The prevalence of dementia subtypes in rural Tanzania

Prevalence and risk factors for Alzheimer's disease and related dementias in Ghana: Evidence from a cross-sectional population-based study

Alzheimer's disease and Related Dementia (ADRD) is a growing concern for low- and middle-income countries. Yet, studies on the prevalence and risk factors for dementia in sub-Saharan Africa are limited. This study estimated the prevalence and identified the risk factors for ADRD in Ghana. A cross-sectional design involving 384 participants aged 60 years or more completed the Brief Community Screening Instrument for Dementia (CSID) with an additional set of questions on risk factors. The prevalence of dementia was 16% (62/384). Age (AOR = 1.031 (95% CI 1.002-1.061, p=0.035), education (AOR = 0.689 (95% CI 0.517-0.919, p=0.011), and employment (AOR = 0.320 (95% CI 0.149-0.685, p=0.004) were associated with dementia. Also, "experience of stressful life event from age 16-64" (AOR = 1.325 (95% CI 1.034-1.698, p=0.024), "experience of stressful life event from age 65+" (AOR = 1.258 (95% CI 1.024-1.546, p=0.042), and "activities of daily living" (AOR = 0.925 (95% CI 0.868-0.986, p=0.037) identified as risk factors of dementia. The burden of ADRD was high. Urgent actions are needed to address this problem. There is a possibility that the burden of dementia may have been overestimated because of the study instrument. Findings should be interpreted in light of this limitation.

The 2022 symposium on dementia and brain aging in low- and middle-income countries: Highlights on research, diagnosis, care, and impact

Two of every three persons living with dementia reside in low- and middle-income countries (LMICs). The projected increase in global dementia rates is expected to affect LMICs disproportionately. However, the majority of global dementia care costs occur in high-income countries (HICs), with dementia research predominantly focusing on HICs. This imbalance necessitates LMIC-focused research to ensure that characterization of dementia accurately reflects the involvement and specificities of diverse populations. Development of effective preventive, diagnostic, and therapeutic approaches for dementia in LMICs requires targeted, personalized, and harmonized efforts. Our article represents timely discussions at the 2022 Symposium on Dementia and Brain Aging in LMICs that identified the foremost opportunities to advance dementia research, differential diagnosis, use of neuropsychometric tools, awareness, and treatment options. We highlight key topics discussed at the meeting and provide future recommendations to foster a more equitable landscape for dementia prevention, diagnosis, care, policy, and management in LMICs. HIGHLIGHTS: Two-thirds of persons with dementia live in LMICs, yet research and costs are skewed toward HICs. LMICs expect dementia prevalence to more than double, accompanied by socioeconomic disparities. The 2022 Symposium on Dementia in LMICs addressed advances in research, diagnosis, prevention, and policy. The Nairobi Declaration urges global action to enhance dementia outcomes in LMICs.

Lack of Association of Vascular Risk Factors with HIV-Associated Neurocognitive Disorders in cART-Treated Adults Aged ≥ 50 Years in Tanzania

HIV-associated neurocognitive disorders (HAND) are highly prevalent in those ageing with HIV. High-income country data suggest that vascular risk factors (VRFs) may be stronger predictors of HAND than HIV-disease severity, but data from sub-Saharan Africa are lacking. We evaluated relationships of VRFs, vascular end-organ damage and HAND in individuals aged ≥ 50 in Tanzania. c-ART-treated individuals were assessed for HAND using consensus criteria. The prevalence of VRFs and end organ damage markers were measured. The independent associations of VRFs, end organ damage and HAND were examined using multivariable logistic regression. Data were available for 153 individuals (median age 56, 67.3% female). HAND was highly prevalent (66.7%, 25.5% symptomatic) despite well-managed HIV (70.5% virally suppressed). Vascular risk factors included hypertension (34%), obesity (10.5%), hypercholesterolemia (33.3%), diabetes (5.3%) and current smoking (4.6%). End organ damage prevalence ranged from 1.3% (prior myocardial infarction) to 12.5% (left ventricular hypertrophy). Measured VRFs and end organ damage were not independently associated with HAND. The only significant association was lower diastolic BP (p 0.030, OR 0.969 (0.943-0.997). Our results suggest that vascular risk factors are not major drivers of HAND in this setting. Further studies should explore alternative aetiologies such as chronic inflammation.

