Does Pesticide Use Increase Rates of Parkinson's Disease? Evidence from Golf Courses

This study examined whether proximity to golf courses raises the risk of Parkinson’s disease (PD). Using Rochester Epidemiology Project data from 1991–2015, the researchers identified 419 PD cases and 5,113 controls. After adjusting for demographics and neighborhood factors, living within one mile of a golf course was associated with a 126% higher likelihood of PD (aOR 2.26). Residents in water service areas with golf courses faced nearly double the odds of PD compared to those in areas without them (aOR 1.96). The risk was greatest in vulnerable groundwater regions, suggesting pesticide contamination as a pathway .

The Policy Scientist’s Perspective

This article addresses an important public health issue: the relationship between pesticide use and the risk of Parkinson’s disease. The findings matter not only for people who live near golf courses but also for communities where environmental exposures may be underestimated. The study makes a clear contribution to the existing literature by using detailed medical and geographic data to show a consistent association. While the evidence is observational and does not prove cause and effect, the results are strong enough to justify more research and policy discussion. This study adds important new knowledge to an understudied environmental risk.

Full Citation and Link to Article

Krzyzanowski, B., Mullan, A. F., Dorsey, E. R., Chirag, S. S., Turcano, P., Camerucci, E., Bower, J. H., & Savica, R. (2025). Proximity to golf courses and risk of Parkinson disease. JAMA Network Open, 8(5), e259198. https://doi.org/10.1001/jamanetworkopen.2025.9198

Extended Summary

Central Research Question

The primary question of this research is whether living close to golf courses increases the likelihood of developing Parkinson’s disease. The study also asks whether groundwater conditions and water service systems contribute to the risk, given that pesticides commonly used on golf courses may contaminate local drinking water supplies. The research is designed to determine both the geographic relationship between residences and golf courses and the role of water systems as possible routes of exposure.

Previous Literature

Environmental factors are recognized as important in Parkinson’s disease alongside genetic influences. Previous studies have shown that pesticides such as paraquat, rotenone, and organophosphates can damage the nervous system by producing oxidative stress and impairing mitochondrial function. These biological mechanisms create a plausible link between environmental exposure and neurodegenerative conditions. Past epidemiological research has found associations between pesticide exposure and higher rates of Parkinson’s disease, but few studies have focused directly on golf courses as a potential source. Existing evidence suggested that pesticide application on U.S. golf courses is much higher than in Europe and that people living near or working on golf courses may be at increased risk. However, most of this evidence was anecdotal or based on small samples. This left a gap in the literature that called for a population-based study.

Data

The authors used the Rochester Epidemiology Project (REP), which links medical records across 27 counties in Minnesota and Wisconsin. The dataset covered the years 1991 to 2015. It included 419 newly diagnosed cases of Parkinson’s disease and 5,113 controls matched by age and sex. Demographic and socioeconomic data were added, including income levels and whether a residence was classified as urban, suburban, or rural. Geographic data on 139 golf courses were digitized using satellite imagery. Water service areas, groundwater vulnerability maps, and municipal well data were obtained from federal and state sources. Together, these data allowed the researchers to measure both physical distance to golf courses and environmental conditions that could influence pesticide exposure.

Methods

The study used a case-control design. Each Parkinson’s case was matched with 20 controls without the disease. Researchers measured the distance from residential addresses to the nearest golf course and grouped these distances into categories: less than 1 mile, 1–2 miles, 2–3 miles, 3–6 miles, and more than 6 miles. They also modeled distance as a continuous variable using piecewise linear splines to capture nonlinear effects. Logistic regression was applied to estimate adjusted odds ratios, controlling for age, sex, race, year of diagnosis, income, urban or rural location, and health care utilization. In addition, the authors examined whether living in water service areas with golf courses, in vulnerable groundwater regions, or with shallow municipal wells was associated with higher risk. Sensitivity analyses tested robustness by focusing on urban areas and restricting controls to the same county as cases.

Findings/Size Effects

The results showed that proximity to golf courses was significantly associated with higher odds of Parkinson’s disease. Individuals living within one mile of a golf course had 126 percent higher odds compared with those living more than six miles away (adjusted odds ratio [aOR] 2.26, 95% CI 1.09–4.70). Those living one to two miles away had nearly triple the odds (aOR 2.98, 95% CI 1.46–6.06). At distances of two to three miles, the odds were more than doubled (aOR 2.21, 95% CI 1.06–4.59). Even at three to six miles, the odds remained elevated at 1.92, though with wider confidence intervals. The pattern showed that risk generally decreased with greater distance beyond three miles, dropping by about 13 percent for every mile farther away.

The analysis of water systems reinforced these results. People living in groundwater service areas with golf courses had nearly double the odds of Parkinson’s disease compared to those in areas without golf courses (aOR 1.96, 95% CI 1.20–3.23). Compared with individuals relying on private wells, the risk was 49 percent higher (aOR 1.49, 95% CI 1.05–2.13). When groundwater vulnerability was factored in, people in vulnerable regions with golf courses faced 82 percent greater odds of Parkinson’s disease (aOR 1.82, 95% CI 1.09–3.03). In contrast, no significant associations were found with shallow municipal wells or wells located directly on golf courses, suggesting that contamination may occur through broader groundwater systems rather than isolated points.

Sensitivity tests confirmed the findings. Results were strongest in urban areas, raising the possibility that airborne pesticide exposure may also contribute. Overall, the study demonstrated consistent associations across multiple exposure measures.

Conclusion

This research provides evidence that living near golf courses is linked to an increased risk of Parkinson’s disease. The association was strongest within one to three miles and in areas where groundwater was vulnerable. The results are consistent with what is already known about pesticide exposure and neurodegenerative disease. The contribution of this study lies in its use of population-based data, precise geographic measurements, and integration of water system information.

While the study does not establish causation, its careful design and consistent findings give weight to the argument that pesticides used on golf courses may pose public health risks. The limitations include the case-control design, the absence of detailed occupational or genetic data, and the fact that golf course pesticide use was measured at only one point in time. Despite these limits, the study adds substantially to the literature by addressing an environmental exposure that has been understudied.

The implications for policy are significant. If further research confirms these findings, stronger regulations on pesticide use, better monitoring of groundwater in vulnerable areas, and public health education for communities near golf courses may be warranted. This study highlights how land use and environmental practices can have serious long-term effects on health. It suggests that preventing disease may require more attention to environmental exposures that extend beyond the immediate site of application.