It is generally estimated there are approximately 30,000 in the United States living with ALS at any given time; the number is estimated at around 450,000 worldwide. These numbers are hard to accurately determine because there is no standard measure, the disease takes time to diagnose, and availability of adequate medical care for neurological diseases varies from country to country. Generally speaking, someone is diagnosed with ALS every 90 minutes. There are many national efforts to count and/or register individuals living with ALS, including one in the US.
ALS is considered to be fatal, with many patients succumbing to respiratory failure and other complications of the disease. Most people with ALS live 3-5 years after their first signs of disease, but progression varies, and up to 10% are estimated to survive 10 years or longer. Survival can also be extended if a patient opts for mechanical ventilation.
PLS neurodegeneration is restricted to only upper motor neurons, while an ALS diagnosis requires the observation of progressive loss of both upper and lower motor neurons. Publications suggest that PLS tends to be a slowly progressing disease, but progression may advance to involve lower motor neurons as well. Thus, PLS diagnosis is often altered to ALS.
A comprehensive report
conducted by the National Academies' Institute of Medicine (IOM) in 2006 supports the association between service in the U.S. military and increased risk of developing ALS
. The IOM was charged with reviewing and evaluating all relevant scientific literature on ALS and veterans. It concluded that there exists "suggestive evidence of an association between military service and later development of ALS."
Since 2000, studies have been conducted to assess the ALS incidence rate in Gulf War veterans. Most notably, a study jointly funded by the US Department of Veterans Affairs and the US Department of Defense concluded that those deployed in the first Gulf War (1990-1991) were twice as likely to develop ALS as their non-deployed counterparts, and potentially, at younger ages. Air Force veterans, it determined, faced the highest risk, at 2.7 times that of those not serving.
In 2005, The Harvard School of Public Health broadened the case for ALS's military relevance. Its epidemiological study
found that men with a history of any military service
in the last century were approximately 53% more likely
to die of ALS than men in the general population. In July 2008, in response to the evidence, Secretary of Veterans Affairs Dr. James B. Peake announced that ALS is to be considered a presumptively compensable illness for all veterans with 90 days or more of continuously active service in the military.