Exposure to certain pollutants, such as nitrogen dioxide, would expose women to an increased risk of developing breast cancer.
Lhe links between pollution and breast cancer are confirmed. A study conducted on several thousand women in France shows that being exposed to certain air pollutants could increase the risk of breast cancer. Results that confirm other recent work on the subject. This study – known as Xenair and carried out by members of the Léon-Bérard center in Lyon, Gustave-Roussy, the Ecole Centrale de Lyon, the University of Leicester (United Kingdom), Ineris, the center Bordeaux Population Health – confirms, among other things, an increased risk of breast cancer in the event of exposure to nitrogen dioxide.
We already know very well the genetic or hormonal risk factors for breast cancer, the most common in women, and also those related to age or lifestyle (alcohol, physical activity, etc.). But, in recent years, several studies have also highlighted the role of certain pollutants. The authors of a meta-analysis published in 2021 pointed in particular to exposure to nitrogen dioxide, estimating that around 1,700 breast cancers each year in France could be linked to it. On the other hand, they considered the results on the risk linked to fine particles to be less conclusive.
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The authors of the Xenair study (funded by the ARC foundation) explored the association between the risk of breast cancer and chronic low-dose exposure to eight air pollutants: pollutants with xenoestrogenic properties – dioxins , BaP, PCB, cadmium – and pollutants to which exposure is daily – fine particles (PM10 and PM2.5), nitrogen dioxide (NO2), ozone (O3) –, according to a press release. Their work focused on 5,222 cases of breast cancer (diagnosed between 1990 and 2011), from a national cohort followed for 22 years, in comparison with the same number of unscathed cases. For each pollutant, average and cumulative exposures were estimated for each woman, taking particular account of places of residence.
An increase in the risk of breast cancer has, again, been measured in connection with exposure to nitrogen dioxide. These results should give rise to a forthcoming publication in the journal Environmental Pollution. A risk has also been highlighted with BaP and PCB153, two endocrine disruptors. The researchers also mention, this time, a risk linked to fine particles. But these results are not yet ready for publication. No association has been demonstrated for cadmium and dioxins, and analyzes are in progress for ozone.
If the exposure to pollutants of the women followed has decreased since 1990, except for ozone, the levels of exposure to nitrogen dioxide and particles remain well above health recommendations, observe the researchers. With exposure levels in line with the European thresholds for nitrogen dioxide (40 µg/m3), “1% of breast cancers in the Xenait population could have been prevented” and, with levels in line with the recommendations of the WHO (10 µg/m3), the figure reaches “nearly 9%”, according to the press release.
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