INTRODUCTION This study examined the latent cognitive structure of the 10/66 Dementia Research Group protocol and assessed its psychometric properties in culturally diverse older adults in Latin America and the Caribbean.METHODS Data from 10,838 adults aged 65+ across five countries were analyzed. Confirmatory factor analyses tested unidimensional and multidimensional models representing major cognitive domains. Model fit, reliability, and a hierarchical second-order structure were examined. Measurement invariance was assessed across normative and non-normative subsamples and gender.RESULTS A multidimensional structure emerged, comprising memory, orientation, executive functioning, semantic/language, and visuospatial domains, along with a higher-order global cognition factor. Most domains demonstrated adequate fit and acceptable reliability. The second-order model provided the best overall fit. Invariance was supported across all groups tested.DISCUSSION This study provides the first empirical validation of the 10/66 protocol's latent structure, enabling the derivation of standardized cognitive scores and strengthening its utility for harmonized dementia research in diverse cultural settings.

Importance:Reliable estimates of dementia prevalence trends are essential for health policy planning. Latin America is undergoing rapid population aging, yet it remains unclear whether dementia prevalence mirrors declining patterns reported in high-income countries. Objective:To examine 2-decade trends in dementia prevalence across 5 Latin American and Caribbean sites participating in the 10/66 Dementia Research Group. Design, Setting, and Participants:This cross-sectional, population-based study included data from 5 population-based catchment areas participating in the 10/66 study: Cuba, the Dominican Republic, Mexico, Peru, and Puerto Rico. Data were collected at 2 time points: 2003 to 2006 and 2016 to 2020. Participants were community-dwelling adults aged 65 years or older, identified through exhaustive door-to-door enumeration across 2 survey waves. Data were analyzed between March 2025 and May 2026. Exposures:Survey wave (2003-2006 vs 2016-2020) was the primary temporal comparison. Secondary exposures included modifiable dementia risk factors from the Lancet Commission on dementia prevention. Main Outcomes and Measures:The main outcome was crude and age- and sex-standardized dementia prevalence using the 10/66 dementia diagnostic algorithm. Adjusted prevalence differences between waves were estimated using Poisson regression with sequential adjustment for education, health behaviors, and health risk factors. Results:Of 23 709 eligible individuals identified, 5892 declined or could not be traced and 17 817 were assessed. After excluding participants with missing dementia diagnosis or data, the analytic sample included 16 950 participants (wave 1: n = 10 374; wave 3: n = 6576; mean [SD] age, 76.0 [7.5] years; 63.7% women). Pooled crude prevalence increased from 10.6% (95% CI, 10.0%-11.2%) at 2003 to 2006 to 16.9% (95% CI, 15.9%-17.8%) at 2016 to 2020. After age and sex standardization to 2025 United Nations population structures, prevalence remained stable in Cuba and the Dominican Republic but increased substantially in Mexico (4.9 percentage points [pp]; 95% CI, 3.0-6.8 pp), Peru (4.1 pp; 95% CI, 1.9-6.4 pp), and Puerto Rico (5.0 pp; 95% CI, 1.8-8.2 pp). Increasing trends in Mexico (adjusted difference: 6.3%; 95% CI, 4.1%-8.5%) and Puerto Rico (7.2%; 95% CI, 3.8%-10.6%) persisted after full adjustment for health behaviors and risk factors. Conclusions and Relevance:This study found that dementia prevalence has increased over 2 decades across several Latin American 10/66 catchment sites, contrasting with declining trends reported in high-income countries. These findings, while specific to the 5 studied sites, highlight the growing and uneven burden of dementia in the region and underscore the need for strengthened surveillance, risk reduction strategies, and investment in dementia care infrastructure.

