Alzheimer’s disease (AD) may be the third largest cause of death, behind heart disease and cancer.
More than 500,000 die of AD each year, according to the study “Contribution of Alzheimer Disease to Mortality in the United States.” That’s much higher than the 84,000 estimate by the Centers for Disease Control and Prevention (CDC), which lists dementia as the sixth-largest cause.
“Overall, the data indicate that the proportion of older persons who die of AD is much higher than the number indicated by death certificates, which is less than 5% of all deaths in the elderly,” says the study, published March 12 in the journal Neurology.
Researchers, following about 2,600 people ages 65 and over for an average of eight years, believe that the underreporting starts with how those death certificates are filled out. Dementia progresses over years, causing complications such as malnutrition that can lead to pneumonia.
“These more proximate causes are listed on the death certificate as immediate cause of death, while dementia is often omitted as an underlying cause,” the study states. “Attempting to identify a single cause of death may not capture the reality of the process of dying for most elderly people because multiple factors may contribute to death in the elderly, some proximate and some distal.”
It may be time for the medical profession to embrace the concept of mixed mortality.
“This more nuanced view of ‘cause of death’ is needed for an accurate understanding of the contribution of chronic diseases such as AD to death in rapidly aging populations.”
The data do not include deaths attributed to mild cognitive problems caused by AD “so we likely underestimated the true number of deaths attributable to AD; prior work has found that mild cognitive impairment is associated with mortality.”
However, “even if our estimates of hazard of death were off by a factor of two, this figure would be approximately 200,000, which is still substantially higher than the figure from the CDC.”