Living Near Dry Cleaners May Raise Parkinson's Disease Risk

For decades, the dry-cleaning solvent chemical trichloroethylene (TCE) has been linked with an elevated risk of Parkinson's disease. New evidence suggests the potential hazard may extend further than previously understood.

Dry cleaners and Parkinson's disease risk

A new study indicates that simply residing near a dry-cleaning business may be associated with a greater likelihood of developing the condition.

In a nationwide study published in npj Parkinson's Disease, researchers found that people living within 150 metres (0.15 km) of dry cleaners had an estimated Parkinson's risk up to 23 percent higher than those living 6.4–8 kilometres away.

"This study adds to growing evidence that environmental exposures may play an important role in Parkinson's disease," says Brad Racette, a neurologist at the Barrow Neurological Institute in Phoenix, Arizona, and the study's senior author.

"Identifying those exposures is an important step toward understanding how we might reduce the burden of this disease in the future."

These results contribute to an expanding body of research indicating that residential location can influence environmental exposures – and, in turn, possible health outcomes and disease risk.

People living within 150 metres of dry cleaners had up to a 23 percent higher risk of developing Parkinson's. (Romi Georgiadis/iStock/Getty Images Plus)

Previous research has shown that where a person lives is associated with dementia risk, and may influence the speed at which they age as well as how healthily they eat.

For Parkinson's disease, recognised environmental risk factors include air pollution, exposure to microplastics, and pesticides, among others.

Such factors mean that locations not outwardly considered dangerous can nevertheless pose unrecognised health risks because of their chemical environment.

For instance, research published last year reported that living close to a golf course was linked to greater Parkinson's risk, probably because pesticides are used on its fairways and greens.

Living near a golf course may also raise the risk of Parkinson's disease. (Somchai Sookkasem/Getty Images)

What the nationwide analysis found

Several researchers behind that finding have now investigated dry cleaners. Using US Medicare records from 2016 to 2018, they examined more than 19 million people aged 67 or over, including approximately 180,000 individuals diagnosed with Parkinson's disease.

Having adjusted for age, sex, race, income and other possible confounding influences, the team estimated that people living within around 150 metres of a dry cleaner had a 14 percent higher overall Parkinson's risk than people residing 6.4–8 kilometres away.

The estimated risk was 23 percent higher for Parkinson's disease cases characterised by walking and mobility difficulties. It reached 25 percent higher for dementia-associated Parkinson's, although this subgroup had a weaker overall relationship with distance.

The results demonstrate an association only: they do not establish that dry cleaners or dry-cleaning substances such as TCE cause Parkinson's disease. Even so, they raise concerns.

"Our county-level association map revealed a broadly consistent pattern across much of the US linking residential proximity to dry cleaners with Parkinson's disease risk," the researchers write in their paper.

"These spatial patterns suggest that some regions may be particularly vulnerable to environmental contamination from dry cleaners, potentially reflecting differences in vapor intrusion risk related to aging infrastructure, geology, or population density."

Related: Dry Cleaning Chemical Could Be Major Cause of Parkinson's, Scientists Warn

Limits of the dry-cleaner data

The researchers note several study limitations. In particular, their measure of dry-cleaning exposure used 2013 location data for more than 30,000 dry-cleaning businesses, which cannot accurately account for relevant details such as quantities of TCE and other chemicals, building features, or business activity patterns.

Nevertheless, given what is already known about the scale of the problem, the team says the results add further evidence of a serious concern.

"Our findings suggest that chemicals used in dry cleaning may contaminate nearby neighborhoods and contribute to Parkinson's disease risk," the researchers write.

"Our study provides evidence supporting the need for targeted disease surveillance and further environmental investigation for possible remediation."

The findings appear in npj Parkinson's Disease.

This article was fact-checked and edited by Rebecca Dyer. Although we take pride in our process, we are only human. If you notice an error, please tell us.