Air pollution is causing epigenetic changes in Bogotá residents

The extremely high air pollution in some areas of Bogotá is changing the respiratory system of residents of the Colombian capital. The permanent exposure to small harmful particles suffered by the inhabitants of localities such as Kennedy or Tunjuelito has caused significant alterations to their DNA, changes that increase the risk of suffering from respiratory diseases. These are two of the main findings of a study carried out by the Institute of Human Genetics of the Faculty of Medicine of the Pontifical Javierian University, in alliance with the San Ignacio University Hospital, the National University and the Francisco José de Caldas District University.

The research determined that healthy people who live or work in places with the highest levels of pollution, such as the Carvajal-Sevillana area, located between the Autopista Sur and Avenida Boyacá, have epigenetic changes very similar to those seen in a person diagnosed with severe asthma. Epigenetics is the study of the relationship between the environment and the expression of human DNA, and includes factors such as diet, exercise, medication use, and exposure to chemicals.

Professor Adriana Rojas Moreno, from the Javeriana Institute of Human Genetics and one of the leaders of the work, explains that these changes are not in the DNA sequence, but in the way it functions and how it is expressed. “We analyzed whether a gene behaves differently due to permanent exposure to air pollution,” Rojas tells EL PAÍS. “We concluded that particulate matter and environmental pollution are definitely generating epigenetic changes, which in the long term can lead to an exacerbated allergic response and consequently problems such as acute rhinitis, diseases such as COPD [Chronic Inflammatory Pulmonary Disease], or asthma.”

Rojas Moreno says that a few years ago she and her research group decided to evaluate whether severe pollution peaks in Bogotá were affecting people's health. "We have done work with electronic cigarettes and with conventional cigarettes. Now we decided to concentrate on the effects of poor air quality, which affects us all to varying degrees. Cigarette consumption is a personal decision, while exposure to environmental pollution is neither voluntary nor can it be controlled or stopped."

To determine these potential health risks, the researchers first analyzed the places in Bogotá with the highest levels of air pollution. This work was carried out by the engineering group at Distrital University, which used data from air monitoring stations over the past five years. At the end of this first phase, they found that during times of high traffic flow, parts of the neighborhoods of Tunjuelito and Kennedy, and the Carvajal-Sevillana area, exceeded the maximum pollution levels established by the World Health Organization (WHO) by up to 10 times.

Daniel Mauricio González, a bacteriologist who studied at the Javeriana Institute of Human Genetics, explains that the WHO establishes a limit of 15 micrograms of fine particulate matter per cubic meter of air, and that in the areas of Bogotá most affected by pollution, this level reached 150. “Bogotá is one of the most polluted cities in Colombia, and Colombia is the ninth most polluted country in the entire region,” says González, who is doing his doctorate in the study of epigenetic changes associated with exposure to particulate matter.

The WHO has said that particulate matter pollution is the main environmental risk to public health. It causes seven million deaths a year globally, 80% of which are in developing countries like Colombia. “There is a problem with pollution, and it is that, even if we are in an enclosed space, we breathe the small polluting particles that are in the air. In addition to nitrogen, oxygen and all the chemical components of the atmosphere, we inhale the particulate matter that is produced mainly by the combustion of gasoline or diesel,” says González. “The particles are so small that they settle deep in our lungs, and over time they alter their functioning.”

The second phase of the research was to go to the most polluted areas and look for healthy people, with no pathologies or respiratory disease. The participants selected had to have lived in one of the polluted areas for at least five years and that spent more than eight hours a day there. The researchers conducted interviews, surveys, took blood samples and performed molecular analyses to assess whether there were epigenetic changes in the participants. They did the same with healthy people from localities such as Usaquén and Barrios Unidos, which have the best air quality indexes in Bogotá.

Finally, they compared the samples with a group of people who suffer from severe asthma. The result was overwhelming and surprising. “I knew that people with more exposure to polluted air would have changes in the respiratory system, but I never imagined that they would be so similar to those of patients with severe asthma,” says Professor Rojas.

Despite the similarities in the expression of the genes of healthy people exposed to pollution and people with asthma, there are still no studies that can predict with certainty how long it will take for the disease to develop in people exposed to pollution. “There are few studies in the world similar to the one we did. There are some, in Germany, with exposure to diesel, but there are no conclusive findings that support or demonstrate what the minimum time of exposure to pollution is for a person to begin to develop respiratory symptoms. The same is true of electronic cigarettes; there is still no evidence of how long you have to vape to develop cancer,” says Rojas. “Whether or not the disease develops depends on many other factors, but with these changes in the genome, the risk increases,” adds González.

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