Living Near Dry Cleaners May Raise Parkinson's Disease Risk

Dry cleaners and Parkinson's disease risk

Trichloroethylene (TCE), a chemical solvent used in dry cleaning, has been linked with an increased risk of Parkinson's disease for decades. New evidence suggests the potential threat could be wider than previously understood.

Fresh research indicates that simply residing near a dry-cleaning business may increase the likelihood of developing the condition.

In a nationwide study published in npj Parkinson's Disease, researchers found that people living within 150 metres 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."

The results join a growing body of work showing that a person's location can influence their environmental exposures – and, potentially, their health 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)

Earlier studies have shown that where someone lives is associated with dementia risk, and may also influence the rate at which they age and how healthily they eat.

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

Such risk factors mean that environments which do not appear overtly dangerous can nonetheless present unrecognised health hazards because of their chemical conditions.

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

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

What the dry-cleaner study found

Some of the scientists behind that finding have now examined dry cleaners. They assessed US Medicare records from 2016 to 2018 for more than 19 million people aged 67 or above, including roughly 180,000 people with a Parkinson's disease diagnosis.

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

The estimated risk was 23 percent higher for cases of Parkinson's disease characterised by difficulties with gait and mobility. It reached 25 percent higher for Parkinson's associated with dementia, although the connection between this subgroup and distance was weaker overall.

The results demonstrate only an association, rather than proving that dry cleaners or dry-cleaning chemicals 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

Limitations and environmental contamination

The researchers note several limitations. In particular, their measure of dry-cleaning exposure relied on 2013 location data for more than 30,000 dry-cleaning businesses, which does not accurately account for relevant details including quantities of TCE or other chemicals, building features, or business-activity patterns.

Nevertheless, given what is already known about the scale of the problem, the researchers say the study offers further evidence of a highly serious issue.

"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 are published 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.