Table 4.

Overview of studies on amyotrophic lateral sclerosis risk factors in sub-Sahara Africa

Author, year of publication	Country/setting	Design/year	Population characteristics	Diagnostic criteria/tools	Prevalence	Risk factors	Comments
Wall [130],1972	Zimbabwe	Retrospective	13 (men 10) consecutive patients; age 24–55 y.	Clinical (no ENMG)	NA	NA	6 participants had sensory changes
	Hospital-based	1967-1971
Osuntokun [126], 1974	Nigeria	Retrospective	92 patients with MND ALS 73; PMA 10, SMA 9	ENMG/Muscle biopsy/	21/100,000	NA	Mean age at onset: 39 y
							Mean duration of disease exceeded 15 y in 8% of participants
	Hospital-based	1958 -1973
							4 patients with ALS had poliomyelitis in childhood.
Osuntokun [19], 1987	Nigeria	Cross-sectional	18954 participants (men 9282); 58% <20 y and 11% > 50 y	Screening questionnaire developed by the authors	MND: 15/100,000	NA
	Community-based	1985
Cosnett [125], 1989	South Africa Hospital-based	Retrospective Cases collected during 9.5 y.	59 blacks (mean age 47.4 y.); 16 whites and 2 coloured (mean age 54 y.) 9 Indians (mean age 54 y)	Clinical and ENMG in 45%	Blacks/white & coloured/Indians (per 100,000) 0.88/2 · 7/1.4	NA	Mean age of onset: 47 y (blacks) and 54 y (in whites and Indians)
							29% of participants not followed up.
Ekenze [21], 2010	Nigeria	Retrospective	8440 admissions; 1249 (men 640) with neurological diseases, mean age 45 y.; 10 (men 4) with ALS	Not specified	800/100,000	NA
	Hospital-based	2003-2007
Abdulla [127], 1997	Sudan	Retrospective:	28 (men 17) patients with MND; 19 (men 14) with ALS	Clinical and ENMG	NA	Family history of MND in 14%	Mean age of onset: 40 y
	Hospital-based	1993-1995
Kengne [16], 2006	Cameroon	Retrospective	4041 neurologic consultations; 145 with neurodegenerative diseases 10 (men 8) with ALS; mean age 50.9 y.	Not provided	12% of all neurodegeneration 250/100,000 of all neurologic consultation		4 selected degenerative brain diseases: Dementia, PD, ALS and chorea
	Hospital-based	1993-2001
Imam [131], 2004	Nigeria	Retrospective	16 (men 15) participants; age 16-60 y.	El Escorial diagnostic criteria for ALS, no ENMG	NA	NA
	Hospital-based	1980-99
Adam [129], 1992	Kenya	Retrospective	47(men 35) participants with MND;	Clinical (ENMG in 1/3 of participants)	NA	NA	Duration of disease: 5 m to 4 y.
	Hospital-based	1978-88	Age 13-80 y
			18 had ALS
Tekle-Haimanot [122], 1990	Ethiopia	Cross-sectional	60820 participants (men 29412), 59% aged < 20 y	Screening questionnaire and neurological exam	5/100,000	NA	A population survey of neurological diseases
	Community-based	1986-88	3 (2 men) had MND
Harries [132], 1955	Ethiopia	Case series	2(all males) participants	Clinical (no ENMG)	NA	NA
			Age 26 and 30 y
	Hospital-based	1954
Jacquin-cotton [123], 1970	Senegal	Retrospective	6100 participants with neurological disorders	Clinical (No ENMG)	290/100,000		A study of patients with paraplegia in a neurological unit
	Hospital-based	1960-1969	18 (16 men) participants with ALS, age 25-70 y
Piquemal [124], 1982	Ivory coast	Retrospective	4000 participants with neurological disorders	Clinical (no ENMG)	750/100,000	NA	Duration of disease: 3 m to 5 y.
	Hospital-based	1971-80	30 (men 22) participants had ALS, 50% aged <40 y
Collomb [133], 1968	Senegal	Retrospective	18 (17 men) participants with ALS, age 25-70 y	Clinical (no ENMG)	NA	NA	Duration of disease: 4 m to 13 y
	Hospital-based	1960-68
Sene [128], 2004	Senegal Hospital-	Retrospective	33 (19 men) participants with ALS;	El Escorial			Definite ALS: 57%,
							Probable: 30%, Possible ALS: 9%
							Suspect ALS: 3% age at onset 14–67 y.
				(ENMG in half of the patients)
	based	1999-2000					Duration of disease: 6 m to 5 y.

ALS: amyotrophic lateral sclerosis; ENMG: Electroneuromyography; MND: Motor Neuron Disease; NA: Not available; PMA: Progressive muscular atrophy; SMA: Spinal Muscular Atrophy; y: years; m: months.