Most people with ALS get sick between the ages of 45 and 75, but because there are different types of ALS, symptoms and disease course can vary.
About 10 percent of those affected have what is known as familial ALS, i.e. there is an altered genetic predisposition in the family.
In the other 90 percent of those affected, today we do not know the cause of the disease, it is so-called sporadic ALS. For this group, there is a proven association with, among other things, old age, male sex, smoking and relatives with nervous disorders.
Other factors that can cause increased risk include some types of heavy physical activity and damage to the brain, such as in athletes in contact sports.
By the age of 65, there are twice as many men as women with ALS. After the age of 70, there are about as many men as women who fall ill.