United States – the team of Dr. German,  from the University of Southwestern in Dallas, found that people with Parkinson’s disease had a higher rate of pesticides in the blood than a healthy person or those with Alzheimer’s disease.

The study focused on the research of fifteen organochlorine pesticides in the blood of 113 people aged 50 to 89 years. Fifty of the participants suffered from Parkinson’s disease, twenty of Alzheimer’s disease and forty were in good health.

Researchers have discovered a specific pesticide, beta-HCH in the blood of 76% of people suffering from Parkinson’s disease, 40% of healthy people and 30% of people suffering from Alzheimer’s disease.

Organochlorine pesticides were heavily used in the years 1950 to 1970. Their stability makes them persistent pollutants that contaminate ecosystems in the long term. Their use is banned in many countries because of their high toxicity.

The highest levels of beta-HCH were released into the air, water and food when Parkinson’s patients were between 20 to 40 years old, said Dr. German. If the link between pesticides and Parkinson’s disease has been proven, other pesticides may also be involved.

Another organochlorine pesticide called DDT is particularly known for attacking the same nerve cells in the brain than those destroyed by Parkinson’s disease.