March 5, 2014 -- The number of people who die from Alzheimer’s disease may be five times higher than previously thought, researchers at Rush University Medical Center in Chicago say.
The study’s numbers would make Alzheimer's the third leading cause of death in the U.S., right behind heart disease and cancer. The CDC lists Alzheimer’s as the sixth leading cause of death.
The CDC says 83,494 people died from the disease in 2010. That number is based on death certificates, which often fail to list Alzheimer’s as a contributing cause. The true number of deaths may be more than half a million for Americans, according to the study, which appears today in the journal Neurology.
“Trying to identify a single cause of death may not reflect the reality of dying for many older people, where multiple health issues contribute and lead to a cascade of deterioration of health and function that leads to death,” says lead researcher Bryan James, PhD. “And it’s hard to say which of those conditions is the single cause of death.”
Alzheimer’s causes the brain to decline over time. At first, it affects those parts of the brain responsible for thinking and memory. Eventually, it can lead to problems with feeding and swallowing. This puts people at risk for poor nutrition, dehydration, and infection. At that stage, James says, it can lead to fatal conditions such as pneumonia and heart failure.
“I’m not sure that most people grasp that Alzheimer’s is a fatal disease,” he says. “And it’s leading to a lot more death than we recognized before.”
Death certificates, James says, require a single, immediate cause of death, such as pneumonia or heart failure. While there’s room on the form to write underlying causes, several things often get in the way. For example, the doctor who signs the death certificate may not know the person’s medical history. And, James says, some people with Alzheimer’s never get diagnosed.
A key point James makes is that Alzheimer’s can be at the root of a chain of health problems.
In 2013, Alzheimer’s care cost $203 billion in the U.S. Costs are expected to climb past $1 trillion by 2050.