A new study by Rush University Medical Center in Chicago discovered that more people may die from Alzheimer's than previously thought. The disease is currently the sixth leading cause of death among Americans; however, the results of the study may launch it to the third leading cause behind heart disease and cancer. 

Nearly 84,000 people died as a result of Alzheimer's disease in 2010, according to death certificates. The New York Times said the number should be closer to 500,000 in 2010, when accounting for deaths in which Alzheimer's was an underlying cause.

For the study, researchers analyzed data from 2,566 people age 65 and older. Participants were given annual testing for dementia. After an average of eight years, 1,090 participants died and 559 who were healthy when the study began developed Alzheimer's. 

"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," said study author Bryan James of Rush University Medical Center in Chicago. 

The death rate for those who are between the ages of 75 and 84 is four times higher after an Alzheimer's diagnosis and three times higher in individuals who are age 85 and older.