Explained: People living closer to golf course have higher risk of Parkinson's disease

A study published in JAMA Network Open has found that individuals residing within one mile of a golf course have a 126% higher risk of developing Parkinson’s disease compared to those living more than six miles away. The risk remains elevated for those living up to three miles away, indicating a potential dose-response relationship.

The primary suspect? Pesticides. Golf courses often use significant amounts of pesticides to maintain their pristine appearance. These chemicals can become airborne or leach into the groundwater, leading to increased exposure for nearby residents.

The study also highlights concerns about water contamination. Residents who share a water source with a golf course, particularly those relying on groundwater, face nearly double the risk of developing Parkinson’s disease compared to those with separate water sources. This risk is even more pronounced in areas with vulnerable geological features, such as karst topography, which allows for easier movement of contaminants into the water supply.

Nonetheless, the findings underscore the need for public health policies aimed at reducing pesticide exposure, especially in residential areas near golf courses. Implementing stricter regulations on pesticide use and improving water treatment processes could mitigate some of the risks identified in the study.

Anti aging billionaire Bryan Johnson shared on X a screenshot of the study. "It's a good idea to routinely test the water you drink," he wrote.

What pesticides are harmful?

When it comes to golf courses and Parkinson’s disease, the most concerning pesticides are those that have been scientifically linked to neurotoxicity — meaning they can damage or disrupt the nervous system. Here are the main culprits:

Paraquat: Paraquat has been heavily linked to Parkinson’s disease in numerous studies. It kills plant cells through oxidative stress, and researchers believe it may do the same to neurons in the human brain — particularly those involved in motor control. It is banned in over 30 countries (including the EU and China), but still used in the U.S. under restricted conditions. "The US Environmental Protection Agency classifies paraquat as "restricted use."1 This means that it can be used only by people who have licenses. Because paraquat is highly poisonous, the United States requires the following safety measures: Blue dye is added to keep it from being confused with other beverages," the US CDC says.

Chlorpyrifos: It is banned in the U.S. for food crops as of 2021, but may still be used on golf courses or in non-agricultural settings. It is known to disrupt neurotransmitter function, especially acetylcholine. Prenatal and long-term exposure is associated with developmental delays and neurological disorders. It is an organophosphate insecticide used to kill a range of insects.

Maneb and Mancozeb (Dithiocarbamates): These are fungicides often used in landscaping, including on golf courses and are often studied in combination with Paraquat; exposure to both has shown to drastically increase Parkinson’s risk. These chemicals disrupt dopamine production — a key hormone depleted in Parkinson’s patients.

Glyphosate: Although primarily linked to cancer (specifically non-Hodgkin’s lymphoma), emerging research suggests glyphosate might also affect gut health and neurological function — both of which are closely linked to Parkinson’s. It is world’s most widely used herbicide.

This case-control study included patients with incident PD and matched controls from the Rochester Epidemiology Project from 1991 to 2015. Data were analyzed between June and August 2024. A total of 419 incident PD cases were identified.