Yesterday I attended the launch of the Dementia Declaration by Paul Burstow, Minister of State for Care Services for the coalition government and the Alzheimer's Society.
During questions, a delegate asked one of the speakers, Prof. Alistair Burns, National Clinical Director for Dementia, if he could comment on reports of the long-term effects of exposure to pesticides on the nervous system and the possible link to Alzheimer's disease in late life.
He said that she had an interesting point and that research was ongoing.
This was news to me and sent me scurrying to the internet to see what I could discover. As expected, there are conflicting views. I found myself wondering about the power and might of the chemicals and pharmaceutical industry lobbies...
But here’s one research study I found.
Research is ongoing at Duke University Medical Center in Durham, N.C. A recent study was presented at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease.
Apparently, findings support evidence of a possible link between environmental toxins and Alzheimer's disease and this may help explain why some people with risk factors for the disease get it, while others do not.
Kathleen M. Hayden PhD has been leading the research and says, "While no cause for Alzheimer's disease has been found, (non-inherited) cases are likely due to a combination of genetic and environmental factors".
Pesticides have been proposed as a possible environmental risk factor, but there are few studies of the effects of ‘occupational pesticides’ on the risk of Alzheimer's disease, she says.
Research suggests that pesticides may affect the release of acetylcholine, a chemical that's important for memory.
Pesticide use has dramatically increased over the past 50 years with more than 18,000 pesticides licensed in the US, where about a billion litres are applied to land and crops each year.
The study involved more than 4,000 residents 65 and older from an agricultural county in Utah who are participating in a larger study of risk factors for Alzheimer's disease.
At the start of study, they were asked if they had ever been exposed to pesticides during their work and if so, which types of pesticide and for how long. Of the total, about 750 participants reported working with pesticides.
A standard test that measures overall cognitive function, including memory, attention span and problem solving, was given at the outset and two other times over a six- to seven-year period.
The study showed that exposure to compounds containing organophosphates increased the risk of dementia – any form of progressive memory impairment that interferes with normal functioning – by 36%. They increased the risk of Alzheimer's dementia by 59%.
Alzheimer's disease * is the most common form of dementia, characterised by brain cell destruction and deterioration of thinking and memory resulting in loss of independent functioning.
Notorious organocholorides include dioxins and DDT. Also known as persistent organic pollutants (POPs), they are known to increase the risk of diabetes, even in people of normal bodyweight. Their slow degrading means that they hang around for many years, both in the environment and in the bodies and brains of the millions of people exposed to them.
These chemical poisons have well understood adverse effects on human health. Interestingly, women can reduce their load of these toxins through breast milk, transferring them to their offspring. This may help explain the much higher proportion of men (89%) with new onset dementia in the study.
Exposure to organochlorines clearly exacts a greater toll, increasing the overall risk of dementia by 60% and Alzheimer's disease a full 70%.
As one US doctor comments, "what's so disturbing about this news is that it will be years before research like this is likely to influence public policy. Industry interests and the 'let's wait until we know for sure' attitude of the scientific and medical communities will continue to be the barriers to a rational approach to policy that protects the health rights of human beings, rather than the profit needs of corporations. The number of paid scientists supported by the chemical industry doesn't help matters".
* In the UK 750,000 people are recorded as having Alzheimers’s disease but this excludes many more who have other dementias, those in care homes and those whose dementia has never been formerly diagnosed.
In America there are 5.3 million people living with Alzheimer's disease. Currently, there are nearly half a million new cases each year, but according to the American Alzheimer's Association, by 2050, there are expected to be nearly a million new cases annually.
Sources: Medecinenet.com; AmericancountryMD.com
Image: Squidoo.com
More about pesky pesticides here:
www.sciencedirect.com Volume 86 Issue 1, May 2001
http://emedicine.medscape.com/article/1175139-overview (effects of exposure to organophosphates)
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240413/ (neuropsychologic effects of long-term exposure to pesticides, 2001)