Cancer mortality risks from long-term exposure to ambient fine particle

Background: Few studies have assessed long-term effects of particulate matter (PM) with aerodynamic diameter < 2.5 μm (PM_2.5) on mortality for causes of cancer other than the lung; we assessed the effects on multiple causes. In Hong Kong, most people live and work in urban or suburban areas with high-rise buildings. This facilitates the estimation of PM_2.5 exposure of individuals, taking into account the height of residence above ground level for assessment of the long-term health effects with sufficient statistical power. Methods: We recruited 66,820 persons who were ≥65 in 1998 to 2001 and followed up for mortality outcomes until 2011. Annual concentrations of PM at their residential addresses were estimated using PM_2.5 concentrations measured at fixed-site monitors, horizontal?vertical locations, and satellite data. We used Cox regression model to assess theHRof mortality for cancer per 10 μg/m³ increase of PM_2.5. Results: PM_2.5 was associated with increased risk of mortality for all causes of cancer [HR, 1.22 (95% CI, 1.11?1.34)] and for specific cause of cancer in upper digestive tract [1.42 (1.06?1.89)], digestive accessory organs [1.35 (1.06?1.71)] in all subjects; breast [1.80 (1.26?2.55)] in females; and lung [1.36 (1.05? 1.77)] in males. Conclusions: Long-term exposures toPM_2.5 are associated with elevated risks of cancer in various organs. Impact: This study is particularly timely in China, where compelling evidence is needed to support the pollution control policy to ameliorate the health damages associated with economic growth.