TUESDAY, April 26 (HealthDay News) -- Seniors who are “housebound” seem to have nearly double the risk of developing Alzheimer’s disease, a new study suggests. The research doesn’t prove that being confined to the house causes dementia, and other factors could explain the association. Still, the findings raise questions about the possible cost of isolation, said lead investigator Bryan D. James, a postdoctoral fellow at Rush Alzheimer’s Disease Center in Chicago.