Alzheimer’s disease and related dementias (ADRD) disproportionately affect Latinos compared to non-Latino whites. Leveraging the non-monolithic structure of Latin America, which represents a large variability in social determinants of health (SDoH) and high levels of genetic admixture, we aimed to determine contributors to ADRD disparities within Latinos, focusing on genetic ancestry and SDoH. Community-dwelling participants aged 65 and older (n = 4000) from Cuba, Dominican Republic, Mexico, and Peru completed the 10/66 protocol assessments, including sociodemographic and risk factors questionnaire, neurological exam, cognitive assessment, and blood draw. Dementia was diagnosed using the cross-culturally validated 10/66 algorithm. Individual admixture proportions were determined using sixty ancestry-informative markers. To evaluate the effect of global ancestry on dementia and cognitive performance, we used multivariate linear regression models adjusted for SDoH (e.g., gender, education level, socioeconomic status (SES), rural area, and vascular risk factors). We observed extensive three-way (African/European/Native American) genetic ancestry variation between countries (Figure 1). Individuals with higher proportions of Native American (>70%) and African American (>70%) ancestry were more likely to exhibit factors contributing to worse SDoH, such as lower educational levels (p < 0.001), lower SES (p < 0.001), and higher frequency of vascular risk factors (p < 0.001). As a result, in unadjusted analysis, individuals with predominant African ancestry exhibited a higher dementia frequency (p = 0.03) and both Native American and African ancestry predominant groups showed lower cognitive performance relative to those with higher European ancestry (p<0.001). However, after adjusting for measures of SDoH, there was no association between ancestry proportion and dementia probability, and ancestry proportions no longer significantly accounted for the variance in cognitive performance (African predominant p = 0.31 [-0.19, 0.59] and Native predominant p = 0.74 [-0.24, 0.33]). We report a comprehensive characterization of the role of global genetic ancestry in cognitive performance and dementia in Latin America while controlling for SDoH. In our study, adjustment of SDoH attenuated associations between genetic ancestry, dementia probability, and cognitive performance. These findings highlight that social and environmental factors likely play more critical roles than genetic ancestry in determining racial/ethnic disparities in cognitive performance and subsequent dementia risk.

INTRODUCTION:Leveraging the nonmonolithic structure of Latin America, which represents a large variability in social determinants of health (SDoH) and high levels of genetic admixture, we aim to evaluate the relative contributions of SDoH and genetic ancestry in predicting dementia prevalence in Latin American populations. METHODS:Community-dwelling participants aged 65 and older (N = 3808) from Cuba, Dominican Republic, Mexico, and Peru completed the 10/66 protocol assessments. Dementia was diagnosed using the cross-culturally validated 10/66 algorithm. Multivariate linear regression models adjusted for SDoH were used in the main analysis. This study used cross-sectional data from the 1066 population-based study. RESULTS:Individuals with higher proportions of Native American (>70%) and African American (>70%) ancestry were more likely to exhibit factors contributing to worse SDoH, such as lower educational levels (p < 0.001), lower socioeconomic status (p < 0.001), and higher frequency of vascular risk factors (p < 0.001). After adjusting for measures of SDoH, there was no association between ancestry proportion and dementia probability, and ancestry proportions no longer significantly accounted for the variance in cognitive performance (African predominant p = 0.31 [-0.19, 0.59] and Native predominant p = 0.74 [-0.24, 0.33]). DISCUSSION:The findings suggest that social and environmental factors play a more crucial role than genetic ancestry in predicting dementia prevalence in Latin American populations. This underscores the need for public health strategies and policies that address these social determinants to effectively reduce dementia risk in these communities. HIGHLIGHTS:Countries in Latin America express a large variability in social determinants of health and levels of admixture. After adjustment for downstream societal factors linked to SDoH, genetic ancestry shows no link to dementia. Population ancestry profiles alone do not influence cognitive performance. SDoH are key drivers of racial disparities in dementia and cognitive performance.

Background: Little is known about the relationship between parkinsonism or Parkinson's disease (PD) and frailty in Latin America. Objective: The study aimed to determine the cross-sectional and prospective associations between parkinsonism and PD with frailty in a large multi-country cohort in Latin America. Frailty was assessed using three different models to explore which definitions are more appropriate to screen for frailty in a PD population. Methods: 12,865 older adults (aged >= 65 years) from the 10/66 population-based cohort study in six Latin American countries were analyzed. Logistic regression models assessed the cross-sectional association between parkinsonism/PD with baseline frailty. Individual country analyses were combined via fixed-effect meta-analysis. In non-frail participants who were followed up for 4 years, Cox proportional hazards regression models assessed the prospective association between parkinsonism/PD with incident frailty accounting for competing risk of mortality. Results: At baseline, the prevalence of parkinsonism and PD was 7% and 2%, respectively, and the prevalence of frailty varied across the three models with rates of 18% for frailty phenotype, 20% for frailty index and 30% for multidimensional frailty model. PD was associated with baseline and incident frailty after accounting for age, sex, and education: odds ratios and 95% confidence intervals (95% CI) for frailty were 2.49 (95% CIs 1.87-3.31), 2.42 (95% CIs 1.80-3.25), and 1.57 (95% CIs 1.16-2.21), and cause-specific hazard ratios were 1.66 (95% CIs 1.07-2.56), 1.78 (95% CIs 1.05-3.03), and 1.58 (95% CIs 0.91-2.74). Similar results were found for parkinsonism. Conclusion: Parkinsonism and PD were cross-sectionally and prospectively associated with frailty in Latin America. Routine screening for frailty in PD patients may aid earlier detection of those at greater risk of adverse outcomes.

