Prior studies have established links between poor olfaction and Parkinson's disease, and impaired sense of smell is a common prodromal symptom of Parkinson's disease. The causes and mechanisms of prodromal neurodegeneration are actively being researched. However, environmental exposure to pesticides or other chemicals may trigger or modify the course of neurodegeneration, potentially leading to the development of Parkinson's disease over time. In this episode, Dr. Honglei Chen shares his research on environmental causes of neurodegenerative diseases, focusing particularly on evidence linking olfaction, environmental exposure, and Parkinson’s disease. Better understanding how environmental factors may contribute (alone or in combination with genetic factors) to the pathogenesis of Parkinson's disease may lead to new approaches to prevent or slow the progression of neurodegeneration. Honglei is the MSU Research Foundation Professor of Epidemiology and Biostatistics at Michigan State University. This podcast is geared toward researchers and clinicians. If you live with Parkinson’s or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson’s Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.