Glen Campbell went public in June 2011 with the news that he has Alzheimer's disease

Glen Campbell went public in June 2011 with the news that he has Alzheimer's disease, and he's marked the twilight of his life with a surprisingly ambitious project. The country singer's final, revealing album, 'Ghost on the Canvas. Country music legend Glen Campbell has died at age 81 following a long battle with Alzheimer's disease, his family announced today. Campbell was diagnosed with Alzheimer's disease in 2011, at the age of 75, according to Rolling Stone. Later that year, he announced he was retiring because of his illness, and began a farewell tour that included 151 shows, Rolling Stone said. Although Alzheimer's disease shortens people's life spans, it is usually not the direct cause of a person's death, according to the Alzheimer's Society, a charity in the United Kingdom for people with dementia. Rather, people die from complications from the illness, such as infections or blood clots.