Air pollution tied to breast cancer risk

A more polluted air appears to increase the likelihood of developing breast cancer, a recent South Korea study has shown.

Researchers conducted a nationwide, whole-population census study, including the 252 administrative districts of South Korea. Exposure variables were indicators of air pollution, such as nitrogen dioxide (NO₂), carbon monoxide (CO), sulfate dioxide (SO₂) and 10-µm particulate matter (PM₁₀). At the time of data collection, the South Korean female population was 24,149,865.

Multivariable linear regression modeling, adjusted for altitude, higher education, smoking rate, obesity and gross regional domestic product per capita, showed that air pollutants were directly correlated with breast cancer risk. Every 100-ppb increase in CO, for example, significantly increased the likelihood of the malignancy (odds ratio [OR], 1.08, 95 percent confidence interval [CI], 1.06–1.10).

In absolute terms, this meant that women living in districts with air CO concentrations higher by 100 ppb were 8 percent more likely to develop breast cancer.

NO₂ (OR per 10 ppb, 1.14, 95 percent CI, 1.12–1.16), SO₂ (OR per 1 ppb, 1.04, 95 percent CI, 1.02–1.05) and PM₁₀ (OR per 10 µg/m³, 1.13, 95 percent CI, 1.09–1.17) also emerged as significant risk factors. Of these, only PM₁₀ independently predicted breast cancer mortality (OR, 1.05, 95 percent CI, 1.01–1.09).

Multi-pollutant models confirmed these findings. All of the four air pollutants examined remained significantly associated with the risk of breast cancer even when additionally adjusted for the other three pollutants.