Air pollution is linked to lung cancer cases in men
By Roger Highfield, Science Editor
EVIDENCE that air pollution is linked to lung cancer is provided today by a study that used lichen as a biological barometer.
Despite firm links with cigarette smoking, the effect of air pollution on the incidence of cancer has been controversial for more than four decades.
Today, however, the journal Nature publishes a large-scale study that uses the diversity of lichen to estimate the extent of air pollution, showing that pollution increases the incidence of lung cancer in young men.
Measuring pollution levels accurately and over large enough areas to study the effect on disease has always been problematic. Changes with time can also confuse the data.
In this study 2,500 lichen measurements were taken over a region where there are only nine pollution gauges. Prof Cesare Cislaghi, of the Institute of Medical Statistics, University of Milan, and Prof Pier Luigi Nimis, of the University of Trieste, used the diversity of lichen species as an indicator, with low diversity linked to high pollution levels.
The lichen are sensitive to sulphur pollution, providing a kind of barometer of the mixture of air pollution produced by combustion in a large area, here the Veneto region in north-east Italy .
The area has about four million inhabitants and enjoys marvellous sunsets over Venice as a result of the air pollution, said Prof Nimis.
Using information from the Italian National Institute of Statistics the scientists found that the incidence of lung cancer in men under 55 was strongly correlated with their lichen "pollution index".
Although the risk was small, Prof Nimis said that the affected population is large, and thus the "impact of pollution in terms of cancer mortality is important".
The incidence of other cancers was not related to pollution, nor was lung cancer in women, whose smoking habits may be more to blame.
