

RESULTS

Overall, prevalence rates are largely increasing (evidence primarily from record-based surveys and cohort studies in Japan, Canada, and France) or have remained stable (evidence primarily from cohort studies in Sweden, Spain and China). A significant decline in prevalence has however been reported in more recent studies (i.e., from 2010 onwards) from Europe (e.g., UK and Sweden) and the USA. Incidence rates have generally remained stable or decreased in China, Canada, France, Germany, Denmark, Sweden, the Netherlands, UK, and USA. An increase has only been reported in five countries: Italy, Japan, Wales, Germany, and the Netherlands. Only one study reported findings (stability in incidence) from a low and middle-income country using data from Nigeria.

CONCLUSIONS

The evidence on secular trends in the prevalence and incidence of dementia is mixed including contradictory findings using different (and in some cases the same) datasets in some countries (e.g., the USA, UK, and Sweden). This making it difficult to draw concrete conclusions. However, declining trends recently observed in some high-income Western countries in the most recent two decades including the UK, USA, and Sweden are encouraging. Updated dementia prevalence and incidence estimates will inform public health and financial planning as well as development of prevention strategies.

Identifying the Factors Related to Depressive Symptoms Amongst Community-Dwelling Older Adults with Mild Cognitive Impairment

High-level depressive symptoms have been reported in individuals with mild cognitive impairment (MCI), resulting in increased risk of progression to dementia. However, studies investigating the correlates of depressive symptoms among this population are scarce. This study aimed to investigate the significant socio-demographic, lifestyle-related and disease-related correlates of depressive symptoms among this cohort. Cross-sectional data were obtained from a sample of 154 Chinese community-dwelling older adults with MCI. MCI subjects were screened by the Montreal Cognitive Assessment. Depressive symptoms were measured by the Geriatric Depression Scale. Possible correlates of depressive symptoms in individuals with MCI were explored by multiple linear regressions. The prevalence of depressive symptoms among Chinese older adults with MCI was 31.8%. In multiple regression analysis, poor perceived positive social interaction, small social network, low level of physical activity, poor functional status, subjective memory complaint, and poor health perception were correlated with depressive symptoms. The findings highlight that depressive symptoms are sufficient to warrant evaluation and management in older adults with MCI. Addressing social isolation, assisting this vulnerable group in functional and physical activities, and cultivating a positive perception towards cognitive and physical health are highly prioritized treatment targets among individuals with MCI.

[The future development of dementia diseases in Germany-a comparison of different forecast models]

Dementia is one of the most frequent diseases of people aged 65 and older. As a result of the upcoming demographic transition, a significant increase is expected to the current number of around 1.7 million dementia patients. A precise estimate of this increase is especially important for decision-makers and payers to the health-care system. This study examined the effects of different assumptions on the future frequency of disease using a time-discrete Markov model with population-related and disease-specific components. Based on health insurers' administrative data from AOK Baden-Württemberg, we determined age- and gender-specific prevalence rates, incidence rates, and mortality differences of dementia patients and combined them with demographic components from German population statistics. As a result, our Markov model showed a 20 to 25% higher number of dementia patients in 2030, compared to the results of the status quo projection applied in most previous studies, with the assumption of constant prevalence rates over time. Hence, our results indicate that even in the medium term payers will have to face significant increases in dementia-related health expenditures. By 2060, the number of dementia patients in Germany would rise to 3.3 million assuming a further increase to life expectancy and constant incidence rates over time. The assumption of a compression of the morbidity would reduce this number to 2.6 million.