Cognition in older adults in Uganda: Correlates, trends over time and association with mortality in prospective population study

Dementia is an important and growing issue in sub-Saharan Africa, but epidemiological data are lacking. Risk factors may differ from other regions due to high stroke incidence and HIV prevalence. Understanding the epidemiology of cognition in older adults in Africa is crucial for informing public health strategies to improve the lives of people with dementia and their carers. The Wellbeing of Older People Study in Uganda is an open cohort of adults aged 50+ with and without HIV, established in 2009. Detailed socio-demographic and health data have been collected at four waves spanning 10 years, including cognitive assessment using internationally validated WHO-recommended tests: verbal recall, digit span, and verbal fluency. Mortality data was collected until the end of the fourth wave (2019). We examined associations of low baseline cognition scores and changes in cognition score over time using random effects modelling, care needs of people with lower cognition scores, and the relationship between cognition score and mortality. Data were collected on 811 participants. Older age, lower educational attainment, lower socio-economic position, and extremes of BMI were associated with lower cognition scores. Cognition scores declined faster at older ages, but rate of decline was not associated with cardiovascular disease or HIV at baseline. People with lower cognition scores required more assistance with Activities of Daily Living, but mortality rates were similar across the range of cognition scores. The crucial next step will be to investigate types and presentation of clinical dementia in this cohort, so we can better understand the clinical relevance of these findings to inform public health planning.

Digital phenotyping: An equal opportunity approach to reducing disparities in Alzheimer's disease and related dementia research

A rapidly aging world population is fueling a concomitant increase in Alzheimer's disease (AD) and related dementias (ADRD). Scientific inquiry, however, has largely focused on White populations in Australia, the European Union, and North America. As such, there is an incomplete understanding of AD in other populations. In this perspective, we describe research efforts and challenges of cohort studies from three regions of the world: Central America, East Africa, and East Asia. These cohorts are engaging with the Davos Alzheimer's Collaborative (DAC), a global partnership that brings together cohorts from around the world to advance understanding of AD. Each cohort is poised to leverage the widespread use of mobile devices to integrate digital phenotyping into current methodologies and mitigate the lack of representativeness in AD research of racial and ethnic minorities across the globe. In addition to methods that these three cohorts are already using, DAC has developed a digital phenotyping protocol that can collect ADRD-related data remotely via smartphone and/or in clinic via a tablet to generate a common data elements digital dataset that can be harmonized with additional clinical and molecular data being collected at each cohort site and when combined across cohorts and made accessible can provide a global data resource that is more racially/ethnically represented of the world population.

Epidemiology of neurodegenerative diseases in the East African region: A meta-analysis

INTRODUCTION

There is a scarcity of epidemiological data on neurodegenerative diseases (NDs) in East Africa. This meta-analysis provides the regional prevalence of NDs, their contributing factors, and evidence of change over time concerning gender per age or year.

METHODS

Articles were retrieved from electronic databases following the PRISMA standard.

RESULTS

Forty-two studies were reviewed, and 25 were meta-analyzed with a random-effects model. The pool estimate proportion of 15.27%, 95% CI (0.09-0.23) (I² = 98.25%), (Q = 1,369.15, p < 0.0001) among a population of 15,813 male/female and 1,257 with NDs. Epidemiological characteristics associated with NDs include Dyskinesias prevalence 55.4%, 95% CI (13.5; 90.9), I² (96%) and subsistence farming prevalence 11.3%, 95% CI (5.8; 20.9), I² (99%). Publication bias by Egger test was (z = 4.1913, p < 0.0001), while rank correlation test using Kendall's model was (tau = 0.1237, p = 0.3873). Heterogeneity (R² design = 5.23%, p design < 0.0001; R² size = 52.163%, p size < 0.001; and R² period = 48.13, p period < 0.0001. Covariates (R² design + size + period = 48.41%, p < 0.001).

