Table 1:
Summary of community-based epidemiological studies of dementia in Africa
| Author/Site, Country | Year | Criteria | Sample (n) | Age (yrs) | Prevalence | Identified Risk Factors | Limitations | ||
|---|---|---|---|---|---|---|---|---|---|
| Dementia | AD | VaD | |||||||
| West Africa | |||||||||
| Hendrie et al22/ Ibadan, Nigeria | 1995 | DSM III-R ICD 10 |
2494 | ≥ 65 | 2.3% | - | No consideration for educational status. Cultural bias in diagnosis. High rate in Indianapolis cohort. Age was determined using historical landmarks. | ||
| Ogunniyi et al16/Ibadan, Nigeria | 1997 | DSM III-R ICD 10 |
2494 | ≥ 65 | 64.3% | 28.6% | - | Age wasdetermined using historical landmarks. High illiteracy rates. No radiological confirmation | |
| Hall et al63/Ibadan, Nigeria | 2006 | DSM III-R ICD 10 |
1075 | ≥ 70 | Dyslipidemia. | Small number of AD cases. Survivor bias as most of the attrition from earlier cohort were due to mortality. Criteria for control group uncertain. Cross-sectional design not appropriate to determine association | |||
| Ochayi and Thatcher78/Jos, Nigeria | 2006 | CSID | 280 | ≥ 65 | 6.4% | Age, Female sex, BMI, NSAIDs | Possible over-estimation of dementia rate due to one stage process used. Wide confidence intervals for estimates. Estimated ages. Cross-sectional design. | ||
| Gureje et al20/Southwest, Nigeria | 2006 | 10-WDRT DSM IV |
2152 | ≥ 65 | 10.1 % | Age, Female sex, Lifetime history of alcohol use | Cross-sectional design. Incomplete information about disabilities. | ||
| Guerchet et al24 /Djidja, Benin | 2009 | DSM-IV | 514 | ≥ 65 | 2.6% | 53.8% | 7.7% | Age | Self-reported education. Informal age confirmation. Cross-sectional design. Low proportion of subject schooled. No radiological confirmation |
| Yusuf et al26/Zaria, Nigeria | 2011 | DSM IV ICD 10 |
322 | ≥ 65 | 2.8% | 66.7% | 33.3% | Age | One stage selection. No radiological confirmation |
| Paraiso et al25/Cotonou, Benin | 2011 | DSM-IV | 1162 | ≥ 65 | 3.7% | Age, Female sex | Sub-section of CSI-D used. Neuropsychology test do not have adjusted normative values for illiterate population. Relatives not involved to confirm details | ||
| Gureje et al37/Southwest, Nigeria | 2011 | 10-WDRT CHIF |
1225 | ≥ 65 | Age, Gender, Poor economic status, Rural Living, Social Isolation | Preponderance of persons with little or no education. Use of 10-WDRT | |||
| Akinyemi et al41/ Ibadan and Abeokuta, Nigeria | 2014 | DSM-IV ASA/AHA |
143 (Stroke survivors) | ≥.45 | 8.4% | Age, Low Education, Medial temporal lobe atrophy, Pre-stroke cognition | Modest sample size. Incomplete neuroimaging. | ||
| Ogunniyi et al42/Lalupon, Nigeria | 2016 | DSM-IV | 613 | ≥ 65 | 2.9% | 58.8% | 11.7% | Age | Lack of neuroimaging. Identification of treatable conditions |
| Ojagbemi et al35/Southwest, Nigeria | 2016 | 10-WDRT CHIF |
2149 | ≥ 65 | Age, Gender, Socioeconomic status, Pre-existing cognitive decline, Occupational complexity. | Inaccurate survival data. Attrition. Small size of dementia mortality sample | |||
| Sarfo et al40/Kumasi, Ghana | 2017 | DSM-IV | 147 (Stroke survivors) | Age, Education, Functional ability | Modest sample size. Cross-sectional study. Neuroimaging not available for review. Lack of pre-stroke cognitive status. | ||||
