PD apparently has a lot of causes, age and toxicity from various sources, being some of them. It might be an overlooked coincidence that PD was rarely observed before the industrial revolution and that solvents and other chemicals use increased along with sugar consumption. http://www.webmedcentral.com/article_view/1132

Sucrose, or table sugar consists of glucose and fructose. Consumption in Dr. Parkinson's day was a small fraction of today's intake. http://articles.businessinsider.com/...apita-american

Sugar might be part of the story or have no relationship at all but I find it interesting.