Pesticide exposure, coupled with a genetic variant in the body, appears to be associated with an increased risk of Parkinson’s disease in men, according to a study published in this month’s Archives of Neurology.

Parkinson’s disease, which remains incurable, attacks patients’ motor abilities and is characterized by four primary signs:

  1. Tremor (trembling hands, legs, jaw and/or face)
  2. Rigid or stiff limbs and/or trunk
  3. Slowed movements
  4. Impaired balance and coordination

In prior studies, patients exposed to certain pesticides—including organochlorines like DDT—have been shown to develop the disease. Pesticide exposure damages the neurons in the brain that produce dopamine, a critical neurotransmitter.

The cause of Parkinson’s disease is usually multifactorial, note Fabien Dutheil, PhD, and colleagues from L’Université Paris Descartes. In the new study, men with specific gene variants who had been exposed to organochlorine insecticides had a 350% greater chance of developing the disease.

For Your Organic Bookshelf: Getting on Our Nerves: Researchers Find a Connection Between Parkinson’s Disease and Pesticides