Mapping cases of Parkinson's disease, the second-most common neurodegenerative disease behind Alzheimer's, might prove illuminating. We could see where the progressive condition is more common and maybe get some potential research leads.
Scientists at Washington University in St. Louis have done this. Using data on Medicare recipients, they've learned that the Northeast and the Midwest have significantly more cases of the disease, and that whites and Latinos are more likely to develop it than are blacks and Asians.
Here are the very brief abstract for the study, published in Neuroepidemiology, and the news release (complete with the aforementioned and enlightening map). The lead author suspects a connection to environmental risk factors, specifically to chemicals used in agriculture and metal processing.
For a primer on Parkinson's disease, there's this overview from the National Parkinson Foundation. It begins:
Parkinson's disease (PD) was first described in 1817 by Dr. James Parkinson, a British physician, for whom the disease was named. It is a disease that is characterized by four major features:
-- Rest tremor of a limb (shaking with the limb at rest).
-- Slowness of movement (bradykinesia).
-- Rigidity (stiffness, increased resistance to passive movement) of the limbs or trunk.
-- Poor balance (postural instability).
-- Tami Dennis