Golf Course Proximity and Parkinson’s Risk
Environmental Exposure as a Driver of Neurodegeneration
A study published in JAMA Network Open found that people living within a few miles of a golf course faced a significantly higher risk of Parkinson’s disease. Risk increased with proximity, with the highest odds of Parkinson’s observed among those living closest to the golf course boundary. In areas with vulnerable groundwater—regions defined by shallow bedrock, coarse soils, or karst geology that allow contaminants to move quickly into water supplies—the presence of a golf course in the water service area was associated with even higher odds.
John, my late husband, caddied through high school and college and was on the course all day. Of course at the time, not much thought was given to what chemicals lingered on the grass or floated in the air. But after years of tracing Parkinson’s triggers, I now read studies like this as evidence of a larger system failing to account for unseen risks.
Researchers analyzed over 400 new Parkinson’s cases and 5,000 controls using data from communities in Minnesota and Wisconsin. These were the results:
A total of 419 incident PD cases were identified (median [IQR] age, 73 [65-80] years; 257 male [61.3%]) with 5113 matched controls (median [IQR] age, 72 [65-79] years; 3043 male [59.5%]; 4504 White [88.1%]). After adjusting for patient demographics and neighborhood characteristics, living within 1 mile of a golf course was associated with 126% increased odds of developing PD compared with individuals living more than 6 miles away from a golf course (adjusted odds ratio [aOR], 2.26; 95% CI, 1.09-4.70). Individuals living within water service areas with a golf course had nearly double the odds of PD compared with individuals in water service areas without golf courses (aOR, 1.96; 95% CI, 1.20-3.23) and 49% greater odds compared with individuals with private wells (aOR, 1.49; 95% CI, 1.05-2.13). Additionally, individuals living in water service areas with a golf course in vulnerable groundwater regions had 82% greater odds of developing PD compared with those in nonvulnerable groundwater regions (aOR, 1.82; 95% CI, 1.09-3.03).
The researchers pointed to pesticides, primarily herbicides, insecticides, and fungicides, as the likely cause. These compounds migrate through rain, irrigation, and evaporation, circulating into the air, soil, and groundwater. Multiple environmental studies have documented pesticide residues such as 2,4-D and chlorpyrifos in groundwater and drinking water near golf courses, often exceeding established safety thresholds. For example, a study published in Ground Water Monitoring & Remediation (Cohen et al., 1990) found elevated concentrations of these compounds beneath golf courses in Cape Cod. Additional surveys by the U.S. Geological Survey and local water monitoring agencies have reported similar contamination patterns in turf-managed areas.
What’s Being Used and How Often
To keep golf courses looking flawless, maintenance crews rely on rotating chemical regimens. Starting in the 1970s, courses began adopting broadleaf herbicides and organophosphate insecticides like 2,4-D and chlorpyrifos. By the 1990s and 2000s, courses widely incorporated neonicotinoids, triazole fungicides, and plant growth regulators (PGRs). As for frequency, labels for common turf fungicides such as fluazinam specify re-spray intervals of 7–14 days under peak disease pressure (hot and humid conditions).
Many of these interfere with hormonal and neurological systems. Triazole fungicides and PGRs target cytochrome P450 pathways, which also regulate steroid hormones and cholesterol synthesis in humans. Toxicological studies and regulatory reviews, including those from the U.S. EPA and the European Food Safety Authority, have identified certain triazoles (like propiconazole and paclobutrazol) as potential endocrine disruptors, with evidence of developmental and reproductive toxicity in animal models (EFSA 2013; EPA 2020).
Evidence also links chronic exposure to certain pesticides and fungicides with mitochondrial dysfunction, oxidative stress, and damage to dopamine-producing neurons, which are all observed in Parkinson’s disease pathology. For example, studies have shown that paraquat, a synthetic herbicide, and rotenone, a naturally occurring insecticide derived from tropical plant roots, induce oxidative stress and mitochondrial damage in dopaminergic neurons in animal models (Betarbet et al., 2000; Sherer et al., 2003). Long-term exposure to environmental toxicants has also been associated with shifts in gut microbial composition (Sampson et al., 2016; Valdes et al., 2018). More on that here:
Who’s Most at Risk
Not all exposure is equal. People working on or near golf courses like groundskeepers, maintenance crews, caddies, and even frequent players face higher cumulative risk due to repeated contact with treated turf. Children and pets may also be more vulnerable, given their lower body mass and more frequent skin contact with grass. And for communities whose water supply intersects with golf irrigation runoff, risk may build over years.
Even short exposures like walking barefoot on recently treated grass or inhaling drift during morning spraying can matter, especially when repeated over time.
During the pandemic, John and I started taking a walk early in the morning around the park down the street from our house. We would notice that the ground crews were out early on those mornings, spraying herbicides around the playground equipment and sidewalks. Thankfully, many cities are now changing their requirements for maintenance to prohibit the use of toxic herbicides on public parks.
I see this as well in condo maintenance, especially developments where the grounds are pristine. When I was recently out walking the dogs with my son, I could smell the herbicides in the air as we went by one of the condo developments. He often mentions seeing them outside his condo spraying as well. One of his dogs now has a nasal cancer. Is it related to sniffing the herbicides? There is no way of knowing.
But perhaps we should reconsider the presence of dandelions and clover in parks and neighborhoods as a sign of health? As for the golf course crowd, my advice is don’t live near one and consider taking up another sport. If you must play golf then find out the spraying schedules, don’t play in close proximity, and take a very thorough shower immediately upon finishing play. And make sure you have an extremely robust water filtration system.
With gratitude,
Martha
References:
Krzyzanowski, B., et al. “Proximity to Golf Courses and Risk of Parkinson Disease.” JAMA Network Open, May 2025. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2833716
European Food Safety Authority (EFSA). “Peer Review of the Pesticide Risk Assessment of the Active Substance Paclobutrazol.” EFSA Journal, vol. 11, no. 2, 2013, p. 3060. https://doi.org/10.2903/j.efsa.2013.3060
U.S. Environmental Protection Agency (EPA). Registration Review Draft Human Health Risk Assessment for Propiconazole. 2020. https://downloads.regulations.gov/EPA-HQ-OPP-2015-0459-0074/content.pdf
Betarbet, R., et al. “Chronic Systemic Pesticide Exposure Reproduces Features of Parkinson’s Disease.” Nature Neuroscience, vol. 3, no. 12, 2000, pp. 1301–1306. https://doi.org/10.1038/81834
Sherer, T. B., et al. “Mechanism of Toxicity in Rotenone Models of Parkinson’s Disease.” Journal of Neuroscience, vol. 23, no. 34, 2003, pp. 10756–10764. https://www.jneurosci.org/content/23/34/10756
Sampson, T. R., et al. “Gut Microbiota Regulate Motor Deficits and Neuroinflammation in a Model of Parkinson’s Disease.” Cell, vol. 167, no. 6, 2016, pp. 1469–1480.e12. https://doi.org/10.1016/j.cell.2016.11.018
Valdes, A. M., et al. “Role of the Gut Microbiota in Nutrition and Health.” BMJ, vol. 361, 2018, k2179. https://doi.org/10.1136/bmj.k2179
Thank you for reading! Let’s keep the conversation going.
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