Nine potentially modifiable risk factors (less childhood education, midlife hearing loss, hypertension, and obesity, and later-life smoking, depression, physical inactivity, social isolation, and diabetes) account for 35% of worldwide dementia, but most data to calculate these risk factors come from high-income countries only. We aimed to calculate population attributable fractions (PAFs) for dementia in selected low-income and middle-income countries (LMICs) to identify potential dementia prevention targets in these countries. The study was an analysis of cross-sectional data obtained from the 10/66 Dementia Research surveys of representative populations in India, China, and six Latin America countries (Cuba, Dominican Republic, Mexico, Peru, Puerto Rico, and Venezuela), which used identical risk factor ascertainment methods in each country. Between 2004 and 2006 (and between 2007 and 2010 for Puerto Rico), all residents aged 65 years and older in predefined catchment areas were invited to participate in the survey. We used risk factor prevalence estimates from this 10/66 survey data, and relative risk estimates from previous meta-analyses, to calculate PAFs for each risk factor. To account for individuals having overlapping risk factors, we adjusted PAF for communality between risk factors, and used these values to calculate overall weighted PAFs for India, China, and the Latin American sample. The overall weighted PAF for potentially modifiable risk factors for dementia was 39·5% (95% CI 37·5-41·6) in China (n=2162 participants), 41·2% (39·1-43·4) in India (n=2004), and 55·8% (54·9-56·7) in our Latin American sample (n=12 865). Five dementia risk factors were more prevalent in these LMICs than worldwide estimates, leading to higher PAFs for dementia: less childhood education (weighted PAF of 10·8% in China, 13·6% in India, and 10·9% in Latin America vs 7·5% worldwide), smoking (14·7%, 6·4%, and 5·7%, respectively, vs 5·5% worldwide), hypertension (6·4%, 4·0%, and 9·3%, vs 2·0%), obesity (5·6%, 2·9%, and 7·9%, vs 0·8%), and diabetes (1·6%, 1·7%, and 3·2%, vs 1·2%). The dementia prevention potential in India, China, and this sample of Latin American countries is large, and greater than in high-income countries. Less education in early life, hypertension, hearing loss, obesity, and physical inactivity have particularly high PAFs and could be initial targets for dementia prevention strategies. No funding.

Some cohort studies have reported a decline in dementia prevalence and incidence over time, although these findings have not been consistent across studies. We reviewed evidence on changes in dementia prevalence and incidence over time using published population-based cohort studies that had used consistent methods with each wave and aimed to quantify associated changes in risk factors over time using population attributable fractions (PAFs). We searched for systematic reviews of cohort studies examining changes in dementia prevalence or incidence over time. We searched PubMed for publications from database inception up to Jan 12, 2023, using the search terms "systematic review" AND "dementia" AND ("prevalence" OR "incidence"), with no language restrictions. We repeated this search on March 28, 2024. From eligible systematic reviews, we searched the references and selected peer-reviewed publications about cohort studies where dementia prevalence or incidence was measured in the same geographical location, at a minimum of two timepoints, and that reported age-standardised prevalence or incidence of dementia. Additionally, data had to be from population-based samples, in which participants' cognitive status was assessed and where validated criteria were used to diagnose dementia. We extracted summary-level data from each paper about dementia risk factors, contacting authors when such data were not available in the published paper, and calculated PAFs for each risk factor at all available timepoints. Where possible, we linked changes in dementia prevalence or incidence with changes in the prevalence of risk factors. We identified 1925 records in our initial search, of which five eligible systematic reviews were identified. Within these systematic reviews, we identified 71 potentially eligible primary papers, of which 27 were included in our analysis. 13 (48%) of 27 primary papers reported change in prevalence of dementia, ten (37%) reported change in incidence of dementia, and four (15%) reported change in both incidence and prevalence of dementia. Studies reporting change in dementia incidence over time in Europe (n=5) and the USA (n=5) consistently reported a declining incidence in dementia. One study from Japan reported an increase in dementia prevalence and incidence and a stable incidence was reported in one study from Nigeria. Overall, across studies, the PAFs for less education or smoking, or both, generally declined over time, whereas PAFs for obesity, hypertension, and diabetes generally increased. The decrease in PAFs for less education and smoking was associated with a decline in the incidence of dementia in the Framingham study (Framingham, MA, USA, 1997-2013), the only study with sufficient data to allow analysis. Our findings suggest that lifestyle interventions such as compulsory education and reducing rates of smoking through country-level policy changes could be associated with an observed reduction, and therefore future reduction, in the incidence of dementia. More studies are needed in low-income and middle-income countries, where the burden of dementia is highest, and continues to increase. National Institute for Health and Care Research Three Schools' Dementia Research Programme.

Over the past decades European societies have become increasingly diverse. This diversity in culture, education, and language significantly impacts neuropsychological assessment. Although several i...

Background: Bilingualism may contribute to cognitive reserve, protect against cognitive decline, and delay the onset of dementia. Objective: We systematically reviewed evidence about the effect of bilingualism on subsequent cognitive decline or demen

Only a minority of people with dementia receive a formal diagnosis despite a growing body of evidence highlighting the benefits of early diagnosis and intervention. People from minority ethnic groups are even more disadvantaged, as they tend to access dementia services later in the illness. Studies exploring the reasons behind underuse of dementia services by minority ethnic groups have highlighted the barriers to help-seeking that seem specific to the cultural groups studied. Understanding the barriers to help-seeking should help to identify the targets for interventions to encourage help-seeking in minority ethnic communities. This review sought to highlight the progress in this field and show what interventions have been developed so far. Many countries are carrying out educational campaigns in an effort to increase awareness about dementia and reduce stigma, but none of these have reported any measurable outcomes of their interventions. Studies show that knowledge about dementia has the potential to increase help-seeking, but information should be targeted to the recipient audience. Not enough has been done to address the inequality in service use for dementia in minority ethnic groups compared with the majority population. The time has come for the development of targeted and evidence-based interventions in order to improve access and affect outcomes.

The potential economic value of interventions to prevent late-onset dementia is unknown. We modelled this for potentially modifiable risk factors for dementia. For this modelling study, we searched PubMed and Web of Science from inception to March 12, 2020, and included interventions that: successfully targeted any of nine prespecified potentially modifiable risk factors (hypertension, diabetes, hearing loss, obesity, physical inactivity, social isolation, depression, cigarette smoking, and less childhood education); had robust evidence that the intervention improved risk or risk behaviour; and are feasible to enact in an adult population. We established when in the life course each intervention would be delivered. We calculated dementia incidence reduction from annual incidence of dementia in people with each risk factor, and population attributable fraction for each risk, corrected for risk factor clustering, and how effectively the intervention controls the risk factor. We calculated the discounted value of lifetime health gain and effect on cost (including NHS, social care and carer costs) per person eligible for treatment. We estimated annual total expenditure on the fully operational intervention programme in England. We found effective interventions for hypertension, smoking cessation, diabetes prevention, and hearing loss. Treatments for stopping smoking and provision of hearing aids reduced cost. Treatment of hypertension was cost-effective by reference to standard UK thresholds. The three interventions when fully implemented would save £1·863 billion annually in England, reduce dementia prevalence by 8·5%, and produce quality-adjusted life-year gains. The intervention for diabetes was unlikely to be cost-effective in terms of effect on dementia alone. There is a strong case for implementing the three effective interventions on grounds of cost-effectiveness and quality-of-life gains, as well as for improvements in general health. The interventions have the potential to remain cost-saving or cost-effective even with variations in dementia incidence and costs and effectiveness of interventions. Economic and Social Research Council.