Scientists at Georgetown University in D.C. discovered a new blood test that can predict Alzheimer's Disease.

Researchers analyzed blood samples from more than 500 people age 70 and older as part of a five-year study.

They discovered and validated 10 lipids or fats that detected mental impairment in a three-year time frame, with more than 90 percent accuracy. 

"In this study, we sought to find a set of circulating molecules in the blood of individuals who were cognitively normal, that would allow us to predict who in the next several years will develop Alzheimer's disease," Dr. Howard J. Federoff, vice president for health services at Georgetown medical center said. 

Alzheimer's is the sixth largest leading cause of death in the United States. More than five million Americans have the disease and the number is predicted to double by 2050. 

It is a type of mental deterioration or dementia that cause problems with memory, thinking and behavior. Symptoms slowly develops and gets worse over time. 

Some of the symptoms include difficulty completing familiar tasks at work, home or leisure, trouble understanding visual images and confusion with time and place.

African Americans and Latinos are more likely to develop Alzheimer's and other dementia.

According to the Alzheimer's Association, 65 percent of Latinos age 85 and older develop mental impairments. For African Americans, the number is 58 percent. 

Research suggest longer life spans and higher risks for cardiovascular disease are reasons why Alzheimer's is prevalent among the two racial groups. 

Cardiovascular and Alzheimer's can be linked together. Excess amounts of cholesterol in the blood eventually land in the brain. 

"The heart is the organ that supplies blood and other important elements to parts of the body, the brain is one of the first," Larry Sparks, medical examiner, said to ABC News. 

Federoff claimed past efforts to develop drugs for Alzheimer's failed because researchers examined patients who already had the disease. 

"This is a very exciting time, this observation suggest we can enroll and test those at risk not those who already have the disease and might be able to delay a group of individuals from developing Alzheimer's disease," Federoff said.