Exposure to pesticides that are widely used for malaria control , DDT , can increase the chances of developing Alzheimer's disease , say researchers in the U.S. .
A study published in the JAMA journal Neurology shows the body of patients with Alzheimer's disease have high levels of DDT was four times higher than the average healthy person .
Alzheimer's Research UK says more evidence needed to prove DDT role in triggering dementia .
DDT is a pesticide that was originally used for malaria control at the end of World War II and later used to protect commercial crops .
Some countries still using pesticides to control malaria .
United States banned the use of this pesticide in 1972 . Many other countries do the same thing . Nevertheless WHO still recommends the use of DDT to control malaria .
Questions about the impact of pesticides on human health of this kind is already emerging . Not only for humans , but also the impact on the wider environment , in particular for natural predators living around the plant .
Still need proof
DDT can be broken down in the human body into a substance called DDE .
The team at Rutgers University and Emory University tested the blood levels of DDE in 86 Alzheimer's disease and compared the results with 79 healthy people of all ages and backgrounds the same .
The results showed those with Alzheimer's disease have high levels of DDE 3.8 times higher rate .
Researchers believe the chemicals that increase the risk of contracting Alzheimer's may contribute to the development of amyloid plaques in the brain . This plaque contributes to death of brain cells .
Professor Allan Levey , director of the Alzheimer's Disease Research Center at Emory , said , " It was one of the first studies to identify environmental risk factors strongly associated Alzheimer's . Influence is very large , comparable to the size of the genetic risk factors . "
While Dr Simon Ridley , head of research at the charity Alzheimer's Research UK , said , "It takes a lot more research to prove the existence of the effect of pesticides on the disease . "