A link between air pollution and mouth cancer

After researches revealing connections between air pollution and intelligence’s damages, a new study links pollution to an increased risk of mouth cancer. As the researchers from Taiwan themselves wrote on the Journal od Investigative Medicine, by checking air pollution data from 66 air quality monitoring stations around the country collected in 2009 and by mixing this with data from the heart records of more than 480,000 40 years old and more men from 2012, they discovered the association.

Scientists aimed to tiny particulates of pollution, the so called PM2.5s, comparing this with men’s exposure in the place where they live. Looking data concerning age, exposure to ozone, levels of other particulates, smoking status and other features which predispose to mouth cancer (like betel quid), the researchers found that men exposed to the highest levels of PM2.5s had an increased risk of mouth cancer. Compared with men exposed to average annual PM2.5 levels of 26.74 micrograms (μg) per cubic metre (m3) of air, those exposed to concentrations of 40.37 μg/m3 or higher had 43% greater odds of developing the disease.

«The mechanism through which this occurs is not clearly understood, hence further investigations are required», scientists said. The World Health Organisation (WHO) has already warned about this problem, saying that average annual levels of PM2.5s should not exceed 10 μg/m3. However, in central London the average annual figures are double than this. Nevertheless, WHO found places with pollution levels even higher: the average annual level of PM2.5s in Kabul is 86 μg/m3, while in Beijing it is 85 μg/m3 and in Delhi it has been recorded at 122 μg/m3.

But each study has his limits, and this one doesn’t include the men’s previous exposure to air pollution over their lifetime. Prof Frank Kelly, chair in environmental health at King’s College London, not involved in the study, said it would be useful to explore whether a link between mouth cancer and air pollution is seen in other countries. «Air pollution has previously been linked with several types of cancer, including breast, liver, lung and pancreatic cancer», he said. According to professor, «it is therefore not surprising that this new study in Taiwan has made a possible link with mouth cancer, however, given that air pollution concentrations and smoking incidence are much lower in the UK and we don’t chew betel all suggest that the increased risk of developing mouth cancer may be unique to Taiwan».