npj Parkinson’s Disease: Living Near Dry Cleaners Linked to Higher Risk of Parkinson’s Disease

Living near dry-cleaning facilities may be associated with a higher risk of developing Parkinson’s disease in older adults, according to a study by US researchers. The study has been accepted for publication in the journal npj Parkinson’s Disease.

The researchers analyzed medical data from nearly 19 million Medicare beneficiaries aged 67 and older. Among them, 180,982 cases of Parkinson’s disease were identified. The scientists compared participants’ residential locations with the locations of 32,723 dry-cleaning facilities across the United States.

The results showed a clear association between distance from a dry cleaner and the likelihood of developing the disease. People who lived within 150 meters of a dry-cleaning facility had a 14% higher likelihood of developing Parkinson’s disease than those who lived 1.2 to 8 kilometers away.

The association remained as the distance increased, although it gradually weakened. It was strongest among patients with gait disturbances: those living very close to dry cleaners had a 23% higher likelihood of developing Parkinson’s disease accompanied by these symptoms. For cases involving dementia or cognitive decline, the increase was 25%, while for patients with a history of falls, it was 19%.

However, the researchers found no statistically significant association among patients whose medical records listed tremor. They noted that this symptom may not have been adequately documented in medical records.

The researchers suggest that the findings may be related to exposure to chemical solvents historically used in dry cleaning. In particular, they point to trichloroethylene (TCE) and tetrachloroethylene (PCE), substances with neurotoxic properties that can persist in the environment for extended periods.

However, the scientists emphasize that the study does not establish a causal relationship between living near a dry cleaner and developing Parkinson’s disease. Distance from a facility was used only as an indirect measure of potential solvent exposure; the researchers did not measure participants’ individual exposure levels.

In addition, some facilities may have served only as clothing drop-off points and may not have used solvents on site. The researchers also cannot rule out the influence of other environmental factors or characteristics of the neighborhoods where participants lived.

The authors say the findings highlight the need for further research into the potential effects of chemical solvent exposure on the risk of developing Parkinson’s disease.

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