Scientists have linked living near a hotbed of water pollution to a rare brain disease

Environmental pollution may be one of the factors associated with the development of neurodegenerative diseases. Scientists have found that people living near industrial facilities that pollute water are more likely to experience a rare movement disorder — progressive supranuclear palsy. At the same time, the researchers emphasize that the data obtained does not prove a direct cause-and-effect relationship. The information about which pollutants the scientists studied and what they found out is in the Izvestia article.

Near industrial facilities

A study published in the journal Neurology focuses on a possible link between living near businesses that pollute water and the development of progressive supranuclear palsy (PNP). This is a rare neurodegenerative disease that affects movement and leads to an increase in disorders over time.

Scientists have observed more than 500,000 UK residents over a period of up to 25 years. During this time, 221 participants were diagnosed with PNP. For comparison, the researchers selected people of the same age and gender who did not develop the disease: 10 participants in the control group accounted for each case.

The experts then compared the home addresses of the participants, recorded in 2007, with the location of industrial facilities that reported emissions of pollutants into the water. The study took into account six categories of compounds: heavy metals, chlorinated solvents, persistent organic pollutants, pesticides, and other organic and other inorganic pollutants. People who had lived at the specified address for less than a year were not included in the analysis.

About a third of the participants, who were subsequently diagnosed with PNP, lived at a distance of about 4.8 km from an industrial facility associated with water pollution. In the control group, the proportion of such people was about a quarter. However, proximity to an enterprise does not in itself mean that a person has been exposed to a specific substance in a dangerous concentration.

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Which substances have attracted the attention of scientists

The researchers found the most noticeable differences for four categories of pollutants. After age, gender, and education level were taken into account, living near facilities that emit pesticides was associated with a 66% increase in the relative risk of PNP. The indicator was 60% for inorganic pollutants, 52% for other organic compounds, and 38% for heavy metals.

Differences were also observed in the proportions of participants who lived near such facilities. 16% of participants with PNP and 11% of people from the control group lived near enterprises associated with pesticide emissions. For inorganic pollutants, the figures were 38% and 28%, respectively. 36% of the participants with the disease lived near objects that emit other organic compounds, compared to 28% in the control group. For heavy metals, the ratio was 38 and 31%.

At the same time, no association with PNP was found for the other two categories studied — chlorinated solvents and persistent organic pollutants. These percentages of increased risk are relative indicators, not the likelihood of getting sick for a particular person. The disease itself remains rare, including among people living near industrial facilities.

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What is known about the disease

Progressive supranuclear palsy belongs to a group of neurodegenerative diseases known as atypical Parkinsonism. It can be accompanied by disturbances in balance, walking, and eye movements. Some symptoms resemble those of Parkinson's disease, but PNP usually progresses faster and responds differently to treatment.

The causes of the disease have not been fully established. Therefore, scientists are studying various possible risk factors, including environmental factors. The new work complements these studies by looking not at direct measurements of the effects of pollutants on the body, but at the distance between the participants' place of residence and the industrial facilities that reported emissions.

Therefore, the results do not allow us to assert that a single pesticide or heavy metal causes PNP. They point to a possible link between environmental conditions and the likelihood of diagnosis, which needs to be checked in further studies.

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Why more research is needed

The scientists also found signs that the link between the risk of PNP and proximity to industrial facilities weakened as the distance increased — the analysis took into account the distance to about 9.7 km. In addition, the length of stay near polluting enterprises could make a difference. However, these observations do not allow us to establish an exact safe distance or determine how long it takes for the disease to develop.

There are other limitations to the job. The researchers did not have complete information about the participants' work history, so they could not assess the possible effects of pollutants in the workplace. In addition, many enterprises emitted several types of substances at once, which made it difficult to separate the effects of each pollutant.

The researcher emphasized that the overall probability of developing PNP remains low regardless of where a person lives. The authors consider it necessary to continue studying possible risk factors before drawing more definite conclusions about the role of water pollution in the development of the disease.