Dementia Prevalence in a Rural Region of South Africa: A Cross-Sectional Community Study

Abstract

Background:Dementia is a growing concern for low- and middle-income countries where longevity is increasing and service provision is poor. Global prevalence estimates vary from 2% to 8.5% for those aged 60 years and older. There have been few dementia studies in sub-Saharan Africa, and prevalence data are lacking for South Africa.Objective:To conduct a large dementia prevalence study in a low income rural population in South Africa.Methods:1,394 Xhosa-speaking community dwellers, aged ≥60 y (mean age±sd 71.3±8.3 y), in three clinic catchment areas, were screened at home. Trained community health workers administered the brief Community Screening Instrument for Dementia (CSID) to participants and informants to assess cognitive and functional capacity. Depressive symptoms were assessed with three questions from the EURO-D.Results:The prevalence estimate using published CSID sensitivity/specificity values was 0.8 (95% CI: 0.06–0.09). Using CSID cut-off scores the estimated prevalence was 0.12 (95% CI: 0.10–0.13), with 161 screen-positives. Both methods gave a rate of 0.11 (95% CI: 0.09–0.13) for those over 65 years (n = 1051). 68.6% of participants were female and 69.8% had less than 7 years of education. Dementia risk was associated with older age and symptoms of depression, but not with sex. The association with education was not significant when controlled for by age.Conclusions:Dementia prevalence estimates were higher than expected for this low-income rural community. There is a need for increased dementia awareness and feasible support interventions. We also need further studies of regional prevalences, dementia subtypes, and modifiable risk factors in South Africa.

Prevalence and correlates of Alzheimer’s disease and related dementias in rural Uganda: cross-sectional, population-based study

“…In this population-based study of 400 older-age adults from rural Uganda, we estimated the population prevalence of dementia to be 20%. This estimated prevalence is higher than the 8% estimated prevalence rate reported in a recently published community-based survey from South Africa, which had a similar age distribution of study participants and used a similar screening instrument (i.e., the brief CSID) [9]. Notably, in our study, nearly 80% of positive dementia screens were categorized as such due to the informant/caregiver score, which exceeds the 30% reported by de Jager et al [9].…”

“…This estimated prevalence is higher than the 8% estimated prevalence rate reported in a recently published community-based survey from South Africa, which had a similar age distribution of study participants and used a similar screening instrument (i.e., the brief CSID) [9]. Notably, in our study, nearly 80% of positive dementia screens were categorized as such due to the informant/caregiver score, which exceeds the 30% reported by de Jager et al [9]. The difference in prevalence rates between our study and de Jager's study is therefore due to differences in the distribution of informant scores.…”

“…In most settings, the screening prevalence of dementia likely exceeds the true prevalence of dementia, due to the nonzero false positive rate. While the true prevalence of dementia is unknowable in the absence of data from a criterion standard (i.e., clinical diagnosis made on the basis of a structured clinical interview), we followed the "back estimation" method described by de Jager et al [9] to estimate the prevalence of dementia based on our screening data and the known sensitivity (0.95) and specificity (0.90) of the brief CSID [8]. First, we estimated the number of true positives (TP) given the well-known relationships between sensitivity (SE)/ specificity (SP) and the number of test positives (testp) and test negatives (testn):…”

Contemporary views on dementia as witchcraft in sub‐Saharan Africa: A systematic literature review

“…The prevalence of dementia in sub-Saharan Africa ranges from 2.3%-21.6%, (Olayinka & Mbuyi, 2014). Previously, the prevalence of dementia in sub-Saharan Africa was estimated to be lower than Western countries, but recent data suggest the prevalence is in fact parallel (Longdon et al, 2013), if not higher (de Jager, Msemburib, Pepperc, & Combrincka, 2017). However, there is a paucity of research exploring the prevalence and incidence of dementia in Africa, and the need for epidemiological studies remains (de Jager et al, 2017;Olayinka & Mbuyi, 2014).…”

“…Previously, the prevalence of dementia in sub-Saharan Africa was estimated to be lower than Western countries, but recent data suggest the prevalence is in fact parallel (Longdon et al, 2013), if not higher (de Jager, Msemburib, Pepperc, & Combrincka, 2017). However, there is a paucity of research exploring the prevalence and incidence of dementia in Africa, and the need for epidemiological studies remains (de Jager et al, 2017;Olayinka & Mbuyi, 2014). An element that may be more relevant in African countries is the prevalence of HIV-associated dementia (HAD), as the prevalence of HAD ranges from 15%-30% in populations where the disease has gone untreated (Grant, 2008).…”