RENEE MONTAGNE, HOST:
Alzheimer's disease does not just take memories, it takes lives. The disease is now the sixth leading cause of death in the United States. Two new reports out today crunch federal data and show that Alzheimer's deaths are both on the rise and accelerating. NPR's Jon Hamilton has more on why more people are dying of the disease and how it causes death.
JON HAMILTON, BYLINE: One big reason Alzheimer's deaths are going up is that deaths from other causes like heart disease and prostate cancer are going down. Maria Carrillo, a brain scientist with the Alzheimer's Association, says the result is more people surviving into their 70s, 80s and beyond.
MARIA CARILLO: Unfortunately, age is still the greatest risk factor for Alzheimer's disease. And so we're living longer, setting ourselves up for potential Alzheimer's disease.
HAMILTON: Carrillo says it's not always clear whether Alzheimer's caused a particular death because patients tend to have other health problems as well. But she says the overall effect is hard to miss.
CARILLO: If a person is living with Alzheimer's disease in their 70s, it actually doubles their mortality risk.
HAMILTON: A new analysis by the Association found that among 70-year-olds with Alzheimer's, more than 60 percent will die within a decade. Among people the same age who don't have the disease, only about 30 percent will die. And Carrillo says Alzheimer's is the only major cause of death without an effective treatment.
CARILLO: We have made great strides in other diseases by really committing resources to research. We have not done that for Alzheimer's disease and Alzheimer's continues, the mortality rate continues to be on the rise, where breast cancer, prostate cancer, heart disease, HIV, their death rates are going down.
HAMILTON: New statistics from the Centers for Disease Control and Prevention show the same trend. And all of the numbers may underestimate deaths from Alzheimer's. Susan Mitchell is with Harvard and the Hebrew Senior Life Institute for Aging Research.
She says death certificates often blame factors like pneumonia, when the real culprit is dementia. Several years ago, Mitchell co-authored a study that looked at how people die from a disease that attacks nerve cells in the brain.
SUSAN MITCHELL: In the early and middle stages, the changes to those nerve cells mostly affect memory and behavior problems but as the disease progresses toward the end stage, the brain changes eventually affect basic bodily functions.
HAMILTON: Like swallowing, which requires the brain to coordinate a complex sequence of muscular contractions. Mitchell says this often goes awry in patients with late stage Alzheimer's.
MITCHELL: Many of these patients develop problems with the muscles that control their swallowing and that can often lead to a lung infection if the food goes down the wrong way, and that is a common cause of pneumonia.
HAMILTON: Dementia also can affect a person's balance and ability to walk, which raises the risk of falls that result in life-threatening injuries. And damage to the brain itself can cause fatal seizures. But Mitchell says the most common causes of death in people with late-stage Alzheimer's are fevers and infections. She says this is because the disease has eroded the body's defenses.
MITCHELL: The body is so debilitated, frail and weak by the end of dementia that some of the usual immunological and metabolic factors that can protect a healthy body from infections and fevers really become susceptible.
HAMILTON: Mitchell says many families don't understand that Alzheimer's affects the body as well as the mind. So she says health care professionals need to explain this aspect of the disease.
MITCHELL: By understanding dementia as a terminal illness we can much better prepare and counsel families about what to expect at the end stage. And then, most importantly, with that understanding we can help families and providers make decisions on the patient's behalf.
HAMILTON: Mitchell says families who fully understand the late stages of dementia are less likely to request extreme measures to keep patients alive. Jon Hamilton, NPR News.
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