Aging without Dementia is Achievable: Current Evidence from Epidemiological Research

Both the incidence and the prevalence of dementia increase exponentially with increasing age. This raises the question of whether dementia is an inevitable consequence of aging or whether aging without dementia is achievable. In this review article, we sought to summarize the current evidence from epidemiological and neuropathological studies that investigated this topic. Epidemiological studies have shown that dementia could be avoided even at extreme old ages (e.g., centenarians or supercentenarians). Furthermore, clinico-neuropathological studies found that nearly half of centenarians with dementia did not have sufficient brain pathology to explain their cognitive symptoms, while intermediate-to-high Alzheimer pathology was present in around one-third of very old people without dementia or cognitive impairment. This suggests that certain compensatory mechanisms (e.g., cognitive reserve or resilience) may play a role in helping people in extreme old ages escape dementia syndrome. Finally, evidence has been accumulating in recent years indicating that the incidence of dementia has declined in Europe and North America, which supports the view that the risk of dementia in late life is modifiable. Evidence has emerged that intervention strategies that promote general health, maintain vascular health, and increase cognitive reserve are likely to help preserve cognitive function till late life, thus achieving the goal of aging without dementia.

[Trends in the Prevalence of Dementia and Parkinson's Disease: An Analysis Based on Health Claims Data from all German Statutory Health Insurance Funds for Persons aged 65+in Germany 2009-2012]

OBJECTIVES

There will be an increase in the number of people with dementia (DEM) and Parkinson's disease (PD) with the ageing of the population. The aim of the study was to calculate prevalences and trends of prevalences for DEM and PD in Germany to enable reliable public health planning.

METHODS

For the years 2009-2012, sex-specific period prevalences of DEM and PD for 5-year age-groups based on health claims data from all German statutory health insurance funds were calculated. Time trends were estimated using a negative binomial regression.

RESULTS

In 2012 and for persons aged 65 or older, the crude prevalence was 7.9% for DEM and 2.2% for PD. Between 2009 and 2012, a mean decrease of the DEM prevalence by 1.2% per year was found for women and men above age 65. For PD we found constant rates between 2009-2012 among men and an annual mean decrease of PD prevalence of 0.5% among women.

CONCLUSION

A reduction of the DEM prevalence by 1.2% per year could partially counterbalance the increase of people with dementia resulting from ageing population. For PD we found decreasing prevalences only among women.

Effects of a moderate-intensity aerobic exercise programme on the cognitive function and quality of life of community-dwelling elderly people with mild cognitive impairment: A randomised controlled trial

BACKGROUND

Individuals with mild cognitive impairment have a heightened risk of developing dementia. Physical exercise, especially moderate-intensity aerobic exercise, is a promising lifestyle intervention to improve the cognitive function of this patient group. However, the mechanisms underlying the exercise-cognition relationship are not fully understood. Whether the cognitive benefits of physical exercise can improve the overall well-being of this group remains unknown. This study aims to address these research gaps in the under-researched Chinese population.

OBJECTIVES

This study aimed to evaluate the effects of a moderate-intensity aerobic exercise programme on the cognitive function and health-related quality of life of Chinese elderly with mild cognitive impairment and to explore the mediating roles of depressive mood and sleep quality in the exercise-cognition relationship.

DESIGN

A single-blinded randomised controlled trial.

SETTINGS AND PARTICIPANTS

This study was conducted in two urban community healthcare centres in Hangzhou City, China. Elderly people aged over 60 years screened with mild cognitive impairment were included.

METHODS

A total of 120 eligible participants were randomly assigned to receive either the group-based moderate-intensity aerobic exercise programme or the health education programme (as attention-placebo control). Montreal Cognitive Assessment, Quality of Life-Alzheimer's Disease, Geriatric Depression Scale and Pittsburgh Sleep Quality Index were administered at baseline before randomisation and immediately after the completion of the interventions. Analysis followed the intention-to-treat principle. Generalised estimating equation was used to compare the changes in the cognitive function and health-related quality of life over the pre-test and post-test periods between the groups. The mediating roles of depressive mood and sleep quality in the exercise-cognition relationship were examined with the PROCESS macro.

RESULTS

Participants in the intervention group had a significantly greater improvement in terms of cognitive function (β = 1.895; 95% confidential interval [CI] = 1.421, 2.368; p <  0.001) and health-related quality of life (β= 0.605; 95% CI= 0.295, 0.914; p <  0.001) compared with the control group over the pre-test and post-test periods. The exercise-cognition relationship was significantly mediated by reduced depressive symptoms (indirect effect: β= -0.705; 95% CI: -1.028, -0.382) and improved sleep quality (indirect effect: β=-0.205; 95% CI: -0.122, 0.831).