CONCLUSION

There is a high prevalence of NDs in the East African region, which could impact life expectancy, morbidity, and quality of life. Thus, early screening and regular surveillance could assist in management strategies.

Osuntokun Award Lecture 2021: Challenges of Measuring the Burden of Stroke in Africa

BACKGROUND

Over recent years non-communicable diseases have dramatically increased in low- and middle-income countries, including those of sub-Saharan Africa. With continuing high levels of infectious disease, these countries now face the double burden of disease. Stroke has emerged as a major cause of hospital admission, disability, and mortality for which the major modifiable risk factor is hypertension, which is often not diagnosed and, even if diagnosed, not treated and, even if treated, not controlled.

METHODS

In this award lecture paper I outline my personal experience of measuring the burden of, and risk factors for, stroke in sub-Saharan Africa, along with the challenges faced. I will specifically describe the measurement of mortality and case fatality, prevalence and incidence as well as commenting on aetiology and risk factors and reflect on future initiatives and directions.

RESULTS

Over the past 5 decades there has been a dramatic increase in numbers of stroke patients admitted to hospital throughout sub-Saharan Africa, with high in hospital mortality rates, also reflected in high case fatality rates in those cohorts followed up following discharge from hospital. Community-based surveys assessing mortality from stroke using verbal autopsy have demonstrated very high age-adjusted rates. Age adjusted prevalence rates assessed by door-to-door surveys have generally shown lower prevalence than high income countries. The Tanzanian stroke incidence study, which incorporated verbal autopsy for those patients dying before reaching hospital, demonstrated some of the highest age-adjusted stroke incidence rates in the world. There were high rates of stroke in younger ages and high rates of intracranial haemorrhage though not as high as previously shown in hospital-based studies. Hypertension is the main modifiable risk factor but other risk factors such as HIV are important while, certainly in rural populations, raised cholesterol remains rare as does carotid artery stenosis and history of transient ischemic attack. Other vascular disease such as ischemic heart disease and peripheral vascular disease is also less common.

CONCLUSIONS

There is already a large burden relating to stroke in sub-Saharan Africa and this will only escalate further as the population ages. Hypertension is the biggest risk factor for mortality worldwide and in sub-Saharan Africa prevalence rates are very high with the majority of people suffering with stroke not being diagnosed with their hypertension prior to their stroke. The most important challenge is to improve primary prevention for which improving diagnosis and control rates for hypertension is the number one priority. For those who do have stroke there is a need to increase the number of suitably staffed stroke units as these have been shown to have a very large impact on improving both mortality and morbidity in high income countries. There are still many unanswered questions and a need for more research throughout sub-Saharan Africa on risk factors, and treatment, for stroke.

Dementia in Africa: Current evidence, knowledge gaps, and future directions

In tandem with the ever-increasing aging population in low and middle-income countries, the burden of dementia is rising on the African continent. Dementia prevalence varies from 2.3% to 20.0% and incidence rates are 13.3 per 1000 person-years with increasing mortality in parts of rapidly transforming Africa. Differences in nutrition, cardiovascular factors, comorbidities, infections, mortality, and detection likely contribute to lower incidence. Alzheimer's disease, vascular dementia, and human immunodeficiency virus/acquired immunodeficiency syndrome-associated neurocognitive disorders are the most common dementia subtypes. Comprehensive longitudinal studies with robust methodology and regional coverage would provide more reliable information. The apolipoprotein E (APOE) ε4 allele is most studied but has shown differential effects within African ancestry compared to Caucasian. More candidate gene and genome-wide association studies are needed to relate to dementia phenotypes. Validated culture-sensitive cognitive tools not influenced by education and language differences are critically needed for implementation across multidisciplinary groupings such as the proposed African Dementia Consortium.

