Urinary 8-hydroxy-2'-deoxyguanosine as a biomarker of oxidative DNA damage induced by ambient pollution in the Normative Aging Study.

BACKGROUND

Studies show that exposure to air pollution damages human health, but the mechanisms are not fully understood. One suggested pathway is via oxidative stress.

OBJECTIVES

This study examines associations between exposure to air pollution and oxidative DNA damage, as indicated by urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations in ageing participants during 2006-2008.

METHODS

We fit linear regression models to examine associations between air pollutants and 8-OHdG adjusting for potential confounders.

RESULTS

8-OHdG was significantly associated with ambient particulate matter ≤2.5 μm in aerodynamic diameter (PM(2.5)), nitrogen dioxide (NO(2)), maximal 1 h ozone (O(3)), sulphate (SO(4)(2-)) and organic carbon (OC), but not with black carbon (BC), carbon monoxide (CO), the number of particles (PN) or elemental carbon (EC). Effects were more apparent with multi-week averages of exposures. Per IQR increases in 21-day averages of PM(2.5), PN, BC, EC, OC, CO, SO(4)(2-), NO(2) and maximal 1 h O(3) were associated with 30.8% (95% CI 9.3% to 52.2%), -13.1% (95% CI -41.7% to 15.5%), 3.0% (95% CI -19.8% to 25.8%), 5.3% (95% CI -23.6% to 34.2%), 24.4% (95% CI 1.8% to 47.1%), -2.0% (95% CI -12.4% to 8.3%), 29.8% (95% CI 6.3% to 53.3%), 32.2% (95% CI 7.4% to 56.9%) and 47.7% (95% CI 3.6% to 91.7%) changes in 8-OHdG, respectively.

CONCLUSIONS

This study suggests that ageing participants experienced an increased risk of developing oxidative DNA injury after exposure to secondary, but not primary, ambient pollutants.