Study finds air pollution linked to increased risk of oral cancer Environment

High levels of air pollution are linked to an increased risk of oral cancer, new research has revealed.

Scientists have already associated high air pollution with a host of health problems, ranging from an increased risk of dementia to asthma, or even changes in the structure of the heart. Recent research suggests that there is no "safety level" of air pollution.

Now, researchers say that at very high levels of air pollution, the risk of developing oral cancer seems to increase.

Taiwanese researchers describe how they discovered the association by analyzing the air pollution data collected by 66 air quality monitoring stations in the country, collected in 2009, and by combining data from medical records of more than 480,000 men. 40 years and over from 2012/13. In total, there were 1,167 cases of oral cancer among participants.

The team focused on the tiny particles of pollution known as PM2.5 and determined that men's exposure to this air pollution was a function of their place of residence. They then sorted participants into four groups, from lowest to highest.

After taking into account factors such as age, exposure to ozone, concentrations of other particles, age, smoking and the fact that men chew betel – a mixture of ingredients including areca nut and betel leaf and which increases the risk of oral cancer – The researchers found that men exposed to the highest levels of PM2.5 had an increased risk of oral cancer.

Relative to men exposed to mean annual PM2.5 levels of 26.74 micrograms (μg) per cubic meter (m³) of air, those exposed to concentrations of 40.37 μg / m³ or more were 43% more likely to develop the disease.

"The mechanism by which this occurs is not clearly understood, which is why additional investigations are needed," the researchers write.

The World Health Organization (WHO) has previously stated that average annual PM2.5 levels should not exceed 10 μg / m³. While in central London, average annual figures have doubled, they are still well below the highest levels seen in the Taiwan study.

However, many other cities in the world have extremely high levels of air pollution. According to WHO figures, the average annual PM2.5 level in Kabul is 86 μg / m³in Beijing it is 85 μg / m³ and in Delhi, it was recorded at 122 μg / m³.

However, the study has limitations, including the fact that it did not take into account the previous exposure of men to air pollution during their lifetime – which may have been higher or lower than their recent exposure.

Professor Frank Kelly, Chair in Environmental Health at King's College London, who did not participate in the study, said it would be useful to examine whether a link between oral cancer and Air pollution is perceived in other countries.

"Air pollution was linked to several types of cancer, including breast, liver, lung and pancreatic cancers. It is therefore not surprising that this new study in Taiwan has established a possible link with oral cancer, "he said. "However, given that air pollution concentrations and the incidence of smoking are much lower in the UK and that we are not chewing betel, we all suggest that the increased risk of developing oral cancer can be unique in Taiwan. "