Managing dementia in rural Nigeria: feasibility of cognitive stimulation therapy and exploration of clinical improvements

Objectives: We investigated the feasibility and clinical impact of a psychosocial intervention, Cognitive Stimulation Therapy (CST), to help manage dementia in a rural setting in Nigeria. Method: People with dementia were identified from a prevalence study in Lalupon in the south-west of Nigeria. Prior to this feasibility study CST was adapted for the setting and pilot by our team. Fourteen sessions of CST were provided over a 7-week period by a trained nurse specialist and occupational therapist. Change in quality of life was the main outcome. Results: Nine people were enrolled in CST. Significant improvements in cognitive function, quality of life (physical, psychosocial and environmental domains), physical function, neuro-psychiatric symptoms and carer burden were seen. Conclusions: CST appears to be feasible in this setting, although adaptation for low literacy levels, uncorrected visual and hearing impairment and work and social practices is needed. The clinical improvements seen were encouraging.

Cognitive Function and Impairment in Older, Rural South African Adults: Evidence from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in Rural South Africa"

BACKGROUND/AIMS

We aimed to estimate the prevalence of cognitive impairment, and the sociodemographic and comorbid predictors of cognitive function among older, rural South African adults.

METHODS

Data were from a population-based study of 5,059 adults aged ≥40 years in rural South Africa in 2015. Cognitive impairment was defined as scoring ≤1.5 SDs below the mean composite time orientation and memory score, or requiring a proxy interview with "fair" or "poor" proxy-reported memory. Multiple linear regression estimated the sociodemographic and comorbid predictors of cognitive score, with multiplicative statistical interactions between each of age and sex with education.

RESULTS

Cognitive impairment increased with age, from 2% of those aged 40-44 (11/516) to 24% of those aged ≥75 years (214/899). The independent predictors of lower cognitive score were being older, female, unmarried, not working, having low education, low household wealth, and a history of cardiovascular conditions. Education modified the negative associations between female sex, older age, and cognitive function score.

CONCLUSIONS

The prevalence of cognitive impairment increased with age and is comparable to rates of dementia reported in other sub-Saharan African countries. Age and sex differences in cognitive function scores were minimized as education increased, potentially reflecting the power of even poor-quality education to improve cognitive reserve.

A longitudinal study of cognitive decline in rural Tanzania: rates and potentially modifiable risk factors

ABSTRACTBackground:The number of people living with dementia in sub-Saharan Africa (SSA) is expected to increase rapidly in the coming decades. However, our understanding of how best to reduce dementia risk in the population is very limited. As a first step in developing intervention strategies to manage dementia risk in this setting, we investigated rates of cognitive decline in a rural population in Tanzania and attempted to identify associated factors.

METHODS

The study was conducted in the rural Hai district of northern Tanzania. In 2014, community-dwelling people aged 65 years and over living in six villages were invited to take part in a cognitive screening program. All participants from four of the six villages were followed-up at two years and cognitive function re-tested. At baseline and follow-up, participants were assessed for functional disability, hypertension, and grip strength (as a measure of frailty). At follow-up, additional assessments of visual acuity, hearing impairment, tobacco and alcohol consumption, and clinical assessment for stroke were completed.

RESULTS

Baseline and follow-up data were available for 327 people. Fifty people had significant cognitive decline at two-year follow-up. Having no formal education, low grip strength at baseline, being female and having depression at follow-up were independently associated with cognitive decline.

CONCLUSIONS

This is one of the first studies of cognitive decline conducted in SSA. Rates of decline at two years were relatively high. Future work should focus on identification of specific modifiable risk factors for cognitive decline with a view to developing culturally appropriate interventions.

