A new report suggests that Alzheimer’s disease may kill far more people than previously thought, making it one of the leading causes of death in the United States, along with heart disease and cancer.
Alzheimer’s is currently listed as the sixth leading cause of death among Americans. But the new analysis suggests that the disease often goes unreported on death certificates and medical records, and that the actual number of people who die of Alzheimer’s may be five to six times higher than current estimates.
While most people think of Alzheimer’s as a brain illness that affects primarily memory and thinking, the disease takes a heavy toll on the whole body. Eventually major organs can shut down, bringing on death an average of three to nine years after a diagnosis is first made.
“Death certificates often list the immediate cause of death, such as pneumonia, rather than listing dementia as an underlying cause,” said study author Bryan D. James of Rush University Medical Center in Chicago. But ill seniors often have multiple health issues, only one of which is Alzheimer’s disease.
For the study, researchers followed 2,566 elderly men and women, average age 78, for an average of eight years. They were part of the Religious Orders Study and the Rush Memory and Aging Project, an ongoing study of aging and dementia. All received annual testing for Alzheimer’s and other forms of dementia.
During the study period, over one in five, or 559 of the study participants, were diagnosed with Alzheimer’s. This diagnosis was confirmed during autopsy in about 90 percent of those who were thought to have the disease. Over all, 1,090 of the study participants died.
Men and women aged 75 and older who had been given a diagnosis of Alzheimer’s were three to four times more likely to have died than those who had remained dementia-free. The findings, published in the journal Neurology, from the American Academy of Neurology, suggest that Alzheimer’s is a major contributor to mortality.
Dr. James, the study leader, said that based on these results and statistical projections of the population at large, more than 500,000 Americans aged 75 and older likely had died of Alzheimer’s in 2010. This number is five to times higher than official estimates from the Centers for Disease Control and Prevention, which reported that 83,494 people, or less than 5 percent of the elderly population, had died of Alzheimer’s that year.
“Determining the true effects of dementia in this country is important for raising public awareness and identifying research priorities regarding this epidemic,” said Dr. James.
Currently, heart disease is listed as the leading cause of death in the United States, followed by cancer, respiratory diseases, stroke and accidents, then Alzheimer’s.
Source: Bryan D. James, PhD, Sue E. Leurgans, PhD, Liesi E. Hebert, ScD, et al: “Contribution of Alzheimer Disease to Mortality in the United States.” Neurology, Vol. 82, pages 1-6, February 2014.