Association between Ambient Particulate Matter 2.5 Exposure and Mortality in Patients with Hepatocellular Carcinoma

Air pollution is a severe public health problem in Taiwan. Moreover, Taiwan is an endemic area for hepatocellular carcinoma (HCC). This study examined the effect of particulate matter 2.5 (PM_2.5) exposure on mortality in this population. A total of 1003 patients with HCC treated at Chang Gung Memorial Hospital between 2000 and 2009 were included in this study. At the end of the analysis, 288 (28.7%) patients had died. Patients with HCC living in environments with PM_2.5 concentrations of ≥36 µg/m³ had a higher mortality rate than patients living in environments with PM_2.5 concentrations of <36 µg/m³ (36.8% versus 27.5%, p = 0.034). The multivariate Cox regression analysis confirmed that PM_2.5 ≥ 36 µg/m³ was a significant risk factor for mortality (1.584 (1.162-2.160), p = 0.004). A nonlinear relationship was observed between the odds ratio and PM_2.5. The odds ratio was 1.137 (1.015-1.264) for each increment of 5 µg/m³ in PM_2.5 or 1.292 (1.030-1.598) for each increment of 10 µg/m³ in PM_2.5. Therefore, patients with HCC exposed to ambient PM_2.5 concentrations of ≥36 µg/m³ had a 1.584-fold higher risk of death than those exposed to PM_2.5 concentrations of <36 µg/m³. Further studies are warranted.