Stroke, cerebrovascular diseases and vascular cognitive impairment in Africa

With increased numbers of older people a higher burden of neurological disorders worldwide is predicted. Stroke and other cerebrovascular diseases do not necessarily present with different phenotypes in Africa but their incidence is rising in tandem with the demographic change in the population. Age remains the strongest irreversible risk factor for stroke and cognitive impairment. Modifiable factors relating to vascular disease risk, diet, lifestyle, physical activity and psychosocial status play a key role in shaping the current spate of stroke related diseases in Africa. Hypertension is the strongest modifiable risk factor for stroke but is also likely associated with co-inheritance of genetic traits among Africans. Somewhat different from high-income countries, strokes attributed to cerebral small vessel disease (SVD) are higher >30% among sub-Saharan Africans. Raised blood pressure may explain most of the incidence of SVD-related strokes but there are likely other contributing factors including dyslipidaemia and diabetes in some sectors of Africa. However, atherosclerotic and cardioembolic diseases combined also appear to be common subtypes as causes of strokes. Significant proportions of cerebrovascular diseases are ascribed to various forms of infectious disease including complications of human immunodeficiency virus. Cerebral SVD leads to several clinical manifestations including gait disturbance, autonomic dysfunction and depression. Pathological processes are characterized by arteriolosclerosis, lacunar infarcts, perivascular spaces, microinfarcts and diffuse white matter changes, which can now all be detected on neuroimaging. Except for isolated cases of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy or CADASIL, hereditary arteriopathies have so far not been reported in Africa. Prevalence estimates of vascular dementia (2-3%), delayed dementia after stroke (10-20%) and vascular cognitive impairment (30-40%) do not appear to be vastly different from those in other parts of the world. However, given the current demographic transition in both urban and rural settings these figures will likely rise. Wider application of neuroimaging modalities and implementation of stroke care in Africa will enable better estimates of SVD and other subtypes of stroke. Stroke survivors with SVD type pathology are likely to have low mortality and therefore portend increased incidence of dementia.

Identification of delirium and dementia in older medical inpatients in Tanzania: A comparison of screening and diagnostic methods

BACKGROUND

In sub-Saharan Africa, there are no validated screening tools for delirium in older adults. This study assesses clinical utility of two instruments, the IDEA cognitive screen and the Confusion Assessment Method (CAM) for identification of delirium in older adults admitted to medical wards of a tertiary referral hospital in Tanzania.

METHOD

The IDEA cognitive screen and CAM were administered to a consecutive cohort of older individuals on admission to Kilimanjaro Christian Medical Centre using a blinded protocol. Consensus diagnosis for delirium was established against DSM-5 criteria and dementia by DSM-IV criteria.

RESULTS

Of 507 admission assessments, 95 (18.7%) had DSM-5 delirium and 95 (18.7%) had DSM-IV dementia (33 (6.5%) delirium superimposed on dementia). The CAM and IDEA cognitive screen had very good diagnostic accuracy for delirium (AUROC curve 0.94 and 0.87 respectively). However, a number of participants (10.5% and 16.4% respectively) were unable to complete these screening assessments due to reduced consciousness, or other causes of reduced verbal response and were excluded from this analysis; many of whom met DSM-5 criteria for delirium. Secondary analysis suggests that selected cognitive and observational items from the CAM and IDEA cognitive screen may be as effective as the full screening tools in identifying delirium even in unresponsive patients.

CONCLUSION

Both instruments appeared useful for delirium screening in this inpatient setting, but had significant limitations. The combination of assessment items identified may form the basis of a brief, simple delirium screening tool suitable for use by non-specialist clinicians. Further development work is needed.

Adaptation and validation of the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog) in a low-literacy setting in sub-Saharan Africa

OBJECTIVE

This study aimed to assess the feasibility of a low-literacy adaptation of the Alzheimer's Disease Assessment Scale - Cognitive (ADAS-Cog) for use in rural sub-Saharan Africa (SSA) for interventional studies in dementia. No such adaptations currently exist.

METHODS

Tanzanian and Nigerian health professionals adapted the ADAS-Cog by consensus. Validation took place in a cross-sectional sample of 34 rural-dwelling older adults with mild/moderate dementia alongside 32 non-demented controls in Tanzania. Participants were oversampled for lower educational level. Inter-rater reliability was conducted by two trained raters in 22 older adults (13 with dementia) from the same population. Assessors were blind to diagnostic group.