| Adoukonou et al/ Parakou, Benin | 2020 | DSM-IV-TR | 440 | ≥ 50 | 3.2% | 64.3% | 21.4% | Age, Living alone, Low vegetable intake | Not generalizable. Verbal report of vascular factors. Participants may have benefitted from having a better socioeconomic status and better access to health care than the overall older population. Sample size was small. High level of refusals. Use of the brief version of the CSI-D also carries some limitations. |
| Central Africa | |||||||||
| Guerchet et al27/ Bangui, CAR | 2010 | DSM-IV | 496 | ≥ 65 | 8.1% | 82.5% | 17.5% | DSM-IV underestimate. No radiological confirmation | |
| Guerchet et al27 / Brazzaville, Congo | 2010 | DSM-IV | 520 | ≥ 65 | 6.7% | 68.6% | 31.4% | ||
| Guerchet et al65/ Bangui CAR and Brazzaville, Congo | 2012 | DSM-IV | 977 | ≥ 65 | 7.6 % | Age, Female sex, Hypertension, Peripheral artery disease, Low BMI, Depression, Lack of education | High rate of missing data. Cross-sectional design. Absence of APOE genotyping. No radiological confirmation | ||
| East Africa | |||||||||
| Longdon et al29/Kilimanjaro, Tanzania Paddick et al63/Kilimanjaro, Tanzania |
2013 2014 |
DSM-IV | 1198 | ≥ 70 | 6.4% | 48.7% | 41.0% | Diabetes | No radiological confirmation. Incomplete radiological and laboratory investigations. Too little number for subtypes. Attrition. Non-medically trained census enumerators. |
| Mubangizi et al30/Rural Southwest, Uganda | 2020 | Brief CSID | 400 | ≥ 60 | 20.0% | Age. But having some education, exercise and ventilated kitchen were protective | No structured clinical interviews. Brief CSID used. Early and midlife exposure variables were measured by self-reporting. | ||
| Yoseph et al162/Kilimanjaro, Tanzania | 2021 | DSM- V | 3011 | ≥ 70 | 8.9% | - | |||
| South Africa | |||||||||
| Ramlall et al/Nursing Homes, South Africa | 2013 | DSM-IV-TR | 140 | ≥ 60 | 7.9% | 40.0% | Blackouts, Hypertension, Exercise, Visual and Hearing impairment. | Poor sampling – small size, low number of black participants, low number of dementia cases. Inter-rater reliability not quantified. | |
| De Jager et al13/ Amatole District, South Africa | 2017 | CSID | 1394 | ≥ 65 | 11.0% | Older age, dépressive symptoms | No clinician resources to provide a DSM-IV diagnosis of dementia. Targeted sample size not achieved. Sampling involved only low-income rural community | ||
| North Africa | |||||||||
| Farrag et al34/ Assiut Governorate, Egypt | 1998 | DSM-III R | 2000 | ≥ 60 | 4.5% | 53.0% | 22.9% | - | NS |
| El Tallawy et al23/ Al Kharga District, Egypt | 2012 | DSM-IV-TR | 8173 | ≥ 50 | 2.3% | 51.2% | 28.7% | - | NS |
| El Tallawy et al32/ Al-Quseir city, Egypt | 2014 | DSM-IV | 4329 | ≥ 50 | 3.8% | 48.3% | 36.8% | - | NS |
| Khedr et al33/ Qena Governorate, Egypt | 2015 | DSM-IV | 619 | ≥ 60 | 5.1% | 34.3% | 25.7% | - | NS |
Abbreviations: DSM- IIIR – Diagnostic & Statistical Manual of Mental Disorders–3rd Edition Revised; ICD- 10 – International Classification of Diseases 10th Revision; WDRT - 10-Word Delayed Recall Test; CHIF - Clinician Home-based Interview; DSM – IV - Diagnostic & Statistical Manual of Mental Disorders– 4th Edition; DSM – IV-TR- Diagnostic & Statistical Manual of Mental Disorders– 4th Edition Text Revision; CSID – Community Screening Instrument for Dementia; CAR – Central Africa Republic; NS - not stated