Exposure to Banned Pesticide Raises Risk of Alzheimer’s, Study Suggests

Rebecca Lewis January 30, 2014

Exposure to once a commonly used pesticide may increase one’s risk of developing Alzheimer’s disease. The study, published in the journal JAMA Neurology, showed that patients with Alzheimer’s had four times as much DDT lingering in the body as healthy people.

DDT (dichlorodiphenyltrichloroethane) was a massively successful pesticide, initially used to control malaria at the end of World War II and then to protect crops in commercial agriculture. But due to human health and environmental concerns, it was banned over 30 years ago in Britain, US and some other countries.

Now, researchers from Rutgers University and Emory University found it is still present in bodily tissue decades later, broken down into the chemical compound DDE. They note that the use of the pesticide in other countries is of particular concern to those over the age of 60.

The team tested the DDE levels in the blood of 86 people with Alzheimer’s disease and compared the results with 79 healthy people of a similar age and background. Their findings showed that people with Alzheimer’s had 3.8 times the level of the said compound.

DDE and Alzheimer’s

The researchers believe that DDE may be involved in the development of amyloid plaques in the brain, a hallmark of the disease, which contribute to the death of brain cells.

"This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease.” Prof Allan Levey of the Alzheimer’s Disease Research Centre at Emory said. "The magnitude of the effect is strikingly large; it is comparable in size to the most common genetic risk factor for late-onset Alzheimer’s."

Previous studies of brain cells have shown that the compound increases levels of ’sticky’ amyloid proteins which are thought to build up the damaging plaques associated with the disease. The researchers note that it may still be present in imported fruits and vegetables, and in fish which have swum in contaminated waters. They add that over 80 per cent of Americans have traces of DDE in their system and it could take decades before the compound gets completely eliminated from their system.

Important Implications

The researchers said their data may lead to earlier diagnosis and improved outcome. “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,” said lead author Prof Jason Richardson.

However, experts and charities warned that the findings should be treated with caution until larger studies were carried out.

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Pesticide DDT May Up Risk for Alzheimer’s