You Are What You Breathe

Lung cancer risk increased by even low levels of particulate matter air pollution

(RxWiki News) Air pollution has been linked to an increased risk of lung cancer as well as several other lung conditions. This is one reason why government agencies set standards for air quality levels.

But even the tiniest bits of air pollution may be bad for your lungs if you are exposed over an extended period of time, says a new study.

According to this study, long-term exposure to particulate matter in the air increased the risk of lung cancer even at levels lower than the government agency recommended limit values.

"Follow your local air quality report."

This study was conducted by Ole Raaschou-Nielsen from the Danish Cancer Society Research Center in Copenhagen, Denmark and colleagues.

The aim of the study was to examine the effect of long-term exposure to particulate matter air pollution on the risk of developing lung cancer. Particulate matter is basically tiny particles in the air emitted by traffic, industry and domestic heating.

The researchers specifically looked at exposure to nitrogen oxides and small particulate matter of two kinds: those with a diameter less than 2.5 micrometers (PM2.5) and those with a diameter less than 10 micrometers (PM10).

This study used data from a large collection of studies called the European Study of Cohorts for Air Pollution Effects (ESCAPE) and analyzed results from 17 studies including around 313,000 individuals.

Air pollution levels at home were estimated for the study population. Participants were tracked in national and local cancer registries to check for new lung cancer diagnosis records.

The researchers made sure that the results of the study were not influenced by other factors that could cause lung cancer, such as smoking, diet and occupation.

Of the study participants, 2,095 were diagnosed with lung cancer over a period of around 13 years of follow-up in the cancer registries.

After looking at the data, the researchers found that each increase of 5 micrograms per cubic meter of air in PM2.5 increased the risk of lung cancer by 18 percent.

In the case of PM10 pollution, every increase of 10 micrograms per cubic meter of air increased the risk of lung cancer by 22 percent.

The link between particulate matter air pollution and lung cancer was higher for adenocarcinomas, a type of cancer that affects a large number of non-smokers, compared to other cancer types. There was no link found between nitrogen oxide levels and lung cancer.

"At this stage, we might have to add air pollution, even at current concentrations, to the list of causes of lung cancer and recognize that air pollution has large effects on public health, although, fortunately, like tobacco smoking, it is a controllable factor," the authors concluded.

This study was funded by the European Community’s Seventh Framework Programme. No conflicts of interest or relevant financial relationships were declared.

The results of this study were published July 9 in The Lancet.

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Review Date: 
July 9, 2013