Air pollution cancer fears grow

Heavily polluted areas may carry a health risk 

Men living in areas with polluted air may be more likely to develop lung cancer, according to scientists. 
Norwegian experts who looked at more than 16,000 men over almost three decades found that those in more polluted areas were more at risk. 
The stronger the concentration of nitrogen dioxide, the greater the chance of developing the disease. 
However, smoking remains the biggest risk factor for developing lung cancer, say experts. 
It has always been tough to pin down the health effects of air pollution, although evidence linking it to cancer has emerged before. 
However, the large scale study has produced clear signs that pollution may influence lung cancer. 
During the follow-up period of 27 years, more than 400 men from the group developed lung cancer. 
The researchers altered their results to take account of smoking habits - but found that, for every rise in concentration of the pollutant nitrogen dioxide (NO2) around their home compared to their home at the start of the study, there was roughly an 8% increase in risk. 
However, there was no increase in cancer risk linked to sulphur dioxide (SO2) levels. 
More evidence
This still means their overall risk of lung cancer is relatively small - but the researchers, from the Norwegian Institute of Public Health, believe that it is clear evidence. 
In the journal Thorax, they wrote: "Urban air pollution may increase the risk of developing lung cancer in men. 
"Compared with smoking the association between air pollution and lung cancer is weak but of expected size." 
However, they said that further, similar research was needed to make sure no other factor was at work in these cases. 
Professor Stephen Spiro, of the British Thoracic Society, said: "This is yet another study which reinforces a small but significant link between urban air pollution and the risk of developing lung cancer. 
"Air pollution does not discriminate between young and old - it is therefore essential that we all work together to minimise pollution levels. 
"We must also conduct further in-depth studies investigating this link."
http://news.bbc.co.uk/1/hi/health/3288781.stm
Thorax 2003;58:1071-1076
 2003 BMJ Publishing Group Ltd & British Thoracic Society 
LUNG CANCER 
1. Lung cancer and air pollution: a 27 year follow up of 16,209 Norwegian men P Nafstad1, L L H?heim2, B Oftedal1, F Gram3, I Holme4, I Hjermann4 and P Leren 41 Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
2. The Norwegian Centre for Health Technology Assessment, SINTEF Unimed, Oslo 3 Norwegian Institute of Air Research, Kjeller, Norway
3. Unit of Preventive Medicine, Ullevl University Hospital, Oslo 
Correspondence to: 
Dr Per Nafstad 
Division of Epidemiology, Norwegian Institute of Public Health, PO Box
4404 Nydalen, 0403 Oslo, Norway; per.nafstad@fhi.no
Background: The well documented urban/rural difference in lung cancer incidence and the detection of known carcinogens in the atmosphere have produced the hypothesis that long term air pollution may have an effect on lung cancer. The association between incidence of lung cancer and long term air pollution exposure was investigated in a cohort of Oslo men followed from 1972/73 to 1998. 
Methods: Data from a follow up study on cardiovascular risk factors among 16 209 40 to 49 year old Oslo men in 1972/73 were linked to data from the Norwegian cancer register, the Norwegian death register, and estimates of average yearly air pollution levels at the participants' home address in 1974 to 1998. Survival analyses, including Cox proportional hazards regression, were used to estimate associations between exposure and the incidence of lung cancer. 
Results: During the follow up period, 418 men developed lung cancer. Controlling for age, smoking habits, and length of education, the adjusted risk ratio for developing lung cancer was 1.08 (95% confidence interval, 1.02 to 1.15) for a 10 ?g/m3 increase in average home address nitrogen oxide (NO2) exposure between 1974 and 1978. Corresponding figures for a 10 ?g/m3 increase in sulphur dioxide (SO2) were 1.01 (0.94 to 1.08). 
Conclusions: Urban air pollution may increase the risk of developing
lung cancer
http://thorax.bmjjournals.com/cgi/content/abstract/58/12/1071

[ back to newsletter ] [ back to homepage ]