Proximity to Golf Courses and Risk of Parkinson Disease

This study found that people living near golf courses were more likely to be diagnosed with Parkinson's disease, with the strongest link seen among those drinking water from groundwater sources shared with a golf course in regions where water contamination spreads easily. However, several design issues prevent firm conclusions about whether golf courses are actually the cause.

• Urban vs. rural imbalance: Parkinson's patients were overwhelmingly from cities (80%), while control participants were mostly suburban or rural (69%) — golf courses are also mostly in cities, so the association may partly reflect urban living rather than golf course pesticides
• Missing controls: 39% of control participants were excluded for incomplete address records vs. only 7% of patients — those excluded were more likely rural and far from golf courses, artificially making the remaining controls look more 'nearby' than they really should be
• No comorbidity adjustment: conditions that co-vary with urbanicity (e.g., hypertension, metabolic syndrome) and may cluster near golf-course-adjacent neighbourhoods are entirely uncontrolled, compounding the urbanicity confounding concern
• The headline result is statistically fragile: the main finding — that living within 1 mile of a golf course more than doubles PD odds — has a p-value of 0.03, which does not hold up when correcting for the number of comparisons made; the more robust water-contamination finding (p=.001) is a secondary result the authors themselves do not lead with
• No actual pesticide measurements: proximity to a golf course is used as a stand-in for pesticide exposure, but no pesticide levels were measured in water, soil, or participants
• Observational design: association studies of this kind cannot establish that golf courses cause Parkinson's disease — only that the two co-occur geographically