Dementia, known in the past as senility, is more than just a disease of the brain. "It causes a gradual deterioration of not only the mind but the body as well," Mitchell said. "The body gets weaker and weaker. Just like in cancer or AIDS, for example, people may ultimately have a pneumonia at the end."
Lack of understanding about the deadliness of dementia could lead relatives to push for unnecessary treatment in the last days of life, Mitchell said.
"Let's say someone gets pneumonia or eating problems when they're in this final stage. Understanding that they're dying of this terminal illness, that they're still going to have this disease they'll ultimately succumb to, might lead them to take a less aggressive approach," she said.
Dr. Claudia Kawas, a member of the Alzheimer's Association medical and scientific advisory council, said the study findings aren't surprising. The number of deaths caused by dementia could be double those reported in statistics -- or perhaps three to four times as high, she said.
As the U.S. population ages, it's crucial to develop correct statistics about health care, said Kawas, a professor of neurology and neurobiology and behavior at the University of California, Irvine. "This study says you're not going to be able to project them accurately" if the death certificates are used.
Learn more about Alzheimer's disease from the Alzheimer's Association.
SOURCES: Susan Mitchell, M.D., associate professor of medicine, Harvard Medical School, and senior scientist, Hebrew SeniorLife, Boston; Claudia Kawas, M.D., member, Alzheimer's Association medical and scientific advisory counci
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