Studies line up on Parkinson's and pesticides link

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Evidence that pesticides can cause Parkinson's disease is stronger than it has ever been after a meeting of experts who have put together links in animals and people, scientists say.

One study shows that farm workers who used the common weedkiller paraquat had two to three times the normal risk of Parkinson's, a degenerative brain disease that eventually paralyzes patients.

A second study shows that animals exposed to paraquat have a build-up of a protein called alpha-synuclein in their brains. This protein has been linked to Parkinson's in the past.

A third piece of the puzzle shows that this buildup of protein kills the same brain cells affected in Parkinson's.

"All of these pieces really look like they are coming together now," Dr. William Langston, founder of the non-profit Parkinson's Institute, told Reuters.

Langston and colleagues said they were energized by research presented at the Parkinson's Disease Environmental Research meeting in Monterey, California, earlier this month.

Parkinson's disease, which affects more than 1 million patients in the United States, is marked by the death of brain cells that produce dopamine.

Dopamine is a neurotransmitter, or message-carrying chemical, associated with movement. Drugs can delay symptoms for a while but there is no good treatment and no cure.