Air pollutants are risk factors for lung cancer as well as breast cancer, as a summary of the international literature shows. Of the three main pollutants examined, nitrogen dioxide wins the award with the highest evidence: around 1,700 breast cases. It is believed that cancer, or 3%, each year in France is due to this exposure and to particulate matter pollution.
Certain air pollutants, particularly airborne particles and air pollution in general, are recognized as carcinogenic by the IARC (International Agency for Research on Cancer); This recognition is related to its proven effects on lung cancer.
In recent years, however, epidemiological studies have shown that air pollutants could also influence the development of breast cancer, the most common cancer in Europe.
Risk factors are the most well-known factors that contribute to fertility (e.g. age at menarche), alcohol consumption, and environmental factors of likely exposure, especially those that alter the estrogen axis, and genetic polymorphisms related to BRCA genes. In this study, carried out by the team of Inserm research director Rémy Slama at the Institute for the Promotion of Biosciences (IAB, Inserm / CNRS / UniversitéGrenoble Alpes), scientists were interested in the role of certain air pollutants in the occurrence of breast cancer. The aim was to synthesize the results on the dose-response relationship between contamination and the appearance of breasts. t Cancer, taken from all available publications – a so-called meta-analysis that provides an average of the relationships described by each study, taking into account their accuracy, wanted an estimate of the number of breast cancer cases that can be attributed to it in France and an estimate of the associated ones economic costs. Researchers have found a link between nitrogen dioxide (NO2) and the occurrence of cancer.
Breast cancer in studies in women in North America and Europe. © Unsplash In studies on women in North America and Europe, researchers have identified a link between nitrogen dioxide (NO2) and the development of breast cancer. © UnsplashThe harmful effects of nitrogen dioxide has been proven The study, the results of which were published in the journal Environmental Health Perspectives, made it possible to identify the three pollutants considered, namely suspended particles with a diameter of less than 10 micrometers (PM10), suspended particles with a diameter of less than 2.5 micrometers (PM2.5) and nitrogen dioxide (NO 2), 27, 32 and 36 associations, respectively, with breast cancer incidence, all of which have been reported in women in North America and Europe. In the case of nitrogen dioxide, the synthesis of the studies speaks most clearly for an adverse effect on the development of breast cancer. Nitrogen dioxide is mainly emitted when fossil fuels are burned, for example by internal combustion engines.
The estimated effect of nitrogen dioxide was greatest in hormone-dependent breast cancers (whose tumors express estrogen and progesterone receptors). Although not all studies have been able to take this criterion into account, the researchers estimate that around 1,700 cases of breast cancer, or around 3% of the cases occurring annually in France, could be attributed to this exposure and other nitrogen dioxide-related pollutants.
The material costs (associated with treatment) and immaterial costs (associated with death, loss of quality of life and suffering of the patient) are of the order of 600 million to one billion euros per year 1,700 cases of breast cancer, about 3% of the cases that occur annually in France could be attributed to this nitrogen dioxide exposureFor the other two pollutants considered (PM10 and PM2.5), the evidence was lower, although a harmful effect could not be ruled out. “Carrying out such a large meta-analysis is an approach that has the advantage of synthesizing the entire scientific literature on this topic and therefore obtaining particularly reliable results. In this case, the analysis for nitrogen dioxide focused on a series of 36 studies that add up to more than 120,000 cases in 3.9 million subjects, ”emphasizes Rémy Slama. it is the most common type of cancer in Europe. Polycyclic aromatic hydrocarbons (PAH), which are also found in food, are also added to the nitrogen oxides. © freshidea, Adobe Stock Breast cancer is the most common cancer in Europe. ), which are also found in food, are also added to nitrogen oxides.© freshidea, Adobe Stock The observation approaches used in this work do not exclude the contribution of other pollutants whose atmospheric concentrations correlate closely with those of nitrogen dioxide. or estrogen-disrupting activity, such as polycyclic aromatic hydrocarbons (PAHs).