RESULTS

Median ADAS-Cog scores were 28.75 (interquartile range (IQR), 22.96-35.54) in mild/moderate dementia and 12.75 (IQR 9.08-16.16) in controls. The area under the receiver operating characteristic curve (AUC) was 0.973 (95% confidence interval (CI) 0.936-1.00) for dementia. Internal consistency was high (Cronbach's α 0.884) and inter-rater reliability was excellent (intra-class correlation coefficient 0.905, 95% CI 0.804-0.964).

CONCLUSION

The low-literacy adaptation of the ADAS-Cog had good psychometric properties in this setting. Further evaluation in similar settings is required.

Cognitive stimulation therapy as a sustainable intervention for dementia in sub-Saharan Africa: feasibility and clinical efficacy using a stepped-wedge design

BACKGROUND

Cognitive stimulation therapy (CST) is a psychosocial group-based intervention for dementia shown to improve cognition and quality of life with a similar efficacy to cholinesterase inhibitors. Since CST can be delivered by non-specialist healthcare workers, it has potential for use in low-resource environments, such as sub-Saharan Africa (SSA). We aimed to assess the feasibility and clinical effectiveness of CST in rural Tanzania using a stepped-wedge design.

METHODS

Participants and their carers were recruited through a community dementia screening program. Inclusion criteria were DSM-IV diagnosis of dementia of mild/moderate severity following detailed assessment. No participant had a previous diagnosis of dementia and none were taking a cholinesterase inhibitor. Primary outcomes related to the feasibility of conducting CST in this setting. Key clinical outcomes were changes in quality of life and cognition. The assessing team was blind to treatment group membership.

RESULTS

Thirty four participants with mild/moderate dementia were allocated to four CST groups. Attendance rates were high (85%) and we were able to complete all 14 sessions for each group within the seven week timeframe. Substantial improvements in cognition, anxiety, and behavioral symptoms were noted following CST, with smaller improvements in quality of life measures. The number needed to treat was two for a four-point cognitive (adapted Alzheimer's Disease Assessment Scale-Cognitive) improvement.

CONCLUSIONS

This intervention has the potential to be low-cost, sustainable, and adaptable to other settings across SSA, particularly if it can be delivered by non-specialist health workers.

Mild Cognitive Impairment in Rural Tanzania: Prevalence, Profile, and Outcomes at 4-Year Follow-up

OBJECTIVE

Mild cognitive impairment (MCI) is recognized as a high-risk condition for conversion to dementia, although data on outcomes of MCI in sub-Saharan Africa are scarce. We investigated outcomes of MCI over a 4-year period in Tanzania and considered risk factors for conversion to dementia.

METHODS

In a longitudinal cohort study in the Hai district, Tanzania, patients with MCI were identified during a two-phase prevalence study carried out in 2010. Of 1,198 people aged 70 years and over screened in phase I, a stratified sample of 296 were fully assessed in phase II. MCI was defined according to international consensus criteria. DSM-IV criteria were used for dementia diagnosis. Background demographic and risk factor data were collected, and neuropsychiatric symptoms were assessed using the neuropsychiatric inventory. Patients were followed-up in 2011, 2012 and 2014.

RESULTS

Forty-six MCI patients were identified. After adjusting for stratification, the crude prevalence of MCI was 7.0% (95% CI: 3.6-10.4). Over a 4-year period, 15 patients (32.6%) progressed to dementia, 2 patients (4.3%) returned to normal cognition, 1 developed late-onset schizophrenia, 8 patients (17.4%) had stable MCI, 19 patients (41.3%) died, and 1 refused assessment. Age, sex, education levels, body mass index, hypertension, and comorbidity were not associated with progression to dementia.

CONCLUSION

In this rural Tanzanian population, rates of conversion from MCI to DSM-IV dementia were similar to those reported in high-income countries. Over a third of all patients had died at the 4-year follow-up.

The prevalence and burden of behavioural and psychological symptoms of dementia in rural Tanzania

OBJECTIVES

Behavioural and psychological symptoms (BPS) in dementia are common in high-income countries, but there are few data from sub-Saharan Africa. Our aim was to estimate the prevalence and pattern of BPS and associated caregiver distress in rural Tanzania.

