Geographic Distribution of Amyotrophic Lateral Sclerosis (ALS) in the Chicagoland Area
Objective:
To examine changes in ALS incidence in the Chicagoland area from 2007 to 2022 and to identify any geographical clusters.
Background:
ALS is a neurodegenerative disease that affects motor neuron function, leading to progressive muscle weakness. Majority of cases are sporadic and environmental factors have been implicated. Geographical clusters of ALS can help guide future research in identifying environmental exposures. In this study, we used a large patient data registry to examine changes in the number of ALS cases reported over time and to identify any geographical clusters in the Chicagoland area.
Design/Methods:
Data on 1,761 patients registered with the ALS United Greater Chicago Chapter were analyzed from 2007 to 2022. The total number of unique registered cases per year was used to determine trends in the number of reported cases over time. Patients were divided into different age groups to examine age of onset. Lastly, the number of cases reported in different zip codes were used to identify any geographical clusters, and using local census data relative incidence rates were calculated.
Results:
The registry data indicated a statistically significant increase in registered cases over time (p<0.0001). The majority of cases observed were in the 61-70 (584) and 71-80 (411) age groups. A number of geographical clusters were identified in the greater Chicago area and northern suburbs.
Conclusions:
An increase in the registered number of ALS cases was seen with a higher density of cases for some zip codes in the Chicagoland area. Limitations of this study include utilizing one data registry, albeit a large one, which would not account for all ALS cases in the area. Future investigations to assess the potential environmental risk factors contributing to differences in geographic distribution of ALS cases may be considered.