CONCLUSIONS

This study revealed the benefits and outlined the underlying mediating mechanism of an aerobic exercise programme to the cognitive function and health-related quality of life of Chinese elderly people with mild cognitive impairment. The findings provided insights into the development of public health initiatives to promote brain health amongst the elderly with mild cognitive impairment.

Secular trends of mortality and dementia-free life expectancy over a 10-year period in France

The aim of this paper was to investigate the evolution of mortality and life expectancy according to dementia in two French populations 10 years apart. Two different populations of subjects aged 65 or older included in PAQUID from 1988 to 1989 (n = 1342) and 3C from 1999 to 2000 (n = 1996) and initially not demented were followed over 10 years. Dementia was assessed using an algorithmic approach, and participants were considered to have dementia if they had an MMSE score < 24 AND a 4IADL score > 1. Illness-death models were used to compare mortality with and without dementia and to provide total life expectancy (LE), dementia-free life expectancy (DemFreeLE), life expectancy with dementia (DemLE), and survival with dementia. Mortality without dementia has decreased between the two populations among men [HR = 0.63 (0.49-0.81)] and women [HR = 0.67 (0.50-0.90)], whereas mortality with dementia has decreased for women only [HR = 0.59 (0.41-0.87)]. Total LE and DemFreeLE have increased between the 1990s and the 2000s populations (total LE: + 2.5 years; DemFreeLE: + 2.2 years); DemLE only slightly increased between the populations (DemLE: + 0.3 years). For survival with dementia, an increase in survival has been evidenced (mean survival: + 1.3 years) for women only. The improvement in DemFreeLE is promising. However, as the duration of life with dementia tends to increase for women, efforts to delay the onset of dementia should be reinforced.

Morbidity compression in myocardial infarction 2006 to 2015 in terms of changing rates and age at occurrence: A longitudinal study using claims data from Germany

BACKGROUND

According to James Fries morbidity compression is present if morbidity rates are decreasing to a larger extent than mortality rates. Compression also occurs if age at onset is increasing at a faster pace than age at death. These two variants of the compression hypothesis were formulated as a population concept. Compression has seldom been studied with a specific disease as application.

METHODS

Morbidity compression was examined in terms of myocardial infarction (MI) by using German claims data covering the years 2006 to 2015. The findings are based on an annual case number of about 2 m women and men aged 18 years and older. Analyses were performed by means of proportional hazards regression and by using linear regression.

RESULTS

Decreases of morbidity rates were more pronounced than those of mortality. For men, the hazard ratio for contracting MI in 2015 as compared to 2006 was hr = 0.66 and hr = 0.71 for the female population. The respective results for mortality were hr = 0.75 in men and hr = 1.0 in women. They can be interpreted in favor of morbidity compression. For the subgroup of women and men with MI, changes of onset age revealed marked gender differences. For 2015 as compared with 2006, age at MI-occurrence in men increased by 10.5 months as compared to an increase of 10.4 months for age at death. In women changes were smaller and statistically not significant. The findings referring to women have to be interpreted against the backdrop of higher onset age and higher age at death than in men.

CONCLUSIONS

Taken together, morbidity compression has occurred in terms of decreasing MI-rates as well as in terms of increased onset age in men. It can be concluded that both processes have led to an improvement of healthy lifetime. Decreasing morbidity rates in women are also pointing towards morbidity compression, a finding that is not complemented by changes of onset age. Our data are demonstrating that morbidity rates and age at onset may vary independently. From this perspective morbidity compression is a multi-faceted phenomenon.

Evolution of dementia diagnosis over time (1988-2013): Evidence from French and English cohorts. Implication for secular trends analyses

INTRODUCTION

The aims of this study are to examine the evolution of clinical dementia diagnosis over 3 decades and to investigate secular trends of dementia.

