A commentary on studies presenting projections of the future prevalence of dementia

Prevalence of Dementia in Puerto Rican Veterans is Higher than in Mainland U.S. Veterans

Introduction Dementia is a common neurological condition affecting many older individuals that leads to a loss of independence, diminished quality of life, premature mortality, caregiver burden and high levels of healthcare utilization and cost. This is an updated systematic review and meta-analysis of the worldwide prevalence and incidence of dementia. The MEDLINE and EMBASE databases were searched for relevant studies published between 2000 (1985 for Canadian papers) and July of 2012. Papers selected for full-text review were included in the systematic review if they provided an original population-based estimate for the incidence and/or prevalence of dementia. The reference lists of included articles were also searched for additional studies. Two individuals independently performed abstract and full-text review, data extraction, and quality assessment of the papers. Random-effects models and/or meta-regression were used to generate pooled estimates by age, sex, setting (i.e., community, institution, both), diagnostic criteria utilized, location (i.e., continent) and year of data collection. Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 160 studies met the inclusion criteria. Among individuals 60 and over residing in the community, the pooled point and annual period prevalence estimates of dementia were 48.62 (CI95%: 41.98-56.32) and 69.07 (CI95%: 52.36-91.11) per 1000 persons, respectively. The respective pooled incidence rate (same age and setting) was 17.18 (CI95%: 13.90-21.23) per 1000 person-years, while the annual incidence proportion was 52.85 (CI95%: 33.08-84.42) per 1,000 persons. Increasing participant age was associated with a higher dementia prevalence and incidence. Annual period prevalence was higher in North America than in South America, Europe and Asia (in order of decreasing period prevalence) and higher in institutional compared to community and combined settings. Sex, diagnostic criteria (except for incidence proportion) and year of data collection were not associated with statistically significant different estimates of prevalence or incidence, though estimates were consistently higher for females than males. Dementia is a common neurological condition in older individuals. Significant gaps in knowledge about its epidemiology were identified, particularly with regard to the incidence of dementia in low- and middle-income countries. Accurate estimates of prevalence and incidence of dementia are needed to plan for the health and social services that will be required to deal with an aging population.

Background: There is an acknowledged lack of information about dementia in Ireland, including very poor coding of dementia across all care settings. Yet with dementia prevalence set to increase as our population ages, there is an urgent need to gather valid epidemiological data that provides accurate and reliable national estimates of current and future dementia prevalence, and facilitates the development of robust and effective dementia health and social policy (Cahill, O’Shea, & Pierce, 2012). This study, commissioned as part of the Alzheimer Society of Ireland evidence-based policy series, examined the feasibility of developing a national dementia register for Ireland. Methods: A rapid review of national and international patient registry literature was undertaken to identify registry functions, underlying design and process models, and best-practice guidelines for their development. A ‘landscape analysis’ identified the legal, ethical, clinical, technology, and financial issues relevant to the creation of an Irish dementia register. Following ethical approval, we conducted two focus groups with people with dementia and twenty-one expert stakeholder interviews with clinicians and with representatives from research, health, and social care organisations in Ireland and the UK, existing Irish patient registries, and international dementia registries. Discussions followed an agreed structure, were audio-recorded, transcribed, and analysed using inductive content analysis. Results: Common themes emerged from the literature and stakeholder discussions with regard to: registry function; benefits and risks; data collection; data management; governance; legislation; barriers and facilitators; Irish complexities; and best-practice. Conclusions: The results provide an evidence-base on which to progress the issue of improved recording structures for dementia in Ireland. Given the strategic approach the government is now taking to address research and information systems as part of the 2014 National Dementia Strategy, it is opportune to examine the potential for a framework to collect information in a reliable, accurate, valid, complete, and timely way

With dementia prevalence set to increase as our population ages, there is an urgent need to gather valid epidemiological data in Ireland that provides accurate and reliable estimates of current and future dementia prevalence and facilitates the development of effective dementia health and social policy. This study examined the feasibility of developing a national dementia register for Ireland. A rapid review of national and international patient registry literature was undertaken to identify registry functions, underlying design and process models, best-practice guidelines for their development, and the legal, ethical, clinical, technology, and financial issues relevant to the creation of an Irish dementia registry. Following ethical approval, we also conducted two focus groups with people with dementia and twenty-one expert stakeholder interviews with clinicians, and representatives from research, health, and social care organisations in Ireland and the UK, existing Irish patient registries, and international dementia registries. Discussions followed an agreed structure, were audio-recorded, transcribed, and analysed using inductive content analysis. Common themes that emerged from the literature review and stakeholder discussions were: registry function; registry data; benefits and risks; governance; legislation; barriers and facilitators; lessons learned; best practice; and complexities within the Irish system. Given the government strategy of addressing research and information systems as part of the 2014 National Dementia Strategy, it is opportune to examine the best approach to improving dementia data recording in Ireland. These results provide an evidence-base on which to progress this debate.

