Dementia: pollution is related to high risk of the disease – 04/28/2023 – Equilíbrio

Fine particles of pollution dispersed in the air increase the chances of developing some type of dementia throughout life. That was the discovery made by Harvard researchers, who read more than a thousand scientific works on the subject. Neurodegeneration adds to many other consequences of environmental degradation.

According to the scientists themselves, more than 57 million people in the world live with diseases that affect cognitive capacity, such as Alzheimer’s or Parkinson’s. Interested in understanding how air pollution can affect brain development, experts surveyed the main scientific databases available.

They found 1092 original studies that met previously established quality criteria: 18 years as the minimum age of participants, follow-up over time, use of official air quality parameters in the United States, and survey of reports of dementia among volunteers. After filtering the materials, they reached 16 most relevant scientific publications.

Very fine particles, less than 0.0025 millimeters in diameter, called PM2.5, are the most dangerous pollutant found. In the USA, the legislation establishes a minimum concentration of 12 micrograms per cubic meter, but studies have found even lower concentrations, of 2 micrograms. They were enough to increase cases of dementia. In Brazil, the legislation establishes 25 micrograms as the minimum daily level.

Admir Targino, a professor at UTFPR (Federal Technological University of Paraná), states that the main sources of material emissions in cities are car exhausts, the burning of organic material and the resuspension of dust. But it’s not just urban dwellers who are subject to this problem. In the field, the fires also throw large amounts of material into the air. The specialist adds that, once in the atmosphere, there is no minimum safe limit for substances that are not natural.

Other pollutants analyzed by the scientists were nitrogen oxides and ozone. The latter showed no clear correlation with loss of cognition. The results were published earlier this month in the scientific journal The BMJ. Targino points out that there is also a growing concern about the toxicity of minor compounds, such as dioxins, furans and black carbon, also known as soot, which cause harmful effects on health.

Among the aspects investigated by the scientists are the biological mechanisms by which pollution affects the human body, but the researchers conclude that they are still not completely understood. One of the main suspicions of experts is that pollutants cause cardiovascular problems, which can lead to dementia.

In another survey, published in the same scientific journal, European researchers analyzed data from more than 300,000 people gathered in eight groups from different countries and showed that an increase of 5 units of concentration of the same particulate matter is associated with 13% more deaths from natural causes, even to the extent permitted by law.

Professor and researcher at UFPE (Federal University of Pernambuco), Helotonio Carvalho says that in addition to milder symptoms, such as nose and throat irritation, nausea and headache, it is now known that pollution is associated with asthma, bronchitis, heart attack , pulmonary emphysema, stroke, cancer (mainly lung), and newly discovered diseases such as autism and reduced fertility, as well as low IQ among newborns. “Over the years, that list has unfortunately grown,” he says.

The research authors point out that, despite the correlation, the effects of air pollution are smaller than other risk factors associated with the disease, such as schooling and smoking. It is estimated that up to 40% of cases of dementia worldwide can be avoided with changes in habits and preventive measures. Even so, they argue, the size of the world’s population that is exposed to air pollutants justifies taking public health measures to reduce this aggravating factor.