Dementia is one of the leading causes of disability and mortality in older adults (Alzheimer’s Disease International [ADI] 2015). According to Nichols et al. (2022), more than 60% of people with dementia live in low-middle-income countries (LMICs), with the highest estimates in Asia and Africa (ADI 2015; Nichols et al. 2022). In Africa, the regional forecast of dementia prevalence in people ≥ 60 years ranges from 5.1% in North Africa to 20.0% in sub-Saharan Africa (SSA) (Akinyemi et al. 2022). In South Africa, dementia is reported to be between 6.3% and 12.5% (De Jager et al. 2017; Farina et al. 2023; Ramlall et al. 2013; Vanderpoel, Heyns & 10/66 Dementia Research Group 2012). The prevalence of dementia in LMICs, such as in South Africa, has been predicted to increase, and the increase is associated with low interventions aimed at risk reduction in these countries (ADI 2015; Nichols et al. 2022).

A combination of non-modifiable factors, such as age and gender, and modifiable factors, such as depression, hypertension, education, and socioeconomic levels, are associated with dementia (ADI 2017; George-Carey et al. 2012; Mavrodaris, Powell & Thorogood 2013; Olanyika & Mbuyi 2014; Paddick et al. 2014). In Africa, increasing age continues to be a significant risk factor, with the highest rate of dementia expected from the 70–80+ age group (ADI 2017; George-Carey et al. 2012; Gorelick et al. 2011; Mavrodaris et al. 2013; Olanyika & Mbuyi 2014). In addition, women are considered more at risk than men (ADI 2017; De Jager et al. 2017; Yusuf et al. 2018), because women have a higher life expectancy and increased neurobiological vulnerability during the postmenopausal period (Podcasy et al. 2016). Another risk factor, mainly in LMICs, is related to regional settings. For example, people in urban areas seem less vulnerable to dementia than those in rural areas (De Jager et al. 2015; Gureje et al. 2011). This is because commonly rural populations are older and because of poor access to health, they have higher rates of poorly managed chronic conditions, such as hypertension, diabetes, hyperlipidaemia, and depression compared to urban populations (Olivier, Cacabelos & Naidoo 2018; Rahman et al. 2020). The combination of these risk factors make rural communities disproportionately vulnerable to dementia.

There is a paucity of dementia prevalence and risk studies in Southern Africa; therefore, a need was identified for epidemiological studies in South Africa (De Jager et al. 2015). The authors identified two community-based studies estimating dementia prevalence in South Africa (De Jager et al. 2017; Ramlall et al. 2013; Vanderpoel et al. 2012). The two studies varied in methods used and were in different provinces. One study was conducted in KwaZulu-Natal (KZN) nursing homes, but there were no community studies (Ramlall et al. 2013). Therefore, the authors conducted a community study in one of the 11 districts of KZN province. This study estimated the prevalence of dementia and measured the sociodemographic and clinical risks in older adults in low socioeconomic communities in the iLembe district. It is important to measure dementia prevalence and identify risk factors in people with dementia to develop reduction strategies and improve the longevity of older adults.

A total of 320 participants were recruited. Of these, some participants were from KwaDukuza (86; 26.9%), KwaMaphumulo (40; 12.5%), eMandeni (128; 40%) and eNdwedwe (66; 20.6%). Most participants were black African (225; 70.3%) and isiZulu speakers (220; 68.8%). The mean age of the participants (N = 320) was 69.43 (standard deviation [SD] = 7.76), with a minimum age of 60 years and maximum age of 94 years (Table 1).

This study investigated the prevalence and correlates of dementia in older adults in a community setting. The prevalence of dementia was 13.4%. This prevalence rate is a little higher compared to other community studies in South Africa, which reported a prevalence of 6.3% – 12.5% in older adults living in rural and urban settings (Farina et al. 2023; Vanderpoel et al. 2012). It is also a little higher when compared to other studies from other African and Western countries (ADI 2015; Guerchet et al. 2009, 2010, 2014; Gureje et al. 2011; Paraïso et al. 2011; Ogunniyi et al. 2016; Longdon et al. 2012; Yusuf et al. 2011). The different life expectancy rates and differences in research methods are some of the factors that might contribute to variable prevalent rates in some of the studies when compared to this study. With increasing life expectancy in LMICs, it is expected that dementia prevalence will increase (Nichols et al. 2022). Hence, it is anticipated that dementia in South Africa might also increase. However, as seen in the dementia trends in high-income countries (Nichols et al. 2022), dementia increase in LMICs can also be lowered if priority is placed on reducing modifiable risk factors.

