Epidemiology of Dementia among the Elderly in Sub-Saharan Africa

Table 2

Epidemiologic research on dementia in sub-Saharan Africa—hospital-based studies.

Country	Authors	Study design/methodology	Prevalence rate	Incidence rate	Risk factors/associated conditions
Nigeria	Ogunniyi et al., 1993 [41]	(i) Cross-sectional hospital-based study conducted in Nigeria (Ibadan); (ii) Age ≥ 47 years; (iii) = 57,440; 37 cases had dementing illnesses; (iv) Diagnostic tools: ICD-10R, NINCDS-ADRDA, and Hachinski ischemic score	(i) 37 out of 57,440 (0.064%) hospitalized patients had dementing illnesses; (ii) Eighteen cases out of 37 (48.65%) had vascular dementia; (iii) Probable primary degenerative dementia accounted for only one case; it was therefore postulated that it is rare in Nigeria		Hypertension, parkinsonism, diabetes, and benign prostatic hyperplasia were associated with dementia
	Osuntokun et al., 1995a [42]	(i) Autopsy survey of brains; (ii) Age ≥ 40 years; (iii) = 198 brains of Nigerians including 45 brains of people of age ≥ 65 years			Histological markers of AD (cortical neuronal loss, amyloid beta plaques, neurofibrillary tangles, and amyloid angiopathy) are minimum or absent
	Baiyewu et al., 1997 [43]	(i) Cross-sectional survey of 2 nursing homes in Lagos; (ii) Age: elderly—age range not disclosed; (iii) = 23; (iv) Psychiatric disorders diagnosis: DSM-III-R and AGECAT	(i) Dementia prevalence was 47.83% (11 out of 23 patients); (ii) Prevalence of psychiatric disorders is similar to that found in similar institutions in industrialized countries
	Ekenze et al., 2010 [44]	(i) Cross-sectional survey (2003–2007) of neurological admissions at a university hospital in South East Nigeria; (ii) = 1249; 51% male, 49% female	Prevalence of dementia was 3% of all neurological diagnoses
	Amoo et al., 2011 [45]	(i) Cross-sectional survey; (ii) Review of hospital records of patients with diagnoses of dementia or dementing illness at a neuropsychiatric practice in South-Western Nigeria (1998–2007); (iii) = 240, 294; (iv) Diagnostic tools: ICD-10 criteria as	(i) Prevalence of probable dementia was 0.045%; (ii) AD and VaD were the predominant subtypes, accounting for; 57.41% and 18 16.67% of cases, respectively
Ghana	Turkson and Asamoah, 1997 [46]	(i) Retrospective study at a psychiatric outpatient clinic in the city of Accra; (ii) Age ≥ 60 years; (iii) = 35; (iv) Diagnostic tool: ICD-10	Dementia is the second most common psychiatric disorder among 35 patients who attended a psychiatric outpatient clinic in Accra, Ghana
Kenya and Tanzania (East Africa)	Kalaria et al., 1997 [47]	(i) Autopsy surveys of brain tissue; (ii) Histology of brains of east Africans to search for typical lesions of AD (Amyloid beta deposits and neurofibrillary tangles)			(i) Reported high frequency of APOE-ε4 in elderly east Africans without dementia; (ii) Study suggests that APOE-ε4 is a nonspecific factor for dementia in east Africans
	Winkler et al., 2011 [48]	(i) Prospective analysis carried out over 8 months at a hospital in northern Tanzania; (ii) = 768; (iii) Subjects had neurological/psychiatric diagnoses; (iv) Diagnostic tool: Glasgow Coma Scale	(i) Dementia was the cause of acute confusion in 6.9% of cases; (ii) In 0.2% cases, dementia was the cause of impaired consciousness
Senegal	Touré et al., 2008 [49, 50]	(i) Cross-sectional survey conducted from 2004-2005; (ii) Age ≥ 55 years; (iii) = 872; (iv) Phase 1: questionnaire; (v) Phase 2: clinical exam and neuropsychiatric evaluation	Prevalence of dementia is 6.6% at a university medical center in the city of Dakar
	Touré et al., 2012 [51]	(i) Cross-sectional survey; (ii) Age ≥ 65 years; (iii) = 507, urban area; (iv) Screening tool: “the test of Senegal”; (v) Dementia diagnosis: DSM-IV-R	Prevalence of dementia estimated at 8.87% at a geriatric health center in city of Dakar		Age, illiteracy, and low social network linked to high risk of dementia in elderly as in Western countries
Burkina Faso	Napon et al., 2009 [52]	(i) Cross-sectional survey (2005 to 2007); (ii) Age ≥ 15 years; (iii) = 15, 815; (iv) Dementia diagnosis: DSM-IV	(i) Prevalence of dementia in patients who visited the hospital and consulted in the various services in this university hospital was 0.46%; (ii) Prevalence of dementia in hospitalized patients was 2.21%; (iii) AD was the most prevalent type; (iv) Average age of patients diagnosed with dementia was 62.20 years
South Africa	Kalula et al., 2010 [53]	(i) Cross-sectional survey (2003–2008); (ii) = 305; (iii) University of Cape Town Memory Clinic; (iv) Age: 37–89; (v) Mean age: 70	Dementia made up 74% of all diagnoses at a memory clinic
	Ramlall et al., 2013 [54]	(i) Cross-sectional survey; (ii) Conducted in group residential homes for the elderly; (iii) Age ≥ 60 years; (iv) = 140; (v) 97 females, 43 males; (vi) 106 participants had less than 12 years education; (vii) Diagnosis of dementia based on DSM-IV-TR	(i) Dementia prevalence was 7.9%; (ii) Prevalence of MCI was 37.1%		(i) Increasing age associated with MCI and dementia; (ii) No association between gender and cognitive impairment; (iii) MCI associated with lower education level; (iv) Prevalence of vascular risk factors ranged from 66.4% (hypertension) to 14.3% (stroke); (v) Subjective memory complaints were significantly associated with cognitive impairment
Cameroon	Tegueu, et al., 2013 [55]	(i) Retrospective chart review over 6-year period; (ii) Age ≥ median of 45 years; (iii) = 4526; (iv) Urban outpatient clinic; (v) Diagnostic tool: ICD-10	(i) Prevalence of dementia was 2.85% at %) at an urban clinic with neurological consultation service; (ii) Dementia was the tenth leading neurologic disease

AA: African Americans; AGECATL: automated geriatric examination for computer-assisted taxonomy; CERAD: the consortium to establish a registry for Alzheimer’s disease; CSID: community screening instrument for dementia; DSM-III-R: diagnostic and statistical manual of mental disorders 3rd edition revised; DSM-IV: diagnostic and statistical manual of mental disorders 4th edition; ICD-10: international classification of diseases 10th revision; GMS: the geriatric mental status schedule; MMSE: minimental state examination; SDT: stick design test; NSAID: nonsteroidal anti-inflammatory drugs; NINCDS-AIREN: National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences; NINCDS-ADRDA: National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association.