Large scale epidemiological study associates PM2.5, NO2 pollution with kidney, bladder and colorectal cancer death
Air pollution is classified as carcinogenic to humans given its association with lung cancer, but there is little evidence for its association with cancer at other body sites. However, in a new large-scale prospective study led by the Barcelona Institute of Global Health (ISGlobal), an institution supported by the “la Caixa” Foundation, and the American Cancer Society, researchers observed an association between some air pollutants and mortality from kidney, bladder and colorectal cancer.
The open-access study, published in Environmental Health Perspectives, included more than 600,000 adults in the US who participated in the Cancer Prevention Study II and who were followed for 22 years (from 1982 to 2004). The scientific team examined associations of mortality from cancer at 29 sites with long-term residential exposure to three ambient pollutants: PM2.5, nitrogen dioxide (NO2) and ozone (O3).
More than 43,000 non-lung cancer deaths were registered among the participants. PM2.5 was significantly associated with mortality from kidney and bladder cancer, with a 14 and 13% increase, respectively, for each 4.4 μg/m3 increase in exposure. Exposure to NO2 was associated with colorectal cancer death, with a 6% increase per each 6.5 ppb increment. No significant associations were observed with cancer at other sites.
The results were similar in two-pollutant models including PM2.5 and NO2 and in three-pollutant models with O3. The researchers observed no statistically significant positive associations with death from other types of cancer based on results from adjusted models.
The results from this large prospective study suggest that ambient air pollution was not associated with most non-lung cancer causes of death. Nonetheless, observed associations with mortality from kidney, bladder, and colorectal cancer merit further research, particularly in studies of cancer incidence.—Turner et al.
Turner MC, Krewski D, Diver WR, Pope CA 3rd, Burnett RT, Jerrett M, Marshall JD, Gapstur SM (2017) “Ambient Air Pollution and Cancer Mortality in the Cancer Prevention Study II” Environ Health Perspect. 125(8):087013 doi: 10.1289/EHP1249