Mortality Attributed to Alzheimer's Larger than Reported

Deaths attributed to Alzheimer's disease dementia are much larger than what is reported on death certificates and may rival heart disease and cancer.

Half a million deaths are attributable to Alzheimer’s disease (AD) dementia in the United States, according to a new study published online in Neurology (March 5, 2014). The new number of deaths, totaling 503,400, is much larger than what is reported on death certificates (<84,000 in 2010) and rivals heart disease and cancer as causes of death.

Bryan D. James, PhD, of the Rush Alzheimer’s Disease Center in Chicago, and colleagues used data from 2,566 people aged 65 years and older (mean, 78.1 years) without dementia at baseline from 2 cohort studies of aging with identical annual diagnostic assessments of dementia. The study followed the patients for 8 years and was able to assess mortality completely and accurately in the group because of a requirement that patients consent to organ donation.

A total of 559 participants (21.8%) without dementia developed AD dementia, and 1,090 (42.2%) died. The mortality hazard ratio for AD dementia was 4.30 (Confidence Interval [CI] = 3.33, 5.58) for ages 75 to 84 years and 2.77 (CI = 2.37, 3.23) for ages 85 years and older.

“The estimates generated by our analysis suggest that deaths from Alzheimer’s disease far exceed the numbers reported by the CDC and those listed on death certificates,” James said in a statement.

The researchers conclude that the annual AD dementia death figures reported on death certificates in the United States do not reflect the true burden of mortality from the disease, which they estimate causes more than a third of all deaths in people aged 75 years and older.

AD dementia and other dementias are likely underreported on death certificates as causes of death because they list an immediate cause of death, such as pneumonia, brought on by Alzheimer’s, the study noted.

“Determining the true effects of dementia in this country is important for raising public awareness and identifying research priorities regarding this epidemic,” James said.

The study was funded in part of the National Institutes of Health.