VoPham Trang, Bertrand Kimberly A, Yuan Jian-Min, Tamimi Rulla M, Hart Jaime E, Laden Francine
Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
Environ Health. 2017 Aug 18;16(1):89. doi: 10.1186/s12940-017-0299-0.
Hepatocellular carcinoma (HCC), the most commonly occurring type of primary liver cancer, has been increasing in incidence worldwide. Vitamin D, acquired from sunlight exposure, diet, and dietary supplements, has been hypothesized to impact hepatocarcinogenesis. However, previous epidemiologic studies examining the associations between dietary and serum vitamin D reported mixed results. The purpose of this study was to examine the association between ambient ultraviolet (UV) radiation exposure and HCC risk in the U.S.
The Surveillance, Epidemiology, and End Results (SEER) database provided information on HCC cases diagnosed between 2000 and 2014 from 16 population-based cancer registries across the U.S. Ambient UV exposure was estimated by linking the SEER county with a spatiotemporal UV exposure model using a geographic information system. Poisson regression with robust variance estimation was used to calculate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for the association between ambient UV exposure per interquartile range (IQR) increase (32.4 mW/m) and HCC risk adjusting for age at diagnosis, sex, race, year of diagnosis, SEER registry, and county-level information on prevalence of health conditions, lifestyle, socioeconomic, and environmental factors.
Higher levels of ambient UV exposure were associated with statistically significant lower HCC risk (n = 56,245 cases; adjusted IRR per IQR increase: 0.83, 95% CI 0.77, 0.90; p < 0.01). A statistically significant inverse association between ambient UV and HCC risk was observed among males (p for interaction = 0.01) and whites (p for interaction = 0.01).
Higher ambient UV exposure was associated with a decreased risk of HCC in the U.S. UV exposure may be a potential modifiable risk factor for HCC that should be explored in future research.
肝细胞癌（HCC）是最常见的原发性肝癌类型，其在全球的发病率一直在上升。维生素D可通过阳光照射、饮食和膳食补充剂获得，据推测它会影响肝癌的发生。然而，先前关于饮食和血清维生素D之间关联的流行病学研究结果不一。本研究的目的是在美国检验环境紫外线（UV）辐射暴露与HCC风险之间的关联。
监测、流行病学和最终结果（SEER）数据库提供了2000年至2014年间美国16个基于人群的癌症登记处诊断的HCC病例信息。通过使用地理信息系统将SEER县与时空紫外线暴露模型相链接来估计环境紫外线暴露。采用稳健方差估计的泊松回归来计算每增加一个四分位数间距（IQR）（32.4 mW/m）的环境紫外线暴露与HCC风险之间关联的发病率比（IRR）和95%置信区间（CI），同时对诊断时的年龄、性别、种族、诊断年份、SEER登记处以及关于健康状况、生活方式、社会经济和环境因素患病率的县级信息进行调整。
较高水平的环境紫外线暴露与统计学上显著较低的HCC风险相关（n = 56,245例；每增加一个IQR的调整后IRR：0.83，95%CI 0.77，0.90；p < 0.01）。在男性（交互作用p = 0.01）和白人（交互作用p = 0.01）中观察到环境紫外线与HCC风险之间存在统计学上显著的负相关。
在美国，较高的环境紫外线暴露与HCC风险降低相关。紫外线暴露可能是HCC的一个潜在可改变风险因素，应在未来研究中加以探索。