Risk factors associated with dementia in this study included ageing, depression, not having a partner and education. Low education, depression and loneliness have also been identified in other African studies (George-Carey et al. 2012; Mavrodaris et al. 2013; Olanyika & Mbuyi 2014; Paddick et al. 2014; Yusuf et al. 2018), confirming the prominent plight of these factors in older African populations. Not having a partner in this study increased the risk of dementia by seven-fold for those who are single and three-fold for those who are widowed. This speaks to issues of loneliness and isolation in older adults. Other factors associated with loneliness and isolation in older adults include living alone, losing family or friends, chronic illness, and hearing loss (National Academies of Sciences, Engineering, and Medicine 2020). These results suggest that it is important that older people are included in community activities to combat loneliness and isolation.

Ageing is a primary risk factor for dementia (ADI 2015; De Jager et al. 2017; Longdon et al. 2012), doubling the risk of dementia in those aged < 80 years in this study compared to those aged 60 years – 69 years. Alzheimer’s Disease International (2015) reported that a person’s risk increases as they age, doubling every 5 years. In addition, older people are more likely to live with other comorbid illnesses such as hypertension, stroke, diabetes, and hypercholesterolaemia, also associated with dementia (Guo et al. 2018; Huang et al. 2015), thereby increasing the vulnerability of an older person to developing dementia.

Identifying and reducing risks, such as increasing the quality and levels of education and improving the control of depression and cardiovascular diseases, can effectively lower the incidence of dementia (ADI 2015; Nichols et al. 2022; WHO 2017). Quality education and cognitive stimulation programmes must be prioritised in developing countries to build and enhance cognitive reserve from a younger age. Further, public health interventions should be prioritised at a grassroots level to educate people about dementia risk factors such as cardiovascular risks. Addressing risk factors through public health interventions is a pathway to reducing dementia prevalence and altering the trajectory of age-specific prevalence. Lastly, the treatment gap between people diagnosed with dementia and those undiagnosed but with dementia must be reduced. This means that public health screenings for dementia should be encouraged. Older people should be screened at community clinics when they routinely visit to collect medications. To achieve this, primary healthcare staff can easily administer assessment tests that are readily available, easy to administer, and not time-consuming. There is a greater need for using validated and simple neuropsychological tools for early diagnosis of cognitive impairment (Ramlall et al. 2013). These tests must be easily incorporated into the routine screening of older people in primary healthcare settings in conjunction with the DSM-5 and/or the ICD-11. Cases of dementia can be identified, and routine care commenced, including laboratory testing and symptomatic management.

This study’s primary objective was to measure the risk factors and prevalence of dementia in the iLembe district. Dementia prevalence was 13.4%. Many people with dementia in South African communities likely remain undiagnosed, and do not have access to treatment, care and support that a formal diagnosis can provide. More longitudinal studies need to be done to ascertain the actual trajectory of dementia in South Africa. The identified risk factors for dementia were age, low levels of education, lack of a spouse and a history of depression. The early identification of cognitive impairment is important in devising possible interventions that can help to reduce the burden on those affected and impacted by dementia and to lighten the socioeconomic burden of the disease on the country’s resources (Schutte et al. 2021).

Future research in South Africa needs to be more representative and include longitudinal studies. In addition, future research needs to focus on exploring and eliminating the modifiable risk factors mentioned for populations identified as being at risk, especially those in rural areas and low-income households. It is recommended that when tests such as the MMSE are used to screen for dementia, they are used with caution and in combination with other tests. This study used a combination of tests and only counted participants as having dementia if the combined test results corresponded with the Diagnostic and Statistical Manual of Mental Disorders (DSM) 5 and ICD 11 criteria for dementia instead of relying on the results of the individual psychometric tests. Combining the MMSE, AD8 and IADL provides better diagnostic accuracy in the absence of laboratory tests, and can be easily incorporated into routine care by primary healthcare providers for diagnosing dementia.

Limitations of this study include the cross-sectional design, which lessened the ability to establish causal-effect relationships between dementia and the independent variables. In addition, this study did not include laboratory testing. However, other studies have predicted dementia without laboratory testing, and those screened as positive for dementia were referred for further testing at their healthcare institutions. This study was conducted in one district and was not a national study. Therefore, results should be generalised with caution to other communities in South Africa. Notwithstanding these limitations, the study provides insight relevant to issues related to dementia prevalence in South Africa and other developing countries.