Breast cancer incidence and the air pollution level in the communes of Chile: an ecological study

There is evidence linking air pollutants associated with vehicular traffic such as polycyclic aromatic hydrocarbons with breast carcinogenesis. Epidemiological studies have shown conflicting results regarding air pollution and breast cancer risk, which could be explained by the multitude of other risk factors that could affect the association. In Chile, air pollution has reached alarming levels, either due to motorised vehicle traffic or the combustion of wood for heating; therefore, our objective was to evaluate the association between the incidence of breast cancer and the concentration of the main air pollutants monitored in the country. We carried out a cross-sectional ecological study that evaluated the association between the average incidence of breast cancer in years (2016 to 2018) and the average annual concentration of six atmospheric pollutants in the 5 years prior to the estimation of the rate in communes of Chile, using the population of beneficiaries of Instituto Oncologico Fundacion Arturo Lopez Perez. The annual incidence of breast cancer was 72.21 cases per 100,000 women and it varied significantly in the communes studied compared to the human development index (HDI) and to the proportion of women in the age group at highest risk. Assessing the relationship between the incidence of breast cancer and the average concentration of atmospheric pollutants, we only found a direct correlation between the level of nitrogen dioxide and the rate (R = 0.82; p = 0.044), whose significance tends to be lost when age and the communal HDI are included in a regression model.