Phil Tompkins reference to Dr. Lieberman's article was of interest. I share his desire to have more accurate data. My older brother, who died abour 6 years ago, also had Parkinsons. He lived in North Dakota all his life, except for college and the service. I lived there until I went away to school when I was 17. At this point I have my own theory of what caused our Parkinsons. At this point, of course, there is no scientific backing . It's always difficult for me to know what to ascertain is factual, as it isn't often stated the margin of error, how many cases, etc. Hopefully, more accurate statistics will be available.Good luck in what you are trying to do. Lorraine Jeffe