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/m(3) had a higher mortality rate than patients living in environments with PM(2.5) concentrations of <36 µg/m(3) (36.8% versus 27.5%, p = 0.034). The multivariate Cox regression analysis confirmed that PM(2.5) ≥ 36 µg/m(3) 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/m(3) in PM(2.5) or 1.292 (1.030–1.598) for each increment of 10 µg/m(3) in PM(2.5). Therefore, patients with HCC exposed to ambient PM(2.5) concentrations of ≥36 µg/m(3) had a 1.584-fold higher risk of death than those exposed to PM(2.5) concentrations of <36 µg/m(3). Further studies are warranted.