Living near dry cleaners linked to increased risk of Parkinson's disease
Nearly 19 million Americans were included in a study that found a distance-dependent link between living near a dry cleaning business and Parkinson's disease. Among those living within about 152 meters, higher odds for the disease were found. Dr. Sandra Benizri, a neurologist at Assuta: "There is no doubt that environmental factors play a role in Parkinson's. In recent years, there has been a dramatic increase in the number of cases, which is likely related to environmental changes and various types of pollution."
For most of us, a dry cleaner is just a convenient neighborhood service. We drop off clothes, pick them up clean, and move on. However, a large-scale American study raises a troubling possibility: living near a dry cleaner may be associated with higher odds of developing Parkinson's disease.
The study, published in the journal npj Parkinson's Disease, was based on Medicare data for nearly 19 million Americans aged 67 and older. The researchers identified 180,982 people who were first diagnosed with Parkinson's between 2016 and 2018, and compared them to 18,848,268 people who were not diagnosed with the disease. The main finding was a distance-dependent link: the closer participants lived to a dry cleaner, the higher the odds of a Parkinson's diagnosis. Among those who lived within about 0.15 kilometers of a dry cleaner, the odds for the disease were 14% higher compared to those who lived 6.4 to eight kilometers away.
The researchers took into account factors that might affect the results, including age, sex, race, smoking probability, income in the area of residence, use of health services, degree of urbanization, and PM2.5 air pollution. The link was found among both men and women, but was stronger and persisted at greater distances in men.
The link between Parkinson's and environmental factors
Dr. Sandra Benizri, a specialist neurologist at Assuta Medical Centers, explains that the findings add to the accumulated knowledge about the impact of the environment:
"There is no doubt that environmental factors play a role in Parkinson's. In recent years, there has been a dramatic increase in the number of cases, which is likely related to environmental changes and various types of pollution, including air pollution. There is also strong evidence that pesticides increase the risk of Parkinson's, and that people living near agricultural areas are at higher risk. The current study adds another possible environmental factor to the picture."
In recent years, several studies have been published that examined the link between environmental factors, lifestyle, and Parkinson's. For example, a study conducted at the University of California found that prolonged exposure to the pesticide chlorpyrifos was linked to a risk of the disease more than 2.5 times higher. A Danish study that included more than three million people found that prolonged exposure to traffic noise was linked to a small increase in risk.
A different picture between regions
The strongest link was found among people who were diagnosed with Parkinson's and who had documented problems with walking and movement even before the diagnosis. Among those who lived within about 152 meters of a dry cleaner, the odds for a Parkinson's diagnosis were 23% higher. At the same distance, 25% higher odds were found among people with dementia or a decline in memory and thinking, and 19% higher odds among those who suffered from falls.
Dr. Benizri explains that Parkinson's disease does not manifest identically in all patients:
"In some cases, tremor is the main symptom, but in about 30% of cases, there is no tremor at all. Postural disorders usually appear at a later stage of the disease, but there are patients who develop them at a relatively early stage. According to the study, it is possible that the strongest link to living near a dry cleaning business is found precisely among people with postural disorders."
The strength of the link varied between different regions in the United States. In southern Illinois, the odds for Parkinson's among those who lived near a dry cleaner were 150% higher compared to those who lived further away. The researchers believe that the differences between the regions may be related to old pollution, infrastructure, soil type, or population density.
Two suspected chemical substances
The main suspicion concerns two chemical substances that have been used for years in dry cleaning: TCE and PCE. These substances help dissolve grease and remove stains from clothes without using water. TCE (trichloroethylene) is known as a carcinogen that causes kidney cancer. Over the years, many dry cleaners have switched to using PCE, but this substance can decompose into TCE under the ground.
Both substances can remain in the soil and groundwater for years, even after the dry cleaner has closed. They can also evaporate, penetrate through the soil, and reach nearby buildings. In 2024, the US Environmental Protection Agency imposed a nationwide ban on the use of TCE. The use of PCE is supposed to be phased out over ten years.
The study does not point to a danger resulting from wearing the clothes after cleaning. The concern relates mainly to inhaling the substances, direct contact with them, and the pollution they may leave in the soil, water, and air.
Dr. Benizri emphasizes: "The findings should be interpreted with caution. Further studies are needed to establish the link and better understand its meaning."
