Pesticide exposure can increase the risk of Parkinson’s disease in individuals

Parkinson’s disease (PD) is a common degenerative condition of Brain. It commonly affects the elderly, although no age is exempt. PD is a growing epidemic due to ageing population across the globe. The primary change noted in PD patients is the progressive loss of dopamine producing cells in a specific area of Brain called Substantia nigra. What triggers this cell loss? and why only certain individuals are affected? These questions remain unanswered at present. It is proposed that a combination of genetic and environmental factors play a role.

Parkinson’s is a slowly developing condition and the cell loss in brain often starts several years prior to the onset of symptoms. It is difficult to ascertain the causal factors present in the nature over such a long period; often several factors can come together to produce the disease. We understand about these environmental culprits through retrospective and observational studies, which are often prone to bias. However, these studies have consistently shown that certain factors like smoking and coffee are protective, while others such as pesticide exposure increases the risk of developing PD.

The role of pesticides is important in an agrarian country like India. Although the risk is high among farmers who are constantly exposed to these pesticides, an increased risk was noted even with household exposure such as gardening or using insecticides (eg: rat killers). Interestingly, some studies have highlighted an increasing risk of PD with consumption of well water in rural areas, possibly due to contamination with pesticides. Among the pesticides, herbicides and insecticides like paraquat carry a higher risk compared to fungicides. Scientists are using innovative methods like Geographic Information System and satellite remote sensing data to calculate pesticide exposure and the risk of PD.

A latest study has analyzed the data of 21.5 million people enrolled with medicare and noted a consistent relationship with 14 of the 65 studied pesticides. Among these herbicides like simazine, atrazine and organochlorides like lindane carried the highest risk.

Pesticide exposure is also implicated in other brain disorders like Alzheimer’s dementia, motor neuron disease, childhood developmental delay among others. In recent times, non-profit organization like Michael J Fox foundation is actively engaged with the government to ban certain pesticides like Paraquat.

Dr. Mirza Masoom Abbas, Consultant – Neurologist, Manipal Hospital Yeshwanthpur and Millers Road