Background: Little is known about the burden of parkinsonism and Parkinson’s disease (PD) in Latin America. Better understanding of health service use and clinical outcomes in PD is needed to improve its prognosis. Objective: The aim of the study was to estimate the burden of parkinsonism and PD in six Latin American countries. Methods: 12,865 participants aged 65 years and older from the 10/66 population-based cohort study were analysed. Baseline assessments were conducted in 2003–2007 and followed-up 4 years later. Parkinsonism and PD were defined using current clinical criteria or self-reported diagnosis. Logistic regression models assessed the association between parkinsonism/PD with baseline health service use (community-based care or hospitalisation in the last 3 months) and Cox proportional hazards regression models with incident dependency (subjective assessment by interviewer based on informant interview) and mortality. Separate analyses for each country were combined via fixed effect meta-analysis. Results: At baseline, the prevalence of parkinsonism and PD was 7.9% (n = 934) and 2.6% (n = 317), respectively. Only parkinsonism was associated with hospital admission at baseline (OR 1.89, 95% CI 1.30–2.74). Among 7,296 participants without dependency at baseline, parkinsonism (HR 2.34, 95% CI 1.81–3.03) and PD (2.10, 1.37–3.24) were associated with incident dependency. Among 10,315 participants with vital status, parkinsonism (1.73, 1.50–1.99) and PD (1.38, 1.07–1.78) were associated with mortality. The Higgins I2 tests showed low to moderate levels of heterogeneity across countries. Conclusions: Our findings show that older people with parkinsonism or PD living in Latin America have higher risks of developing dependency and mortality but may have limited access to health services.

Population ageing will lead to a dramatic increase in dementia prevalence globally. Recent evidence suggest a decline in dementia incidence in High Income Countries due to increasing education levels and improvements in cardiovascular health. Although, most of the increase will occur in low and middle-income countries (LMICs), there are no recent estimates of dementia prevalence and incidence in LMICs. The present study aimed to examine new trends on dementia prevalence and incidence in Latin-America and associations of socioeconomic determinants and cardiovascular risk factors. Sample size included older adults from Latin America (Cuba, Dominican Republic [DR], Puerto Rico [PR], and Mexico) drawn from the 10/66 Dementia Research Group study. We compare wave 1 (2003-2006) with wave 3 (2016-2019) of 10/66 studies. The main outcome was dementia prevalence relative to previous waves. Dementia diagnosis was determined according to 10/66 dementia criteria. All the 10/66 waves used the same standardized assessments and protocols. Dementia prevalence is stable Cuba, standardized dementia prevalence rates was 12.4% in wave I and 10.1% in wave III. Relative to wave I, Dominican Republic (wave I 11.5% vs wave II 13.6%), Peru (wave I 9.2% vs wave II 16.8%) and Mexico (wave 1 8.3% vs wave 2 17.1%) experience a significant increase in dementia prevalence. Despite, improvements in levels of education, increases in dementia prevalence were associated with higher rates of cardiovascular disease and cardiovascular risk factors, including diabetes, hypertension, obesity and heart disease in the later-born cohorts. Self-reported stroke is also rising. The prevalence of dementia in the older Latin American and Caribbean population is high and increasing relative to the previous decade. These findings may inform health promotion efforts within dementia national plans adopted recently in some Latin American countries

BACKGROUND:Neuropsychiatric symptoms (NPSs) are common in neurodegenerative diseases; however, little is known about the prevalence of NPSs in Hispanic populations. METHODS:Using data from community-dwelling participants age 65 years and older enrolled in the 10/66 study (N = 11,768), we aimed to estimate the prevalence of NPSs in Hispanic populations with dementia, parkinsonism, and parkinsonism-dementia (PDD) relative to healthy aging. The Neuropsychiatric Inventory Questionnaire (NPI-Q) was used to assess NPSs. RESULTS:NPSs were highly prevalent in Hispanic populations with neurodegenerative disease; approximately 34.3%, 56.1%, and 61.2% of the participants with parkinsonism, dementia, and PDD exhibited three or more NPSs, respectively. NPSs were the major contributor to caregiver burden. DISCUSSION:Clinicians involved in the care of elderly populations should proactively screen for NPSs, especially in patients with parkinsonism, dementia, and PPD, and develop intervention plans to support families and caregivers. Highlights Neuropsychiatric symptoms (NPSs) are highly prevalent in Hispanic populations with neurodegenerative diseases. In healthy Hispanic populations, NPSs are predominantly mild and not clinically significant. The most common NPSs include depression, sleep disorders, irritability, and agitation. NPSs explain a substantial proportion of the variance in global caregiver burden.

