Long-term air pollution exposure increases breast cancer risk by 28%
New research has linked long-term exposure to fine particle air pollution, whether at home or work, to an increased risk of breast cancer. The findings add to the mounting evidence about the dangers of air pollution and highlight the need to reduce it.
Breast cancer has become the most commonly diagnosed cancer worldwide. Its risk factors are well-known and include age, obesity, harmful use of alcohol, smoking, and a family history of breast cancer.
Now, a new study has added another risk factor: fine particle air pollution. In a paper being presented at the upcoming European Society for Medical Oncology (ESMO) Congress 2023 in Madrid, Spain, researchers examined the link between long-term exposure to fine particle air pollution and breast cancer risk.
“Our data showed a statistically significant association between long-term exposure to fine particle air pollution, at home or at work, and risk of breast cancer,” said Béatrice Fervers, the lead author of the study. “This contrasts with previous research which looked only at fine particle exposure where women were living, and showed small or no effects on breast cancer risk.”
Fine particulate matter, or PM2.5, is tiny particles or droplets in the air that are 2.5 microns or less in diameter. Emissions from combustion of gasoline, oil, diesel fuel or wood produce much of the PM2.5 found in outdoor air. Indoor activities can also generate PM2.5, including pets, mold, cleaning products, smoking tobacco and burning wood and candles. Larger particles, 10 microns or less, are called PM10.
The researchers compared home and workplace exposure to pollution in 2,419 women with breast cancer and 2,984 women without breast cancer from 1990 to 2011. They found that breast cancer risk increased by 28% when exposure to PM2.5 increased by 10 µg/m3, approximately equivalent to the difference in PM2.5 concentration typically seen in rural versus urban areas of Europe. Women exposed to high levels of PM10 or nitrogen dioxide, another air pollutant, showed a smaller increase in breast cancer risk.
“These very small particles can penetrate deep into the lung and get into the bloodstream from where they are absorbed into breast and other tissues,” said Charles Swanton from the Francis Crick Institute, London, who presented research suggesting how PM2.5 may trigger lung cancer in non-smokers at last year’s ESMO Congress. “There is already evidence that air pollutants can change the architecture of the breast. It will be important to test if pollutants allow cells in breast tissue with pre-existing mutations to expand and drive tumor promotion, possibly through inflammatory processes similar to our observations in non-smokers with lung cancer.”
The researchers say their findings add to the mounting evidence about the health risks posed by air pollutants and highlight the urgent need for further studies.
“It is very concerning that small pollutant particles in the air and indeed microplastic particles of similar size are getting into the environment when we don’t yet understand their potential to promote cancer,” Swanton said. “There is an urgent need to set up laboratory studies to investigate the effects of these small air pollutant particles on the latency, grade, aggression and progression of breast tumors.”