A new study has found that more people die from Alzheimer's disease than what was previously thought, making the disease almost as lethal as two of the biggest killers in the United States: heart disease and cancer.
In a new study published in the journal, Neurology, on March 5, researchers followed more than 2,000 individuals who were 65 years old and over who were tested yearly for dementia. A total of 559 among them developed Alzheimer's disease during the course of the study and 400 died from the disease.
When statistically extrapolated, the researchers said that the number could be translated to about 503,000 Alzheimer's deaths in the U.S. per year, which is six times higher than the report by the Centers for Disease Control and Prevention (CDC) based on death certificates.
"A larger number of deaths are attributable to AD dementia in the United States each year than the number (<84,000 in 2010) reported on death certificates," the researchers reported.
James Leverenz, of the Cleveland Clinic Lou Ruvo Center for Brain Health in Ohio, pointed out that dementia is the underlying cause of many immediate causes of death. Severe dementia, for instance, causes swallowing problems which lead to malnutrition and pneumonia. He said it may be difficult to estimate the number of Alzheimer's death because the immediate cause of death is often written on the death certificate and not dementia.
"Death certificates are well known to underreport deaths from Alzheimer's and other types of dementia," said study author Bryan James, an epidemiologist at the Rush Alzheimer's Disease Center in Chicago. "The more immediate causes of death, such as pneumonia or heart attack, are usually listed, and the underlying causes of death are usually left off."
The CDC reported that heart disease is the leading cause of death in the U.S. with mortality rate of 597,689 per year followed by cancer (574,743) and chronic lower respiratory diseases (138,080). The agency listed Alzheimer's disease at sixth place with 83,494 mortality rate per year. Based on the new study, however, Alzheimer's disease causes more than 500,000 deaths per year and should be placed third instead of sixth.
"Understanding that AD may contribute to almost as many deaths as the two leading killers in America, heart disease and cancer, is an eye-opening figure that may convince the public and policy makers that AD funding should be increased," James said. "The aging of the baby boomer population means more people living with Alzheimer's disease, which in turn means more people dying from Alzheimer's disease since no effective treatment or cure exists."
