A new study finds Alzheimer's disease may contribute to nearly as many deaths as heart disease or cancer.
Dr. James Leverenz did not take part in the study, but treats Alzheimer's at Cleveland Clinic.
"Our current estimates of how many people die with Alzheimer's are really much lower than what they really probably are, and so it really opens our eyes as to how important Alzheimer's disease is in the elderly," Leverenz said.
Researchers at Rush University Medical Center studied more than 2,500 people 65 and older. The participants received annual testing for dementia.
Results show that after an average of eight years, nearly half the people had died, and of those, nearly 600 who did not have dementia when the study began developed Alzheimer's disease.
The Centers for Disease Control and Prevention lists Alzheimer's disease as the sixth-leading cause of death in the U.S., but researchers say the findings in this study far exceed the numbers reported by the CDC.
They say their results translate into Alzheimer's contributing to more than 500,000 deaths per year, which is five- to six-times higher than the CDC's number.
Leverenz said studying dementia should be a priority.
"We need to know more about the disease and we need to come up with better ways to treat the disease, and that's going to require more research," he said.
Complete findings for this study are in the journal of the American Academy of Neurology.