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

BackgroundDementia is a highly disabling condition causing considerable economic and societal burden worldwide. Predictions of future dementia prevalence need to take into account that, on the one hand, cardiovascular disease...

Changes in prevalence and incidence of dementia and risk factors for dementia: an analysis from cohort studies

Background: Dementia has become one of the leading causes of death across the world. Aims: The aim of this study was to investigate the incidence, prevalence, and mortality of dementia in China between 2010 and 2020, and to investigate any geographical, age, and sex differences in the prevalence and incidence of dementia. Methods: Five databases were searched. The Joanna Briggs Institute (JBI) critical appraisal tool was used to assess the quality of the included studies. A random-effects meta-analysis was performed to estimate the pooled prevalence of dementia. Subgroup analysis was based on the type of dementia. The incidence and mortality of dementia were synthesized qualitatively. Results: A total of 19 studies were included. The meta-analysis showed that the prevalence of dementia was 6% (95%CI 5%, 8%), the prevalence of Alzheimer’s disease (AD) was 5% (95%CI 4%, 6%), and the prevalence of vascular dementia (VaD) was 1% (95%CI 0%, 2%). The subgroup analysis showed that the prevalence rates of dementia in rural (6%, 95%CI 4%, 8%) and urban areas were similar (6%, 95%CI 4%, 8%). Deaths due to dementia increased over time. Conclusion: The prevalence, incidence, and mortality of dementia increased with age and over time. Applying consistent criteria to the diagnosis of cognitive impairment and dementia is necessary to help with disease monitoring. Promoting dementia knowledge and awareness at the community level is necessary.

Recent studies suggest a decline in the age-specific incidence and prevalence of dementia. However, results are mixed regarding trends among octogenarians. We investigated time trends in the prevalence and incidence of dementia in 3 population-based cohorts of 85-90-year olds. We also examined if there were different time trends for men and women. We examined population-based birth cohorts within the Gothenburg H70 Birth Cohort Studies born 1901-02, 1923-24, and 1930, at ages 85 (N=1481) and 88 (N=840) years. The first 2 cohorts were also examined at age 90 (N=450). The incidence was examined in 1109 individuals free from dementia at baseline using information from the examination at age 88 or register data. All 3 cohorts were examined with identical methods. The prevalence of dementia decreased from 29.8% in 1986-87 to 21.5% in 2008-10 and 24.5% in 2015-16 among 85-year olds, and from 41.9% in 1989-90 to 28.0% in 2011-12 to 21.7% in 2018-19 among 88-year olds, and from 41.5% in 1991-92 to 37.2% in 2013-14 among 90-year olds. The decline was most accentuated among women. The incidence of dementia per 1000 risk-years from ages 85 to 89 declined from 48.8 among those born 1901-02 to 37.9 in those born 1923-24 to 22.5 among those born 1930. The prevalence and incidence of dementia decreased substantially over 3 decades among octogenarians. This might slow down the projected increase in cases of dementia expected by the increasing number of octogenarians during the following decades.

Few studies have shown that an increased risk of dementia is associated with diabetes mellitus. To estimate the prevalence and incidence of dementia in people with diabetes in primary care in the UK. We conducted a descriptive study using the UK The Health Improvement Network (THIN) database. People diagnosed with diabetes from 2000 to 2016 were included in the study. Prevalence and incidence rates of dementia were calculated annually, stratified by age and gender. The prevalence of dementia was 0.424% [95% CI (0.420%-0.427%)] in 2000 and 2.508% [95% CI (2.501%-2.515%)] in 2016. The highest prevalence was in those aged 85+ from 2.9% [95% CI (2.890%-2.974%)] in 2000 to 11.3% [95% CI (11.285%-11.384%)] in 2016. The incidence of dementia increased 3.7 times, from 0.181 cases per 100 persons [95% CI (0.179-0.183)] in 2000 to 0.683 cases per 100 persons [95% CI (0.679-0.686)] in 2016, respectively. Women had a higher prevalence and incidence of dementia than men 3.138% [95% CI (3.127%-3.150%)] versus 2.014% [95% CI (2.006%-2.022%)] and 0.820 [95% CI (0.814-0.826)] versus 0.576 cases per 100 persons [95% CI (0.571-0.580)] in 2016, respectively. There was a trend of increasing prevalence and incidence of dementia in people with diabetes over the period of 2000 to 2016. This study adds to the evidence on dementia prevalence and incidence, particularly in the diabetic population.