METHODS

Four cohorts covering a period from 1988 to 2013 were used: the Personnes Agées Quid and Three-City-Bordeaux studies, and the Cognitive Function and Aging Study (CFAS) I and II. Mini-Mental State Examination scores at clinical diagnosis were evaluated over a 24-year follow-up period in French studies. An algorithmic approach was applied to CFAS I and II to provide dementia prevalence and incidence estimates.

RESULTS

A significant increase of the Mini-Mental State Examination score at diagnosis was observed until 2000 and a significant decrease after. We reported a prevalence of 8.8% for CFAS I (1990-1993) compared with a prevalence of 6.5% in CFAS II (2008-2011). The 2-year incidence rate was estimated at 31.2/1000 (95% confidence interval = 28.0-34.8) for CFAS I and 15.0/1000 (95% confidence interval = 13.5-16.7) for CFAS II.

DISCUSSION

Applying a stable algorithm to different cohorts across time can provide a robust method for time trends estimation.

Regular Benzodiazepine and Z-Substance Use and Risk of Dementia: An Analysis of German Claims Data

BACKGROUND

While acute detrimental effects of benzodiazepine (BDZ), and BDZ and related z-substance (BDZR) use on cognition and memory are known, the association of BDZR use and risk of dementia in the elderly is controversially discussed. Previous studies on cohort or claims data mostly show an increased risk for dementia with the use of BDZs or BDZRs. For Germany, analyses on large population-based data sets are missing.

OBJECTIVE

To evaluate the association between regular BDZR use and incident any dementia in a large German claims data set.

METHODS

Using longitudinal German public health insurance data from 2004 to 2011 we analyzed the association between regular BDZR use (versus no BDZR use) and incident dementia in a case-control design. We examined patient samples aged≥60 years that were free of dementia at baseline. To address potential protopathic bias we introduced a lag time between BDZR prescription and dementia diagnosis. Odds ratios were calculated applying conditional logistic regression, adjusted for potential confounding factors such as comorbidities and polypharmacy.

RESULTS

The regular use of BDZRs was associated with a significant increased risk of incident dementia for patients aged≥60 years (adjusted odds ratio [OR] 1.21, 95% confidence interval [CI] 1.13-1.29). The association was slightly stronger for long-acting substances than for short-acting ones. A trend for increased risk for dementia with higher exposure was observed.

CONCLUSION

The restricted use of BDZRs may contribute to dementia prevention in the elderly.

Time, Sex, Gender, History, and Dementia

A growing body of epidemiologic evidence indicates a decline in the incidence or prevalence of dementia in high income countries in the past 25 years. In this commentary, I first suggest that the decline in the incidence or prevalence of dementia is not explained completely by the factors considered so far, and that a broader historical perspective may be needed. Second, I suggest that the overall declining trend may conceal trends in opposite directions for the two major subtypes of dementia, the neurovascular and the neurodegenerative type. Third, I suggest some areas of future research to further elucidate the trends. The future of dementia remains somewhat unclear. Even if the incidence continues to decline, the prevalence may remain the same or increase if survival of persons affected by dementia increases. In addition, even if the prevalence declines, the total number of persons affected by dementia may remain the same or increase if the size of the elderly population expands. Finally, we cannot be sure that the decline in incidence will continue in the coming decades. With cautious optimism, we may conclude that the burden of dementia may be modified over time by human practices, including public health and medicine.

Physical activity and cohabitation status moderate the link between diabetes mellitus and cognitive performance in a community-dwelling elderly population in Germany

AIMS/HYPOTHESIS

The increasing number of people with dementia and cognitive impairments makes it essential to detect and prevent modifiable risk factors of dementia. This study focuses on type 2 diabetes mellitus, especially on undiagnosed cases and their increased risk of cognitive impairment. Furthermore, the potential of physical activity and social integration to moderate the relation between diabetes and cognitive impairment is assessed.

METHODS

We used cross-sectional data from 1299 participants of the Berlin Aging Study II (BASE-II) aged between 60 to 84 years and performed logistic regression models to analyze the association of diabetes status, physical activity, and cohabitation status with poor cognitive performance. Cognitive performance was measured with the Consortium to Establish a Registry for Alzheimer's Disease (CERAD)-Plus test battery.

