Although it’s been known that Alzheimer’s disease shortens life expectancy, new research indicates that it has an even more devastating effect on the oldest elderly.

Ninety-five-year-olds with Alzheimer’s or other forms of dementia were less likely to survive to 100 than those not afflicted, according to researchers writing in the journal Neurology.

“We found that the effect was even more significant compared with younger elderly,” said lead researcher Dr. Anne Borjesson-Hanson of Goteborg University in Sweden. Dementia accounted for more than twice as many deaths at the upper ages than cardiac diseases and at least six times as many deaths as cancer, she said. It was not clear whether shortfalls in care contributed to the high dementia death rates, she said.