may cause up to six times as many deaths as what is commonly reported, and may be closer to the number of deaths caused by heart disease and cancer, a study says. The authors suggest that underreporting of dementia may have a negative impact on research priorities in the U.S.
Heart disease and cancer, respectively, are the leading causes of death
, while Alzheimer's falls sixth on the list, according to estimates from the Centers for Disease Control and Prevention
. The CDC ranking is derived from death certificates, which often underreport the numbers of people who die from dementia, said the authors of a study published March 5 in Neurology
. They estimate that the true level of death from the disease is significantly greater.
“The proportion of older persons who die of AD is much higher than the number indicated by death certificates,” study authors wrote. “Our figure suggests that AD may be the third leading cause of death after heart disease and cancer, with nearly as many deaths as chronic lower respiratory diseases, stroke and accidents combined.”
In the eight-year study, researchers followed 2,566 people age 65 and older who had received annual dementia testing. Nearly a fourth of the patients developed Alzheimer's. Of those, about 400 died as a result of the disease. More than one-third of all deaths for patients over age 75 were attributable to Alzheimer's disease, which the authors say translates to about 503,400 Alzheimer's deaths in 2010 from people in that age group, nearly six times higher than the 83,494 reported by the CDC.
A valid estimate of the number of deaths attributable to Alzheimer's would “aid assessment of the societal burden of AD dementia, informing government and private research priorities and the development of the recently enacted National Alzheimer's Plan,” the study said.
The National Plan to address Alzheimer's Disease (PDF)
for fiscal 2014 included a $100 million initiative for research, education and outreach on Alzheimer's disease. For consumers, the direct cost of dementia care
is estimated to be about $109 billion, compared to $102 billion for heart disease and $77 billion for cancer, government economists report.
As baby boomers age, the number of people with the condition is expected to increase significantly, so health officials say the need for treatment is urgent.
Earlier this week, the Alzheimer's Association announced an $8 million grant over four years to support a longitudinal evaluation of amyloid risk being conducted by researchers at three leading universities.
In January, a set of studies released in the New England Journal of Medicine found that two once-promising beta amyloid inhibitors, solanezumab and bapineuzumab, had failed to improve cognition in patients with mild to moderate Alzheimer's disease during Phase 3 clinical trials.
There are 94 medicines in development in the U.S. for Alzheimer's, according to PhRMA's 2013 research and development report. Between 1998 and 2011, 101 attempts to create Alzheimer's drugs were unsuccessful. Only three were approved, and they had very impact on the progression of the disease
. Follow Sabriya Rice on Twitter: @MHSrice