The U.S. prevalence of amyotrophic lateral sclerosis (ALS) in 2014 was 5.0 per 100,000 people, which was unchanged from 2013, according to researchers. Men, whites, and people 60 and older continue to show the highest rates.
The study, “Prevalence of Amyotrophic Lateral Sclerosis — United States, 2014,” was published in the Morbidity and Mortality Weekly Report of the Centers for Disease Control and Prevention (CDC).
The first effort to estimate ALS prevalence in the U.S. was published for 2010-2011. The present findings from the National ALS Registry represent results from the period Jan. 1 to Dec. 31, 2014. They include Medicare hospice data and ALS prevalence rates by Census region for the first time, the authors observed.
The study used administrative and self-reported data to “better describe the epidemiology of ALS in the United States and to facilitate research,” the authors wrote. It also aimed to describe the demographics of ALS patients and evaluate potential risk factors for the disease.
A total of 15,927 ALS patients were identified across the three national databases — Medicare, Veterans Health Administration, and Veterans Benefits Administration — and also through a web portal where patients can self-register.
Besides the unchanged prevalence from 2013, there were also no increases across different age groups. Patients with the lowest prevalence (0.5 per 100,000) were those ages 18-39, whereas the highest prevalence (20.0 per 100,000) was seen in the 70-79 age group.
As in 2013, ALS was more prevalent in men than in women (6.3 vs. 3.6 per 100,000), and in whites more than blacks (5.4 vs. 2.4 per 100,000).
“ALS has remained more prevalent in whites, males, and persons aged [60 or older]; current patterns are similar to those identified during 2010-2013,” CDC researchers wrote.
Unlike the authors’ initial hypothesis, the inclusion of hospice data did not lead to an increase in ALS prevalence. This may have been due to the prior identification of hospice patients in the three national databases or the web portal.
However, additional years of data are needed to better determine whether ALS rates are changing, the scientists cautioned.
An analysis of disease prevalence by U.S. census regions showed that the Midwest had the highest rate (5.7 per 100,000), followed by the Northeast (5.5), the South (4.7), and the West (4.3).
“The higher ALS prevalence in the Midwest and Northeast likely reflects the higher proportion of whites, compared with the South and West,” the researchers wrote.
In turn, the lowest prevalence in the West is most likely due to the diverse population in states such as California, they added.
Among the study’s limitations, the authors mentioned the possible under-representation of ALS cases in the Registry and the potential duplication of records due to issues such as misspellings of names or data entry errors.
“The National ALS Registry continues to be improved and enhanced, increasing its potential for ALS research and detection of more ALS cases,” the investigators wrote.
Researchers are working to expand nationwide ALS research. The 2017 launch of the National ALS Biorepository within the Registry aims to provide scientists with patient samples representative of the population distribution in the U.S.
They will be paired with risk factor data, such as occupational or military history, to boost research on ALS genetics, biomarkers, and environmental pollutants, the authors wrote.