Exposure to the banned pesticide DDT could increase the risk of Alzheimer's disease, according to a new study The Chicago Tribune reported.

Researchers from Rutgers University found that 80 percent of patients with Alzheimer's had four times the levels of a DDT byproduct in their blood compared with those without the disease.

DDT, a pesticide banned in the United States in the 1970s because of its potential harm to human health, is still found in blood samples "because it can take decades for chemicals to break down," The Chicago Tribune reported.

"We really need more attention on the role of environment and the interaction of your genes and environment for complex diseases such as Alzheimer's," Jason Richardson, an associate professor in the Department of Environmental and Occupational Medicine at the Robert Wood Johnson Medical School at Rutgers University told The Chicago Tribune. "The prevailing thought has always been it's a genetic disease. Unfortunately that hasn't panned out."

Researchers said it remains unclear how DDT and its byproduct is related to the memory-robbing disease, but they suspect that the pesticide affect levels of proteins in the brain that are associated with the plaque that leads to the condition, The Chicago Tribune reported.

For the study, researchers analyzed the blood samples of 86 people with Alzheimer's disease, as well as 79 others without the condition. They also analyzed brain samples of 11 Alzheimer's patients who had died and had previously provided blood samples, Richardson stated in the study.

They found levels of a DDT byproduct in 80 percent of patients with Alzheimer's disease, as wells as 70 percent of those without the condition. Those with Alzheimer's disease had levels 3.8 times higher on average.

"This study demonstrates that there are additional contributors to Alzheimer's disease that must be examined and that may help identify those at risk of developing Alzheimer's," Richardson said in a statement. "It is important because when it comes to diagnosing and treating this and other neurodegenerative diseases, the earlier someone is diagnosed, the more options there may be available."

The study is published in the Jan. 27 issue of the journal JAMA Neurology.