<unk>  is the most common motor neuron disease in adults and the third most common neurodegenerative disease after Alzheimer's disease and Parkinson's disease. Worldwide the number of people who develop<unk>  yearly is estimated to be 1.9 people per 100,000 per year, while the number of people who have<unk>  at any given time is estimated to be about 4.5 people per 100,000. In Europe, the number of new cases a year is about 2.6 people per 100,000, while the number affected is 7–9 people per 100,000. The lifetime risk of developing<unk>  is 1:350 for European men and 1:400 for European women. Men have a higher risk mainly because spinal-onset<unk>  is more common in men than women. The number of those with<unk>  in the United States in 2015 was 5.2 people per 100,000, and was higher in whites, males, and people over 60 years old. The number of new cases is about 0.8 people per 100,000 per year in east Asia and about 0.7 people per 100,000 per year in south Asia. About 80% of<unk>  epidemiology studies have been conducted in Europe and the United States, mostly in people of northern European descent. There is not enough information to determine the rates of<unk>  in much of the world, including Africa, parts of Asia, India, Russia, and South America. There are several geographic clusters in the Western Pacific where the prevalence of<unk>  was reported to be 50–100 times higher than the rest of the world, including Guam, the Kii Peninsula of Japan, and Western New Guinea. The incidence in these areas has decreased since the 1960s; the cause remains unknown. People of all races and ethnic backgrounds may be affected by<unk> , but it is more common in whites than in Africans, Asians, or Hispanics. In the United States in 2015, the prevalence of<unk>  in whites was 5.4 people per 100,000, while the prevalence in blacks was 2.3 people per 100,000. The Midwest had the highest prevalence of the four US Census regions with 5.5 people per 100,000, followed by the Northeast (5.1), the South (4.7), and the West (4.4). The Midwest and Northeast likely had a higher prevalence of<unk>  because they have a higher proportion of whites than the South and West. Ethnically mixed populations may be at a lower risk of developing<unk> ; a study in Cuba found that people of mixed ancestry were less likely to die from<unk>  than whites or blacks. There are<unk> o differences in the genetics of<unk>  between different ethnic groups; the most common<unk>  gene in Europe is C9orf72, followed by SOD1, TARDBP, and FUS, while the most common<unk>  gene in Asia is SOD1, followed by FUS, C9orf72, and TARDBP. Estimated prevalence of<unk>  in the United States by age group, 2012–2015<unk>  can affect people at any age, but the peak incidence is between 50 and 75 years and decreases dramatically after 80 years. The reason for the decreased incidence in the elderly is unclear. One thought is that people who survive into their 80s may not be genetically susceptible to developing<unk> ; alternatively,<unk>  in the elderly might go undiagnosed because of comorbidities (other diseases they have), difficulty seeing a neurologist, or dying quickly from an aggressive form of<unk> . In the United States in 2015, the lowest prevalence was in the 18–39 age group, while the highest prevalence was in the 70–79 age group. Sporadic<unk>  usually starts around the ages of 58 to 63 years, while familial<unk>  starts earlier, usually around 47 to 52 years. The number of<unk>  cases worldwide is projected to increase from 222,801 in 2015 to 376,674 in 2040, an increase of 69%. This will largely be due to the aging of the world's population, especially in developing countries.
Amyotrophic lateral sclerosis
Botulism
Tropical ataxic neuropathy
Juvenile primary lateral sclerosis
Vascular myelopathy
Multiple system atrophy
Surfer's myelopathy
Lambert–Eaton myasthenic syndrome