細懸浮微粒重金屬組成與肝癌發生或死亡之相關性研究

Association between the heavy metal constituents in fine particulate matter and the risk of liver cancer incidence or death in Taiwan

利用回溯型世代追蹤設計，評估細懸浮微粒中重金屬組成與肝癌的發生或死亡風險之相關性。方法：納入REVEAL－HBV世代（1991－1992年基線收案）居住在台灣本島之13,515名參與者，透過國家癌症登記與死亡檔進行資料連結，定義追蹤期間（1993－2014）之新發生或死於肝癌病患。參與者之長期暴露濃度乃使用土地利用迴歸模型推估細懸浮微粒中八種重金屬濃度（2002－2006），包含鋇、銅、錳、銻、鋅、鉛、鎳和鎘。本研究使用Cox比例風險模型估計PM2.5中重金屬組成與肝癌之風險比和95％信賴區間。除此之外，還應用雙暴露模型校正細懸浮微粒中重金屬彼此之干擾效應，以評估重金屬組成與肝癌之相關性。結果：本研究追蹤期間共有322名新發生或死於肝癌病例。每增加一個對數尺度單位之PM2.5 Cu（銅），其校正過後之風險比（95％信賴區間, p-value）為1.15（1.03－1.29, 0.017）。在雙暴露模型中，發現PM2.5 Cu與肝癌風險仍然存在正相關，風險比（95％信賴區間, p-value）為1.13（1.00, 1.27, 0.045）。結論：大氣中PM2.5中重金屬組成之銅可能和罹患或死於肝癌之風險有關。

To investigate the association between the heavy metal constituents in PM2.5 and liver cancer incidence or death in a large Taiwanese cohort. Methods: A subset of 13,515 participants of the REVEAL-HBV cohort who lived in Taiwan (excluding outlying islands) during 1991-1992 was adopted for this study. Patients with liver cancer were identified through computerized data linkage with the national cancer registry and death certification systems during 1993-2014. Long-term exposure levels to eight metal constituents of PM2.5 (i.e., Ba, Cu, Mn, Sb, Zn, Pb, Ni, and Cd) during 2002-2006 were determined using land-use regression models. Cox proportional hazards models were used to estimate the hazard ratios (HRs) of PM2.5 metal components on liver cancer incidence or death, after adjustment for potential confounders. To investigate mutual confounding effects, we further applied two-pollutant models for evaluation of the association between metal constituents of PM2.5 and liver cancer. Results: During a median follow-up of 23.2 years, 322 cases of liver cancer or death were identified. With a one-unit increment on a log scale, the adjusted HR of PM2.5 Cu was 1.15 (95% confidence intervals [CIs]: 1.03-1.29). In addition, the association between PM2.5 Cu and liver cancer incidence or death was significant. The two-pollutant model revealed a positive association of PM2.5 Cu with liver cancer incidence or death (HR = 1.13, 95% CI: 1.00-1.27). Conclusions: The findings suggest that exposure to metals within ambient PM2.5, and PM2.5 Cu in particular, may increase the risk of liver cancer occurrence or death.