Background: Age-gender-specific prevalence rates for parkinsonism and Parkinson’s disease (PD) are important to guide research, clinical practice and public health planning; however, prevalence estimates in Latin America (LatAm) are limited. We aimed to estimate the prevalence of parkinsonism and PD and examine its risk factors in a cohort of elderly individuals from LatAm.Methods: Data from 11,613 adults (65+ years) who participated in a baseline assessment of the 10/66 study and who lived in six LatAm countries were analyzed to estimate Parkinsonism and PD prevalence. Crude and age-adjusted prevalence were determined by sex and country. Diagnosis of PD was established using the UK Parkinson’s Disease Society Brain Bank’s clinical criteria.Findings: In this cohort, the prevalence of Parkinsonism was 8.0% (95% CI 7.6%-8.5%), and the prevalence of PD was 2.0% (95% CI 1.7%-2.3%). PD prevalence increased with age from 1.0 to 3.5 (65-69 vs. 80 years or older, p<0.001). Age-adjusted prevalence rates were lower for women than for men. No significant differences were found across countries, except for lower prevalence in urban areas of Peru. PD was positively associated with depression (adjusted prevalence ratio [aPR] 2.06, 95% CI 1.40-3.01, I2=56.0%), dementia (aPR 1.57, 95% CI 1.07- 2.32, I2=0.0%) and educational level (aPR 1.14, 95% CI 1.01- 1.29, I2=58.6%).Interpretation: The reported prevalence of PD in LatAm is similar to the prevalence in HIC. A significant proportion of cases with PD did not have a previous diagnosis, nor did they seek any medical or neurological attention. These findings underscore the need to improve public health programs for populations that are currently undergoing rapid demographic aging and epidemiological transition.Funding: The 10/66 Dementia Research Group’s research has been funded by the Wellcome Trust Health Consequences of Population Change Program (GR066133 – Prevalence phase in Cuba and Brazil; GR080002- Incidence phase in Peru, Mexico, Argentina, Cuba, Dominican Republic, Venezuela, and China).Declaration of Interest: None to declare. Ethical Approval: This project was approved by local institutional review boards and the King’s College London Research Ethics Committee.

INTRODUCTION:Apolipoprotein E (APOE) is considered the major susceptibility gene for developing Alzheimer's disease. However, the strength of this risk factor is not well established across diverse Hispanic populations. METHODS:We investigated the associations among APOE genotype, dementia prevalence, and memory performance (immediate and delayed recall scores) in Caribbean Hispanics (CH), African Americans (AA), Hispanic Americans (HA) and non-Hispanic White Americans (NHW). Multivariable logistic regressions and negative binomial regressions were used to examine these associations by subsample. RESULTS:Our final dataset included 13,516 participants (5198 men, 8318 women) across all subsamples, with a mean age of 74.8 years. Prevalence of APOE ε4 allele was similar in CHs, HAs, and NHWs (21.8%-25.4%), but was substantially higher in AAs (33.6%; P < 0.001). APOE ε4 carriers had higher dementia prevalence across all groups. DISCUSSION:APOE ε4 was similarly associated with increased relative risk of dementia and lower memory performance in all subsamples.

Latin America and the Caribbean (LAC) countries are experiencing unprecedentedly rapid demographic ageing. Growing evidence shows that cardiovascular health (CVH) is associated with brain health. Little is known about this topic among older adults in Latin America, where the number of people living with dementia is rising. The present study aimed to examine the prevalence, incidence and associations of socioeconomic determinants and cardiovascular risk factors with dementia across six LAC countries. The 10/66 Dementia Research Group has carried out population-based catchment area surveys, using a common protocol, in six Latin-American countries Cuba, Dominican Republic, Mexico, Peru, Puerto Rico and Venezuela of all over 65 year old (n = 12 704). An incidence wave was conducted 4 -5 years after cohort inception, 8 502 participants were reinter viewed, contributing 34 000 person-years of follow-up. The outcomes were 10/66 dementia and DSM IV dementia. An index of modifiable CVH factors (ranging from 0 to 14) was calculated. Incident dementia was modeled using competing risks regression to adjust for risk of death. The prevalence of dementia varied widely across different countries, ranging from 4.8% in Peru and 11.7% in Puerto Rico and the Dominican Republic. Incidence of 10/66 dementia varied between 18.2 (95% CI 14.3-23.0) per 1000 person-years in Peru to 30.4 (25.5-36.3) per 1000 person-years in Mexico. Being male, having higher education and younger age were all protective of dementia. Specific cognitive tests including literacy, verbal fluency and motor sequencing had also similar protective associations with dementia, providing more supporting evidence for the cognitive reserve hypothesis. Compared to poor CVH, participants with moderate and ideal levels of CVH had a significantly lower risk of dementia both in the unadjusted (subhazard ratio for moderate: 0.77; ideal: 0.59) and adjusted models (moderate: 0.73; ideal: 0.66). The prevalence of dementia in the older Latin American and Caribbean population is high. Moderate and ideal levels of CVH in old age may protect against dementia incidence. These findings may inform health promotion efforts within dementia national plans adopted recently in some Latin American countries