RESULTS

Undiagnosed diabetes (odds ratio (OR) = 2.12, p = 0.031), physical inactivity (OR = 1.43, p = 0.008) and non-cohabiting (OR = 1.58, p = 0.002) were associated with an increased likelihood of poor cognitive performance. The highest odds were observed in participants who suffered from undiagnosed or insulin-dependent diabetes and, in addition, were inactive (undiagnosed diabetes: OR = 3.44, p = 0.003; insulin-dependent diabetes: OR = 6.19, p = 0.019) or lived alone (undiagnosed diabetes: OR = 4.46, p = 0.006; insulin-dependent diabetes: OR = 6.46 p = 0.052). Physical activity and cohabiting appeared to be beneficial.

CONCLUSIONS/INTERPRETATION

Physical activity and cohabitation status moderate the link between diabetes mellitus and cognitive performance. Special attention should be paid to undiagnosed and insulin-dependent diabetes cases, which have a particularly high risk of poor cognitive performance.

Temporal trend in dementia incidence since 2002 and projections for prevalence in England and Wales to 2040: modelling study

Objective To forecast dementia prevalence with a dynamic modelling approach that integrates calendar trends in dementia incidence with those for mortality and cardiovascular disease.Design Modelling study.Setting General adult population of England and Wales.Participants The English Longitudinal Study of Ageing (ELSA) is a representative panel study with six waves of data across 2002-13. Men and women aged 50 or more years, selected randomly, and their cohabiting partners were recruited to the first wave of ELSA (2002-03). 11392 adults participated (response rate 67%). To maintain representativeness, refreshment participants were recruited to the study at subsequent waves. The total analytical sample constituted 17 906 people. Constant objective criteria based on cognitive and functional impairment were used to ascertain dementia cases at each wave.Main outcome measures To estimate calendar trends in dementia incidence, correcting for bias due to loss to follow-up of study participants, a joint model of longitudinal and time-to-event data was fitted to ELSA data. To forecast future dementia prevalence, the probabilistic Markov model IMPACT-BAM (IMPACT-Better Ageing Model) was developed. IMPACT-BAM models transitions of the population aged 35 or more years through states of cardiovascular disease, cognitive and functional impairment, and dementia, to death. It enables prediction of dementia prevalence while accounting for the growing pool of susceptible people as a result of increased life expectancy and the competing effects due to changes in mortality, and incidence of cardiovascular disease.Results In ELSA, dementia incidence was estimated at 14.3 per 1000 person years in men and 17.0/1000 person years in women aged 50 or more in 2010. Dementia incidence declined at a relative rate of 2.7% (95% confidence interval 2.4% to 2.9%) for each year during 2002-13. Using IMPACT-BAM, we estimated there were approximately 767 000 (95% uncertainty interval 735 000 to 797 000) people with dementia in England and Wales in 2016. Despite the decrease in incidence and age specific prevalence, the number of people with dementia is projected to increase to 872 000, 1 092 000, and 1 205 000 in 2020, 2030, and 2040, respectively. A sensitivity analysis without the incidence decline gave a much larger projected growth, of more than 1.9 million people with dementia in 2040.Conclusions Age specific dementia incidence is declining. The number of people with dementia in England and Wales is likely to increase by 57% from 2016 to 2040. This increase is mainly driven by improved life expectancy.

The changing prevalence and incidence of dementia over time - current evidence

Dementia is an increasing focus for policymakers, civil organizations and multidisciplinary researchers. The most recent descriptive epidemiological research into dementia is enabling investigation into how the prevalence and incidence are changing over time. To establish clear trends, such comparisons need to be founded on population-based studies that use similar diagnostic and research methods consistently over time. This narrative Review synthesizes the findings from 14 studies that investigated trends in dementia prevalence (nine studies) and incidence (five studies) from Sweden, Spain, the UK, the Netherlands, France, the USA, Japan and Nigeria. Besides the Japanese study, these studies indicate stable or declining prevalence and incidence of dementia, and some provide evidence of sex-specific changes. No single risk or protective factor has been identified that fully explains the observed trends, but major societal changes and improvements in living conditions, education and healthcare might have favourably influenced physical, mental and cognitive health throughout an individual's life course, and could be responsible for a reduced risk of dementia in later life. Analytical epidemiological approaches combined with translational neuroscientific research could provide a unique opportunity to explore the neuropathology that underlies changing occurrence of dementia in the general population.