BackgroundFew population‐based prospective studies have investigated whether the prevalence, incidence, and survival rate of dementia in a community have changed since the 2010s.MethodSeven cross‐sectional surveys of dementia were conducted among residents of a Japanese community, aged ≥65 years, in 1985, 1992, 1998, 2005, 2012, 2017, and 2022. We also established three cohorts consisting of the residents of this age group without dementia in 1988 (n = 803), 2002 (n = 1,231), and 2012 (n = 1,521) and each was followed for 10 years. Trends in the prevalence of dementia were tested by using the logistic regression model. The age‐ and sex‐adjusted incidence and survival rate of dementia were compared between cohorts using the Cox proportional hazards model.ResultThe crude prevalence of dementia increased with time from 1985 to 2012 (6.7% in 1985, 5.7% in 1992, 7.1% in 1998, 12.5% in 2005, and 17.9% in 2012, p for trend <0.01), while the crude prevalence of dementia decreased with time from 2012 to 2022 (17.9% in 2012, 15.6% in 2017, and 11.9% in 2022, p for trend <0.01). These secular changes did not change even after standardizing by age. The age‐ and sex‐adjusted incidence of dementia significantly increased from the 1988 cohort to the 2002 cohort (adjusted hazard ratio [aHR] = 1.7, 95% confidence intervals [CI] = 1.4‐2.1). However, the age‐ and sex‐adjusted incidence of dementia significantly decreased from the 2002 cohort to 2012 cohort (aHR = 0.6, 95% CI = 0.5‐0.7). The age‐ and sex‐adjusted 5‐year survival rate of dementia significantly improved from the 1988 cohort to the 2002 cohort (47.3% to 65.2%, p<0.01), while no secular change was observed from the 2002 cohort to the 2012 cohort (65.2% to 58.3%, p = 0.39).ConclusionThe decreasing trends in the prevalence and incidence of dementia were observed since 2012 in the Japanese older population. The decline in the incidence of dementia may be due to prevention of lifestyle‐related diseases, such as hypertension and diabetes, and improvement of proper management of the disease, as well as awareness and promotion of healthy lifestyle behaviors.

Little is known about the prevalence and incidence of dementia in Aboriginal communities in Canada. As with the Canadian population, dementia in Aboriginal people is expected to be an increasing challenge for federal, provincial and community health care systems. To respond to a dearth of information concerning the prevalence of dementia in First Nations, this paper reports population-level data on dementia in the First Nations population in Alberta, Canada. Aggregate data obtained from Alberta Health and Wellness were analyzed. Physician-treated prevalence rates for dementia were calculated for First Nations and non-First Nations populations seeking treatment in Alberta (1998-2009). Trends in age-adjusted rates over time were compared using linear regression models. Age and sex effects were also examined. In 2009, the age-standardized prevalence of dementia in First Nations in Alberta was 7.5 per 1,000 (95% CI: 6.6 to 8.5 per 1,000) compared to non-First Nations, at 5.6 per 1,000 (95% CI: 5.5 to 5.6). The prevalence of dementia rose more quickly for First Nations (p=0.032). The data suggest that dementia disproportionately affects younger age groups and males (p=0.017) in First Nations populations compared to non-First Nations. Dementia represents an emerging health concern for First Nations. This increase may be driven by parallel trends, such as population aging, changing perceptions of dementia, and disproportionately higher rates of associated risk factors, impacts of the social determinants of health, and co-morbid illnesses. The unique epidemiological profile supports the need for responsive policies, programs and care geared specifically to First Nations.

