Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease impacting motor neurons in the brain and spinal cord. These motor neurons control voluntary muscle movement. Their degeneration leads to a gradual loss of muscle control, affecting an individual’s ability to move, speak, swallow, and eventually breathe.
Understanding ALS Prevalence in the United States
Understanding ALS in the United States involves examining its prevalence and incidence rates. Prevalence refers to the total number of people living with ALS at a specific time, while incidence represents the number of new cases diagnosed annually. According to the National ALS Registry’s 2017 data, an estimated 24,821 individuals were living with ALS in the U.S., a prevalence of approximately 7.7 per 100,000 people. This estimate falls within a range from 5.5 to 9.9 per 100,000, reflecting the complexities of accurately counting cases of a rare disease.
Projections from the National ALS Registry indicate U.S. cases were close to 33,000 in 2022, expected to rise to over 36,000 by 2030. The national average prevalence was 4.4 per 100,000 persons between 2011 and 2018, with geographical variations from 2.6 per 100,000 in Hawaii to 7.8 per 100,000 in Vermont. The annual incidence of ALS in the U.S. is typically around 1.5 to 2 new cases per 100,000 people, with a 2019 estimate from the CDC placing it at 1.44 new persons per 100,000 U.S. population.
Characteristics of Individuals Affected by ALS
ALS primarily affects individuals in middle to late adulthood. The average age at diagnosis is around 55, and the risk of developing ALS generally increases with age. The highest prevalence rates are observed in the 70-79 age group.
Men are more frequently affected by ALS than women, with a male-to-female ratio typically between 1.2:1 and 1.5:1. This gender disparity tends to diminish in individuals over 70. ALS is more common in White individuals and less frequent among African-Americans, Asians, and Hispanic populations in the U.S. Most ALS cases (90-95%) are sporadic, meaning they have no known genetic cause, while 5-10% are familial, indicating genetic inheritance.
Data Collection and the National ALS Registry
The National ALS Registry collects and manages data on ALS prevalence and demographics in the United States. Established by the ALS Registry Act in 2008, this federal program gathers comprehensive information on individuals living with ALS. Its purpose is to accurately estimate the number of new and existing cases, identify who is affected, and pinpoint potential risk factors.
Data are compiled from various sources, including national administrative databases like Medicare and the Veterans Health Administration, supplemented by voluntary self-registrations and detailed surveys completed by individuals with ALS. Accurately counting individuals with a rare disease like ALS presents challenges due to diagnostic delays or incomplete reporting. The Registry addresses this by providing lower, mean, and upper bound estimates to offer a more complete picture of the disease burden. This data collection is essential for researchers to understand the disease’s epidemiology, identify risk factors, and track its progression, supporting new treatments and potential cures.