An estimated 5.5 million Americans of all ages have Alzheimer's disease. Of the estimated 5.5 million Americans living with Alzheimer's dementia in 2017, an estimated 5.3 million are age 65 and older and approximately 200,000 individuals are under age 65 and have younger-onset Alzheimer's. One in 10 people age 65 and older (10 percent) has Alzheimer's dementia.
Major dictionaries. The longest word in any of the major English language dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis, a word that refers to a lung disease contracted from the inhalation of very fine silica particles, specifically from a volcano; medically, it is the same as silicosis.
2 Contributions. I remember when people claimed that antidisestablishmentarianism  was the longest English word, so it may still be the longest one  beginning with the letter a.   Thâ¦e longest word in the English language which starts with the  letter 'A' is   antidisestablishmentarianism.