Does Pesticide Exposure Increase Your Risk of Dementia?

Here’s some truly disturbing news from the recent International Conference on Alzheimer’s Disease you need to know about.

According to presenter Kathleen Hayden, PhD:  ”Exposure to pesticides may have long term damaging effects on the nervous system that contribute to the development of Alzheimer’s or other dementias.”

Dr. Hayden is from the Duke University Medical Center in Durham, North Carolina and she based her study on 5092 folks from rural North Carolina who filled out a questionnaire every three years starting in 1995.  The area relies heavily on growing wheat, soybeans, apples, corn and hay, all of which are receive heavy doses of chemical pesticides.  The average age was 75 years and 1080 of the subjects already suffered from dementia.  Out of the 4012 people free of dementia, 743 (19%) were exposed to pesticides and 412 developed dementia during the six year study period.  Of those who progressed to dementia, 85 reported have some exposure to pesticides at some time during their lifetimes.

Analysis showed a statistically significant relationship between the onset of dementia and exposure to organophosphates and organochlorines, common pesticide types.

Organophosphates are the basis of pesticides, herbicides and nerve gases.  They are also used as solvents and plasticizers.  It should not come as a surprise that organochlorines are harmful to brain tissue and memory.  They are nerve poisons with both acute and chronic effects that directly affect acetylcholine, the brain neurotransmitter involved with memory.

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, characterized by brain cell destruction and deterioration of thinking and memory resulting in loss of independent functioning.  In spite of the widespread use of Alzheimer’s drugs, costing billions of dollars, they are mostly useless and a futile waste of money resulting in dashed hopes and benefitting no one but the drug companies and the doctors they pay to tout their products.

Notorious organocholorides include dioxins and DDT.  These are also known as persistent organic pollutants (POPs), discussed in last week’s Bulletin. POPs increase the risk of diabetes, even in people of normal bodyweight. They degrade very slowly, which means they hang around for many years – in the environment and 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 this study.

Exposure to organochlorines clearly exacts a greater toll.  They increase the overall risk of dementia by 60% and Alzheimer’s disease a full 70%.

We need to reflect on several important points.  The study did not take into account the duration or extent of exposure.  Did the people who developed dementia work directly with pesticides on a regular basis over many years, suggesting relatively large doses absorbed frequently over many years? Were exposure doses large but less frequent?  Did the study subjects receive many small doses over time, similar to what may be more common in the larger general population?  These and other questions need to be answered with more studies, according to Dr. Hayden, especially due to increasing use of such chemicals.

What’s so disturbing about this news?  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.