METHODS

Prevalent cases of dementia (aged 70 and over) were identified during a community-based door-to-door study in six rural villages in Tanzania. Following cognitive screening, a stratified sample (over-sampled for people with dementia) of cases underwent a detailed clinical assessment including the brief 12 item neuropsychiatric inventory (NPI-Q), which assesses BPS and associated caregiver distress over the preceding 30 days.

RESULTS

Of 78 people with dementia, at least one current BPS was reported by 69 (88.4%), with 40 (51.3%) reporting 3 or more symptoms. In 172 people with no cognitive impairment, 110 (64.0%) reported at least one symptom and 48 (27.9%) reported 3 or more. In dementia cases, the most frequent symptoms reported were anxiety (47.4%), agitation/aggression (38.5%), night-time behavioural disturbance (34.6%), irritability (33.3%) and depression (33.3%).

CONCLUSION

The frequency of BPS in dementia in this rural Tanzanian population is high and comparable to that reported in prevalence studies from high income countries. Symptoms were also common, although to a lesser degree, amongst cognitively intact subjects. BPS are likely to have a significant impact on quality of life for elderly persons and their carers in low-income settings. Low-cost interventions, such as community-based therapy and education, are needed.

Levels of functional disability in elderly people in Tanzania with dementia, stroke and Parkinson's disease

BACKGROUND

Disability is associated with increasing age and poverty, yet there are few reliable data regarding disability amongst the elderly in low-income countries. The aim of this study was to compare disability levels for three of the most common neurological, non-communicable diseases: dementia, stroke and Parkinson's disease (PD).

METHODS

We performed a community-based study of people aged 70 years and over in 12 randomly selected villages in the rural Hai district of Tanzania. Participants underwent disability assessment using the Barthel Index, and clinical assessment for dementia, stroke and PD.

RESULTS

In a representative cohort of 2232 people aged 70 years and over, there were 54 cases of stroke, 12 cases of PD and estimated (by extrapolation from a sub-sample of 1198 people) to be 112 cases of dementia. People with stroke were the most disabled, with 62.9% having moderate or severe disability. Levels of moderate or severe disability were 41.2% in people with dementia and 50.0% in people with PD. However, the higher prevalence of dementia meant that, at a population level, it was associated with similar levels of disability as stroke, with 18.5% of 249 people identified as having moderate or severe disability having dementia, compared to 13.7% for stroke and 2.4% for PD.

CONCLUSIONS

Levels of disability from these conditions is high and is likely to increase with demographic ageing. Innovative, community-based strategies to reduce disability levels should be investigated.

Mortality rates in community-dwelling Tanzanians with dementia and mild cognitive impairment: a 4-year follow-up study

BACKGROUND

we have previously conducted a community-based prevalence study of dementia in older adults living in the rural Hai district of Tanzania. The aim of this study was to record mortality rates at 4 years post-diagnosis, of those with dementia, mild cognitive impairment (MCI) and no cognitive impairment.

METHODS

during Phase I of the prevalence study, 1,198 people aged 70 years and over were screened, and a stratified sample of 296 was assessed for the presence of dementia or MCI in Phase II. Seventy-eight people had dementia and 46 had MCI. Four years after diagnosis, we attempted to follow-up all those seen in Phase II and record all deaths.

RESULTS

of the 296, follow-up data were available for 287 (97.0%), including 77 with dementia and 45 with MCI. Of the 172 with no cognitive impairment, 165 (95.9%) were followed up and a sample of 89 people selected as representative of the background population. Forty-eight people with dementia (62.3%), 19 with MCI (42.2%) and 11 with no cognitive impairment (12.4%) had died at 4-year follow-up. After adjusting for the effects of age, gender and education, the hazard ratio was 6.33 (95% CI 3.19-12.58) for dementia and 3.57 (95% CI 1.64-7.79) for MCI relative to people with no cognitive impairment. Mortality rates were highest in those with vascular dementia.

CONCLUSION

dementia and MCI were associated with excess mortality relative to those with no cognitive impairment.