Air Pollution and Cancer


A new study published in Cancer Epidemiology, Biomarkers & Prevention concluded that long term exposure to environmental pollutants are associated with increased risk of mortality for many types of cancer in an elderly population in Hong Kong adding to a growing concern about the health risk of prolonged exposure to ambient fine particle materials. Some particles found in air included hydrocarbons and heavy metals produced by transportation and power generators. The focus of the study was on fine particles less than 2.5 micrometers (PM2.5) in diameter. It was found that for every 10 microgram per cubic meter (µg/m3) of increased exposure to PM2.5. the risk of dying from cancer rose by 22 percent. Researchers said “The implications for other similar cities around the world are that PM2.5 must be reduced to reduce the health burden. Air pollution remains a clear, modifiable public health concern.”  In relation to cancer the researchers said ” Long-term exposure to particulate matter has been associated with mortality mainly from cardiopulmonary causes and lung cancer, but there has been few studies showing an association with mortality from other cancers.  We suspect that these particulates could have an equivalent effect on cancers elsewhere in the body.”

Sixty six thousand two hundred eighty people between age 65 and older between 1998 and 2001 were followed until 2011. Causes of death within the group were determined from the Hong Kong registration.  Annual concentration of PM2.5 at their homes was estimated using satellite data and fixed-site monitoring.  Findings were adjusted for smoking status, and deaths occurring within 3 years of baseline.    Results showed that for every 10 ug/m3 of increased exposure   to PM2.5, the risk of dying from any cancer rose by 22 percent. This increase was also associat4ed with a 42 percent increased risk of mortality from cancer in the upper digestive tract and a 35 per4cent increase risk of mortality from accessory digestive organs including the liver, bile ducts, bladder, and pancreas.  For women, every increase of 10 ug/m3 increase in exposure to PM2.5 produced an 80 percent increased risk of mortality from breast cancer, and for me this produced a 36 percent increased risk of dying of lung cancer. Causes for these associations  may include defects in DNA repair functions, alternations in the body’s immune response, or inflammation that triggers angiogenesis, that allows the growth of new blood vessels allowing tumors to spread according to the researchers. In addition, heavy metal pollution could affect gut microbiota and influence the development of cancer in the digestive system, they postulate. Researchers say we mist be cautious about the findings because pollution is only one risk factor and others such as diet and exercise may be more identifiable and modifiable.

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