Long-term air pollution exposure and breast cancer

Abstract

Background: Women in urban communities of Iran have the highest incidence rates of breast cancer (BC). The reasons behind this are not fully understood and many of the causes remain unexplained. Aims: The aim of this study was to examine the relationship between exposure of BC cases and exposure of the general population to long-term air pollutants in the Middle Eastern City of Tehran, Iran. Methods: Records of 1534 BC patients were obtained from Non Communicable Disease Center belong to Ministry of Health (with disease onset during 2008 to 2009). Thereafter, they were successfully geo-coded within Tehran megacity by Geographic Information System (GIS) Bureau of Iran’s Post Office based on their postal code. On the other hand, 3008 random cases were created within the city by a GIS. The individual long-term exposure to sulfur dioxide (SO2) and particulate matter ? 10 µm (PM10) air pollutants of all BC and random cases were estimated using land use regression models. Finally, bivariate correlations of the exposure of these groups were calculated. Results: The annual mean concentration of SO2 and PM10 in the BC cases were 62.9 parts per billion (ppb), and 97.6 µg/m3, respectively. While in our random points the mean exposures for mentioned pollutants were 54.1 ppb, and 93 µg/m3, respectively. The correlation of long-term exposure to SO2 between BC and random cases was positive and significant (r = 0.06, p = 0.019). Meanwhile, the correlation of long-term exposure to PM10 between BC and random cases was positive and significant (r = 0.05, p = 0.037). Conclusions: We have found that long-term air pollution exposure is associated with breast cancer.