Amyotrophic Lateral Sclerosis (ALS), commonly known as Lou Gehrig’s Disease, is a neurodegenerative disorder. This condition selectively destroys motor neurons—the nerve cells in the brain and spinal cord that control voluntary muscle movement. As these neurons degenerate, the muscles they control weaken and waste away, leading to paralysis. Because ALS progresses rapidly and has a short life expectancy, accurately counting the number of affected individuals is complicated.
Current Prevalence of ALS in the US
Prevalence is defined as the total number of people living with a particular disease at a specific point in time. Because ALS is a rapidly progressive disease with a median survival of two to five years from diagnosis, the number of people living with it is constantly being adjusted by new diagnoses and deaths. Determining this number is a complex task for public health officials.
The most recent comprehensive estimates from the National ALS Registry indicate that the number of people living with the disease in the United States is approximately 33,000 cases as of 2022. This total number translates to an estimated prevalence rate of around 10.1 per 100,000 people in the U.S. population.
This prevalence rate is higher than earlier, less comprehensive estimates, reflecting improvements in case identification and data collection methods. The use of sophisticated statistical modeling helps researchers estimate the number of cases missed by traditional surveillance.
Understanding Annual Incidence Rates
The annual incidence rate refers to the number of new cases of a disease diagnosed within a defined population over a specific period, usually one year. Tracking incidence provides researchers with a clearer picture of the rate at which the disease is emerging, which is valuable for investigating potential risk factors and environmental triggers.
For the United States, the annual incidence of ALS is estimated at approximately 1.44 persons per 100,000 people. This rate means that fewer than two new cases of ALS are diagnosed for every 100,000 individuals each year. The consistency of this incidence rate over time suggests a stable rate of disease onset.
The incidence rate tends to increase sharply with age, peaking in the later decades of life before declining slightly in the oldest age groups. This pattern is characteristic of many neurodegenerative conditions.
Demographic Characteristics of Affected Individuals
ALS does not affect all demographic groups equally, with clear differences observed across age, sex, and race. Age is the strongest known demographic risk factor for the disease, with the average age of symptom onset typically falling between 55 and 65 years old. Cases of ALS diagnosed in people under the age of 40 are uncommon. The highest prevalence is consistently observed in the 60 to 69 age bracket.
A notable sex disparity exists in ALS, with men being diagnosed more frequently than women. Historically, the male-to-female ratio has been reported to be approximately 1.5 to 1. This means that for every three men diagnosed with ALS, only two women receive a diagnosis.
Regarding race and ethnicity, data indicates that non-Hispanic White populations in the U.S. have the highest prevalence and incidence rates of ALS. Prevalence rates among White individuals have been reported to be nearly double those found in Black individuals.
The Role of the National ALS Registry
The statistics cited regarding the number of people with ALS are primarily generated and maintained by the National ALS Registry, a federally mandated program. Established by Congress, the Registry is managed by the Agency for Toxic Substances and Disease Registry, which is part of the Centers for Disease Control and Prevention. Its core function is to systematically collect, manage, and analyze data on ALS patients nationwide.
The Registry uses a two-pronged approach to identify and count cases, maximizing the accuracy of its estimates. First, it extracts data from existing national administrative databases, such as Medicare, Medicaid, and the Veterans Health Administration. Second, it offers a secure web portal for individuals with ALS to voluntarily enroll and provide additional health information, capturing cases that might otherwise be missed.
This comprehensive data collection allows researchers to quantify the disease’s presence in the U.S. population and to study potential risk factors. By providing a centralized source of information, the Registry serves as a crucial resource for scientists seeking to understand the disease’s causes and develop effective treatments.