Parkinson's is a progressive brain disorder that is almost always fatal, but the suffering can go on for years. The disease usually strikes people over age 60, but a few people get it before they reach 40. More than a million Americans are living with the disease at any one time.
Parkinson's begins when the brain cells which produce dopamine begin to die. Dopamine serves as a chemical messenger helping to control muscle activities. Loss of dopamine gives rise to stiffness, tremor, slow movement, difficulty with balance, difficulty walking, a stooped-over, shuffling gait. As the disease progresses, the patient may develop difficulty speaking, symptoms of senility (dementia) similar to Alzheimer's, and severe depression.
Causes have been debated for 150 years. A breakthrough occurred in the early 1980s when a group of young people developed the symptoms of Parkinson's disease after taking an illegal drug called MPTP, which is similar to the narcotic pain killer meperidine (which is sold under the trade name Demerol). MPTP is also similar in chemical structure to several pesticides and herbicides. Subsequently, symptoms of Parkinson's were induced in monkeys by feeding them MPTP. Early studies began to show a pattern: many people with Parkinson's have a history of exposure to pesticides, especially insecticides and herbicides.
Jan 28, 1999, a genetic cause for most Parkinson's disease was effectively ruled out by the publication of a study of nearly 20,000 identical twins who did not get Parkinson's any more often than two unrelated individuals. The researchers reported that, “genetic factors appear to be important when [Parkinson's] disease begins at or before age 50.” Fewer than 10% come into this category.
That leaves environmental chemicals as the culprit for the vast majority of Parkinson's. Since the late 1980s, a steady stream of studies from around the world has shown again and again that a common thread among victims of Parkinson's is a history of exposure to insecticides and herbicides.
Most recently a study showed that exposure to industrial solvents is linked to Parkinson's.[2]