Extremity injuries and dementia disproportionately increase the risk for long-term care at older age in an analysis of German Health Insurance routine data for the years 2006 to 2010

Background

Extremity injuries (EI) and dementia are important causes of long-term care (LTC), but they can also cause each other and are often present concurrently. Mobility-limiting EI can increase the risk of dementia, and dementia increases the risk for falls, which are often the cause of EI. When EI and dementia are present together, they can increase their negative effect on long-term care risk. This study aims to assess the strength of this interaction and the role of different body regions and severities of EI regarding LTC risk.

Methods

We use Cox proportional-hazard models on LTC as dependent variable. EI (primarily fractures) and dementia (all types) are the central independent variables. We control for age, sex, rehabilitation and 18 relevant comorbidities. Analyses are based on health claims records for 2004–2010 for a random sample of about 122.000 insurants of Germany's largest public health insurance "AOK" aged 65+, about 25.000 of whom entered LTC.

Results

Without concurrent dementia, non-severe EI (NSEI) of the lower and both extremities and all kinds of severe EI (SEI) increase LTC risk (HR: hazard ratio with 95% confidence interval. Lower NSEI: HR = 1.09 [1.05–1.14]; both NSEI: HR = 1.36 [1.29–1.44]. Lower SEI: HR = 1.67 [1.57–1.79]; upper SEI: HR = 1.27 [1.19–1.37]; both SEI: HR = 1.94 [1.81–2.07]). Dementia alone increases LTC risk more than fourfold (HR = 4.23 [4.11–4.35]).

Taking the interaction of EI and dementia into account, the concurrent presence of EI and dementia tends to increase the LTC risk more than expected for lower as well as upper NSEI and SEI. Summarily, when lower or upper EI and dementia are both present, the LTC risk tends to be higher than expected, suggesting synergistic effects.

Conclusions

EI and dementia are important independent risk factors for long-term care. When lower or upper EI and dementia are present together, the resulting long-term care risk is increased disproportionately. Since the concurrent presence of both conditions increases the risk for care need, and a working treatment for dementia is not in sight, preventing EI, lessening the impact of EI and improving the outlook after an EI could help to reduce LTC need in the coming decades.

Recent global trends in the prevalence and incidence of dementia, and survival with dementia

BACKGROUND

Current projections of the scale of the coming dementia epidemic assume that the age- and sex-specific prevalence of dementia will not vary over time, and that population ageing alone (increasing the number of older people at risk) drives the projected increases. The basis for this assumption is doubtful, and secular trends (that is, gradual decreases or increases in prevalence over long-term periods) are perfectly plausible.

METHODS

We carried out a systematic review of studies of trends in prevalence, incidence and mortality for people with dementia, conducted since 1980.

RESULTS

We identified nine studies that had tracked dementia prevalence, eight that had tracked dementia incidence, and four that had tracked mortality among people with dementia. There was some moderately consistent evidence to suggest that the incidence of dementia may be declining in high-income countries. Evidence on trends in the prevalence of dementia were inconsistent across studies and did not suggest any clear overall effect. Declining incidence may be balanced by longer survival with dementia, although mortality trends have been little studied. There is some evidence to suggest increasing prevalence in East Asia, consistent with worsening cardiovascular risk factor profiles, although secular changes in diagnostic criteria may also have contributed.

CONCLUSIONS

We found no evidence to suggest that the current assumption of constant age-specific prevalence of dementia over time is ill-founded. However, there remains some uncertainty as to the future scale of the dementia epidemic. Population ageing seems destined to play the greatest role, and prudent policymakers should plan future service provision based upon current prevalence projections. Additional priorities should include investing in brain health promotion and dementia prevention programs, and monitoring the future course of the epidemic to chart the effectiveness of these measures.