Exposure to the insecticide DDT (dichloro-diphenyl-trichloroethane) may increase the likelihood of developing Alzheimer’s disease later in life, a study published in JAMA Neurology suggests. Previous studies have linked chronic diseases such as cancer and diabetes to DDT, but this is the first to link the U.S.-banned pesticide to Alzheimer’s disease.
Researchers found that levels of the DDT metabolite, DDE, were 3.8 times higher in patients diagnosed with Alzheimer’s disease than in control subjects. They made the link between DDE and Alzheimer’s by measuring three components: blood serum levels; severity of the patient’s Alzheimer’s disease as measured by the Mini-Mental State Examination (MMSE) and its relation to serum DDE levels; and the reaction of isolated nerve cells to DDE. Treatment of human nerve cells with DDE caused them to increase the production of the amyloid precursor protein that is directly linked to Alzheimer’s disease.
Participants in the study underwent preliminary testing to ensure that they didn’t have symptoms of other dementia-related diseases, and were an average age of 74, while the control subjects were on average 70 years old. These findings may help lead to the development of early biomarkers that can determine whether a person will develop Alzheimer’s disease later in life due to DDT exposure.
“We have additional studies underway that will seek to directly link DDT exposure to Alzheimer’s disease,” says co-author Dwight German, PhD, Professor of Psychiatry at UT Southwestern Medical Center. “If a direct link is made, our hope is to then identify the presence of DDE in blood samples from people at an early age and administer treatments to remove it.” Read the study abstract.