Gut Microbes, Genes, and the Environment Shape Parkinson’s Disease

Parkinson’s disease is a neurodegenerative disorder that affects approximately 10 million people worldwide. Currently, patients can at best hope for therapies that slow disease progression and alleviate symptoms.

Scientists have long suspected that communication between the gut and the brain may contribute to the development of Parkinson’s disease. Recently, a new study identified specific gut microbes that appear to play a role in the disease and linked them to reduced levels of riboflavin (vitamin B2) and biotin (vitamin B7).

The Parkinson’s Foundation has also pointed to environmental factors, noting that exposure to toxic substances and agricultural pesticides may be associated with an increased risk of developing Parkinson’s disease. Researchers continue to work toward a better understanding of the wide range of environmental exposures linked to Parkinson’s disease (PD).

Most experts agree that PD results from a complex interaction between genetic and environmental factors, including exposure to chemicals, toxins, and head trauma.

These interactions can be difficult to unravel: some environmental exposures may lower the risk of PD, while others may increase it. Likewise, certain genetic profiles may make individuals more vulnerable to the effects of toxic substances. Researchers believe that a combination of these factors can trigger biological changes that ultimately lead to Parkinson’s disease.

Environmental Risk Factors

Head Injury: Traumatic brain injury—defined as an injury that alters the level of consciousness—has been associated with an increased risk of developing PD years later, although the underlying mechanisms remain unclear.

Area of Residence:Geographic differences in PD prevalence have been observed. These variations may reflect differences in environmental exposures as well as genetic risk factors.

Occupation:Certain occupations or job categories have been linked to a higher incidence of PD, though findings across studies have been inconsistent.

Exposure to Metals:Occupational exposure to various metals has been suggested as a potential risk factor for PD. However, long-term exposure is difficult to measure, and study results linking specific metals to PD risk have been mixed.

Solvents and Polychlorinated Biphenyls (PCBs):Trichloroethylene (TCE), a solvent widely used in industry and a common groundwater contaminant, has been associated with PD among workers with long-term occupational exposure. PCBs have been found at relatively high concentrations in the brains of individuals with PD. Occupational exposure to PCBs has been linked to an increased risk of Parkinson’s disease in women, but not in men.

For more information, visit the Parkinson’s Foundation website:

https://www.parkinson.org/understanding-parkinsons/causes/environmental-factors