DDT — a World War II-era pesticide used extensively in the U.S. until it was banned in 1972 — accumulates in people’s bodies and persists for decades. Alzeimer's joins a long list of associated health harms.
In this new study, conducted by the Medical School in Rutgers University, researchers analyzed blood samples of 86 people diagnosed with Alzheimer’s and 79 people without the condition. They also analyzed brain samples of 11 Alzheimer’s patients who had passed away and had previously provided blood samples.
Researchers found the DDT breakdown product DDE in 80% of those with Alzheimer’s and 70% of those without the disease. And those with Alzheimer’s had DDE levels 3.8 times higher on average. The study also showed that those with the Alzheimer’s gene ApoE4 and high levels of DDE scored the lowest on cognition tests.
Jason R. Richardson, PhD, the lead study author, said:
“I think these results demonstrate that more attention should be focused on potential environmental contributors and their interaction with genetic susceptibility”
According to the Alzheimer’s Association, this disease affects more than 5 million people in the U.S., with projections that this figure could triple by 2050.
This new study adds to a growing body of research linking pesticide exposure to memory loss and other types of cognitive and physical decline. And these harms disproportionately impact those routinely exposed to pesticides through their work, including farmers, farmworkers and gardeners.
A 2008 report titled "Environmental Threats to Healthy Aging" from the Science and Environmental Health Network — along with the Greater Boston chapter of Physicians for Social Responsibility — highlights the many studies connecting occupational exposures to neurotoxic pesticides with an increased risk of cognitive decline, dementia or Alzheimer’s disease. Studies also link pesticide exposure to increased threat of several diseases impacting older adults, like Parkinson’s Disease and diabetes.
While DDT is no longer used in the U.S., its wide-reaching impacts continue to be unveiled. And as science continues to show, exposures to pesticides and other environmental toxins — even at low-levels — can lead to the onset of serious conditions later in life. It's time to shift our food system away from reliance on hazardous pesticides in order to safeguard the health of youth and older adults alike.