Few population-based studies have investigated how the prevalence, incidence, and survival rate of dementia have changed since the 2010s in Asian communities. We investigated this issue using 37 years of epidemiological data in a Japanese community. Seven cross-sectional surveys of dementia were conducted among residents aged ≥ 65 years in a Japanese community in 1985, 1992, 1998, 2005, 2012, 2017, and 2022. We also established three cohorts in the residents aged ≥ 65 years without dementia in 1988 (n = 803), 2002 (n = 1,231), and 2012 (n = 1,519), each of which was followed for 10 years. Trends in the prevalence of dementia were tested using a logistic regression model. The age- and sex-adjusted incidence of dementia and survival rate after dementia onset were compared across cohorts using a Cox proportional hazards model. The crude prevalence of dementia significantly increased from 1985 to 2012 (6.7% in 1985, 5.7% in 1992, 7.1% in 1998, 12.5% in 2005, and 17.9% in 2012, p for trend < 0.01), but then decreased significantly from 2012 to 2022 (15.8% in 2017 and 12.1% in 2022; p for trend < 0.01). A similar trend was observed after adjusting for age and sex. Moreover, the age- and sex-adjusted incidence of dementia increased significantly from the 1988 to the 2002 cohort (adjusted hazard ratio [aHR] 1.68, 95% confidence intervals [CI] = 1.38-2.06), but decreased significantly from the 2002 to the 2012 cohort (aHR = 0.60, 95% CI = 0.51-0.70). The age- and sex-adjusted 5-year survival rate after dementia onset increased significantly from the 1988 to the 2002 cohort (47.3% to 65.2%; p < 0.01), while no significant change was observed from the 2002 to the 2012 cohort (65.2% to 58.9%; p = 0.42). Decreasing trends in the prevalence and incidence of dementia were observed since 2012 in a Japanese community. The decline in the incidence of dementia may be due to the prevention and improved management of lifestyle-related diseases, such as hypertension and diabetes, as well as increased awareness and promotion of healthy lifestyle behaviors.

ABSTRACTBackgroundUnderstanding the prevalence and risk of dementia in homeless adults has important implications for ensuring appropriate resources are directed towards dementia prevention and healthy aging. We aimed to estimate the: (1) prevalence and (2) risk of dementia among homeless adults, and (3) risk of homelessness in adults experiencing dementia.MethodsA systematic search was completed in MEDLINE, PsycINFO, Embase, CINAHL, Cochrane Central, Social Works s, and the gray literature from inception to September 26, 2024. Studies investigating the prevalence of dementia among individuals experiencing homelessness aged 18 years or older were included. Title, abstract, and full text screening, extraction, and risk of bias assessments were completed in duplicate. Random effects meta‐analysis using generalized linear mixed models was used to estimate the prevalence of dementia. For the risk and incidence of dementia, we meta‐analyzed the risk and hazards of dementia comparing homeless to housed individuals.ResultsA total of 1585 citations were retrieved, with 102 studies undergoing full‐text review. Thirty‐six studies were included in the final review (504,766 individuals experiencing homelessness, with the following weighted by sample size: mean age 63.08, female percentage 10.64). The prevalence of dementia was 6.81% (95% CI: 4.49, 10.19%, I2 = 99.7%). Among those who experienced homelessness compared to housed individuals, the risk ratio for dementia was 1.03 (95% CI: 0.52, 2.03, I2 = 99.7%), and the incidence (hazard ratio) for dementia was 1.54 (0.52, 4.50, I2 = 98.0%). One study showed that a younger age was associated with homelessness among adults with dementia.ConclusionsThis systematic review and meta‐analysis suggests that homeless individuals have a dementia prevalence higher than population‐based studies of housed adults of a similar age, where the estimated prevalence is under 3%. Research on models of care aimed at reducing homelessness in those experiencing dementia is needed.Trial RegistrationPROSPERO: CRD42024595047

Older residents in public housing represent a particularly vulnerable population at risk for cognitive decline due to their disadvantaged socioeconomic and health-related characteristics which are well-known risk factors of dementia. This study aims to synthesize available evidence regarding the prevalence of dementia and cognitive impairment among public senior housing residents. We conducted a literature search for studies published in English in the following databases: PsychInfo, PubMed, MEDLINE, CINAHL, and The Cochrane Library. We focused on observational studies about residents of public senior housings that reported prevalence and/or incidence of dementia and/or cognitive impairment screened by assessment tools for detecting dementia equivalent cognitive impairment. A total of ten studies were included for a meta-analysis to estimate the overall prevalence of cognitive impairment and dementia. Seven of ten studies utilized screening tools to detect dementia equivalent cognitive impairment. Overall pooled prevalence of cognitive impairment or dementia was 20.4% (95%CI: 14.1-27.5). The subgroup analyses revealed the pooled prevalence of cognitive impairment among residents of public senior housing was 25.5% (95%CI: 22.0-29.1) and pooled prevalence of dementia was 13.5% (95%CI: 8.3-19.7). The subgroup findings suggest the prevalence of dementia may be higher among residents of public senior housing compared to their peers in non-public housing. Also, this population may be particularly susceptible to an unrecognized or delayed diagnosis of dementia due to the lack of formal detection strategies in public senior housing. More resources should be allocated for detection to ensure better support the residents.