Alzheimer’s risk much higher in those exposed to banned pesticide: study
Sarah Knapton, The Daily Telegraph, National Post Wire Services | January 28, 2014 | Last Updated: Jan 28 9:52 AM ET
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DDT, a pesticide long banned in Canada — since 1972 — has been linked to a four-fold increase in the risk for Alzheimer's disease, according to a new study in JAMA Neurology.
DDT, a pesticide long banned in Canada — since 1972 — has been linked to a four-fold increase in the risk for Alzheimer's disease, according to a new study in JAMA Neurology.
Exposure to a pesticide banned in Canada in 1972 may have increased the risk of developing Alzheimer’s disease, scientists warn in a new study.
People who were found to have the highest levels of DDT in their system were four times more likely to have the degenerative disease.
DDT (dichlorodiphenyltrichloroethane) was banned as a pesticide worldwide under the Stockholm Convention in 2001 after it was discovered to be dangerous to wildlife and the environment. But researchers found it was still present in bodily tissue decades later, broken down into the chemical compound DDE.
A study has found that people suffering from Alzheimer’s disease had more than four times the level of DDE in their bloodstreams compared with those who did not have the disease.
‘This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease’
The researchers said the preliminary findings suggest the pesticide may contribute to the disease alongside other genetic risk factors.
“This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease,” said Dr. Allan Levey, a co-author. “The magnitude of the effect is strikingly large.” The team compared a group of 86 Alzheimer’s patients with 79 people who did not have the disease.
They found levels of DDE were four times higher in 74 of the Alzheimer’s patients than those without the disease.
Furthermore, patients who were carrying a gene that increases the risk of Alzheimer’s had even more severe cognitive impairment if they had been exposed to high levels of DDE.
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 pesticide was used extensively in agriculture from the 1940s onwards until it was banned. It may be present illegally in imported fruits, vegetables and grains or in fish from contaminated rivers.
About 80% of Americans have traces of DDE in their systems. It can take decades to work its way out of the body, having a half-life of between eight and 10 years and can accumulate over time in the tissues as people age.
“This observation could help explain why age is by far the largest risk factor for Alzheimer’s disease,” said Levey. “The potentially huge public health impact of identifying an avoidable cause of Alzheimer’s disease warrants more study.”
‘The earlier someone is diagnosed, the more options there may be available’
The researchers, writing in JAMA Neurology, suggest that doctors should test for DDE as a predictor of the disease.
“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 the lead author, Jason Richardson.
However, experts and charities said the findings should be treated with caution.
Carol Brayne, a professor at Cambridge University in the U.K., said the research had produced a “very interesting result” but it was too early to come to a conclusion about a link between DDT exposure and Alzheimer’s.
“I would be very cautious indeed about over-interpreting the results at this stage without confirmation from research based on stronger designs,” she said.
Simon Ridley, from the charity Alzheimer’s Research UK, said: “It’s important to note that this research relates to DDT, a pesticide that has not been used in the U.K. since the 1980s.
“While this study suggests a possible connection between DDT and Alzheimer’s, we don’t know whether other factors may account for the results.”
Sarah Knapton, The Daily Telegraph, National Post Wire Services | January 28, 2014 | Last Updated: Jan 28 9:52 AM ET
More from National Post Wire Services
DDT, a pesticide long banned in Canada — since 1972 — has been linked to a four-fold increase in the risk for Alzheimer's disease, according to a new study in JAMA Neurology.
DDT, a pesticide long banned in Canada — since 1972 — has been linked to a four-fold increase in the risk for Alzheimer's disease, according to a new study in JAMA Neurology.
Exposure to a pesticide banned in Canada in 1972 may have increased the risk of developing Alzheimer’s disease, scientists warn in a new study.
People who were found to have the highest levels of DDT in their system were four times more likely to have the degenerative disease.
DDT (dichlorodiphenyltrichloroethane) was banned as a pesticide worldwide under the Stockholm Convention in 2001 after it was discovered to be dangerous to wildlife and the environment. But researchers found it was still present in bodily tissue decades later, broken down into the chemical compound DDE.
A study has found that people suffering from Alzheimer’s disease had more than four times the level of DDE in their bloodstreams compared with those who did not have the disease.
‘This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease’
The researchers said the preliminary findings suggest the pesticide may contribute to the disease alongside other genetic risk factors.
“This is one of the first studies identifying a strong environmental risk factor for Alzheimer’s disease,” said Dr. Allan Levey, a co-author. “The magnitude of the effect is strikingly large.” The team compared a group of 86 Alzheimer’s patients with 79 people who did not have the disease.
They found levels of DDE were four times higher in 74 of the Alzheimer’s patients than those without the disease.
Furthermore, patients who were carrying a gene that increases the risk of Alzheimer’s had even more severe cognitive impairment if they had been exposed to high levels of DDE.
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 pesticide was used extensively in agriculture from the 1940s onwards until it was banned. It may be present illegally in imported fruits, vegetables and grains or in fish from contaminated rivers.
About 80% of Americans have traces of DDE in their systems. It can take decades to work its way out of the body, having a half-life of between eight and 10 years and can accumulate over time in the tissues as people age.
“This observation could help explain why age is by far the largest risk factor for Alzheimer’s disease,” said Levey. “The potentially huge public health impact of identifying an avoidable cause of Alzheimer’s disease warrants more study.”
‘The earlier someone is diagnosed, the more options there may be available’
The researchers, writing in JAMA Neurology, suggest that doctors should test for DDE as a predictor of the disease.
“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 the lead author, Jason Richardson.
However, experts and charities said the findings should be treated with caution.
Carol Brayne, a professor at Cambridge University in the U.K., said the research had produced a “very interesting result” but it was too early to come to a conclusion about a link between DDT exposure and Alzheimer’s.
“I would be very cautious indeed about over-interpreting the results at this stage without confirmation from research based on stronger designs,” she said.
Simon Ridley, from the charity Alzheimer’s Research UK, said: “It’s important to note that this research relates to DDT, a pesticide that has not been used in the U.K. since the 1980s.
“While this study suggests a possible connection between DDT and Alzheimer’s, we don’t know whether other factors may account for the results.”
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