Alzheimer’s Kills Many More Than Expected
James and his colleagues looked at the health records of 2,566 volunteers between 1994 and 2013. The volunteers were 65 or older and dementia-free at the start of the study. Nearly three-quarters were women, and close to 90% of them were white. Their average age was 78. In general, they had a higher-than-average level of education and were likely in better-than-average health.
Each participant had yearly medical exams in which they were tested for Alzheimer’s disease and other dementia. Their medical histories were reviewed, and chronic conditions such as heart disease, high blood pressure, and diabetes were noted. They also were asked questions to check on memory, thinking, and how they did tasks. They agreed to allow autopsies at the time of their deaths as well. The researchers followed them for an average of 8 years.
Over the course of the study, 559 participants were diagnosed with Alzheimer’s disease. They lived an average of 4 years after the disease was found. Alzheimer's accounted for one-third of the 1,090 deaths that occurred during the study.
“This,” the researchers write, “translates into more than 500,000 deaths attributable to AD dementia in the United States in 2010.”
“We know that 5 million people have Alzheimer’s disease, that there are no effective treatments for it, and that it’s a fatal disease, so the numbers were not that surprising to us,” James says.
“This study does make the case very strongly that AD accounts for a larger proportion of deaths in any given time period than had been thought,” says Terry Goldberg, PhD. He's the director of research in neurocognition at the Litwin Zucker Alzheimer’s Center at the Feinstein Institute for Medical Research. Goldberg was not involved in the study. “Alzheimer’s may not be the proximal, or immediate, cause of death, but you can often trace it back to AD.”
Neurologist Liana Apostolova, MD, was also impressed by the study. She's an Alzheimer’s researcher at the Mary S. Easton Center at UCLA.
“This is a more realistic estimate of the death toll of AD relative to the one that we can get from the CDC, and knowing how prevalent AD is, the results of the study are not unexpected,” she says.
“The high death rate underscores the lack of a cure,” says Apolostova, who was not connected to the research team. “Many families are affected by this devastating disease, and it robs patients of what makes them uniquely human: their social and intellectual graces. This study will really help raise awareness about Alzheimer’s.”