Incidence of motor neuron disease/amyotrophic lateral sclerosis in South Africa: a 4‐year prospective study

Abstract

Background and purpose: Little is known about the epidemiological features of amyotrophic lateral sclerosis (ALS) in sub-Saharan Africa, and data from the region are limited to clinical series or case reports. The aim of the study was to investigate the incidence rate and presentation of ALS in an ethnically diverse region of South Africa. Methods: We performed a 4-year prospective incidence study in the Western Cape Province of South Africa between 1 July 2014 and 30 June 2018, and used a two-source capture-recapture method for case ascertainment. Age-and sex-adjusted incidence rates (ASAIRs) were calculated using the 2010 US population as the reference. Results: A total of 203 incident cases were identified over the study period, resulting in a crude incidence rate (IR) of 1.09 [95% confidence interval (CI) 0.94-1.24] per 100 000 person-years in the at-risk population (aged >15 years). Capture-recapture analysis resulted in an estimated IR of 1.11 (95% CI 1.01-1.22) per 100 000 person-years. The ASAIR was 1.67 (95% CI 1.09-2.26) overall; 1.99 (95% CI 1.60-2.39) for men and 1.37 (95% CI 1.06-1.68) for women. When analysed separately, there was a substantial difference in ASAIRs between the different population groups, with the highest in the European ancestry group (2.62; 95% CI 2.49-2.75), the lowest in the African ancestry group (0.56, 95% CI 0.0-1.23), and an ASAIR in between these two in the mixed ancestry group (1.09, 95% CI 0.80-1.37). Conclusion: The overall incidence of ALS in the Western Cape Province of South Africa appears to be lower than in North African and Western countries, but higher than in Asian countries. As suggested by previous epidemiological studies, ALS may be less frequent in people of African ancestry.

Analysis of incidence of motor neuron disease in England 1998–2019: use of three linked datasets

“…In our study, MND diagnosis was more common in men with a male:female ratio of 1.5:1. The higher incidence in men has been found in many previous studies ( 6 , 7 , 12 , 16 , 17 , 25 , 28 , 34–36 , 38 ).…”

Local ancestry prediction with PyLAE

“…Dependence on ethnicity efficiency has been reported in processes and conditions related to the above-listed pathways: vitamin B6 metabolism ( Gong et al, 2014 ), fatty acid biosynthesis ( Sergeant et al, 2012 ; Ameur et al, 2012 ; Kothapalli, Park & Brenna, 2020 ), resistance to malaria ( Singh & Dhar, 2014 ; Gelabert et al, 2017 ), the prevalence of viral myocarditis ( Shaboodien et al, 2013 ) and amyotrophic lateral sclerosis ( Rechtman et al, 2015 ; Henning et al, 2021 ). According to recent studies ( Nédélec et al, 2016 ; Singh et al, 2020 ), individuals with African ancestry have a stronger inflammatory response and reduced intracellular bacterial growth.…”

Local Ancestry Prediction withPyLAE

“…Dependence on ethnicity efficiency has been reported in processes and conditions related to the above listed pathways: vitamin B6 metabolism [26], fatty acid biosynthesis [27–29], resistance to malaria [30, 31], prevalence of viral myocarditis [32, 33] and amyotrophic lateral sclerosis [34, 35]. According to recent studies [31, 36], individuals with African ancestry have a stronger inflammatory response and reduced intracellular bacterial growth.…”