The regions studied included parts of Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, South Dakota, Texas, Utah, and Wyoming. People living in counties with the highest use of these three pesticides ran a 25-36% greater risk of Parkinson’s than those with the lowest use (broken down, the risk was 36% higher for simazine, 25% for lindane, and 31% for atrazine).
