Analysis of Forty Years of Geographic Disparity in Liver Cancer Mortality and the Influence of Risk Factors

Abstract

Regional disparities in cancer mortality rates are prevalent at all geographic scales. Area factors such as health conditions, behavior patterns, pollution, and socioeconomic status (SES) have significant impacts on cancer disparity. Efforts to determine the risk factors help to identify interventions that can lower disease burdens. In this study, we focus on liver cancer mortality (LCM), which is the second leading cause of cancer-related deaths in the world. Liver cancer rates have shown significant geographic disparities. We used a comprehensive database and applied innovative statistical models to investigate the influences of area factors on geographic disparities in LCM rates in China. To incorporate the long lag period between exposure and mortality, we integrated databases on LCM, other liver diseases, smoking and alcohol use, pollution, health care resources, censuses, and SES across four decades. Spatial random effect models were developed to address the effects of risk factors. Results showed that higher LCM is linked to less access to and lower availability of medical services and higher levels of water pollution. People in the high LCM area more likely worked in the industrial sector and had higher rates of smoking and alcohol use. Compared to Western countries where populations in high-LCM regions usually were those with the lowest SES, this study revealed that China’s high-LCM areas were the mostly rapidly industrializing regions with higher income, more severe water pollution, and a lack of access to medical services. Study results substantially inform potential policy on the allocation of resources for cancer prevention and control in developing countries.

癌症死亡率的地域差异在所有空间尺度上都普遍存在。地区因素（健康状况、行为模式、污染和社会经济地位）对癌症差异有显著影响。确定风险因素, 有助于制定降低疾病负担的干预措施。本研究关注肝癌死亡, 它是世界上第二大癌症死亡原因。肝癌发病率显示出明显的地域差异。我们利用综合数据库和创新的统计模型, 研究了地区因素对中国肝癌死亡率地理差异的影响。为了考虑生病和死亡之间的长期滞后, 我们整合了40年的肝癌死亡、其它肝病、吸烟和饮酒、污染、卫生保健资源、人口普查和社会经济地位的数据库。开发了空间随机效应模型, 以研究风险因素的影响。结果表明, 肝癌死亡越多, 拥有和获取医疗服务的机会越少, 污染程度越高。肝癌死亡多发地区的人们, 更可能在工业部门工作, 吸烟和饮酒的比例也更高。在西方国家, 肝癌死亡多发地区的人口通常处于最低的社会经济地位。这项研究表明, 中国肝癌死亡多发地区大多是快速工业化地区, 收入较高, 水污染更严重, 并缺乏医疗服务。发展中国家需要对癌症预防和控制的资源进行分配, 而本研究结果为相关的政策提供了大量信息。

Las disparidades regionales en las tasas de mortalidad por cáncer predominan en todas las escalas geográficas. Factores areales tales como las condiciones de salubridad, los patrones de comportamiento, polución y estatus socioeconómico (SES) tienen impactos significativos sobre la disparidad del cáncer. Los esfuerzos para determinar los factores de riesgo ayudan a identificar las intervenciones que pueden reducir las cargas de la enfermedad. En este estudio, nos enfocamos en la mortalidad del cáncer del hígado (LCM), que es la segunda causa principal de muertes relacionadas con el cáncer en el mundo. Las tasas de cáncer del hígado han mostrado disparidades geográficas significativas. Nosostros usamos una base de datos amplia y aplicamos modelos estadísticos innovadores para investigar las influencias de factores espaciales sobre las disparidades geográficas en las tasas LCM en China. Para incorporar el largo período de rezago entre la exposición y la mortalidad, integramos las bases de datos sobre LCM, otras enfermedades del hígado, uso de alcohol y consumo de tabaco, polución, recursos para el cuidado de la salud, censos y SES, a lo largo de cuatro décadas. Se desarrollaron modelos de efecto espacial aleatorio para abocar los efectos de los factores de riesgo. Los resultados mostraron que los valores más altos de LCM están ligados con menor disponibilidad de servicios médicos y menor acceso a los mismos y con niveles más altos de contaminación del agua. La gente del área de alta LCM más posiblemente trabajaba en el sector industrial y exhibía tasas más altas de consumo de ttabaco y alcohol. En comparación con los países occidentales, donde las poblaciones en regiones de alta LCM usualmente son las que tieen los valores más bajos de SES, este estudio revela que las áreas de más alta LCM eran las regiones de más rápida industrialización con los niveles de ingreso más altos, contaminación del agua más severa y una falta de acceso a los servicios médicos. Los resultados del estudio informan sustancialmente la política potencial sobre asignación de recursos para la prevención y control del cáncer en países en desarrollo.

Key Words:

• cancer disparity
• China
• cluster analysis
• liver cancer mortality
• spatial model

关键词:

• 癌症差异
• 中国
• 聚类分析
• 肝癌死亡
• 空间模型。

Palabras clave:

• análisis de clúster
• China
• disparidad del cáncer
• modelo espacial
• mortalidad por cáncer del hígado

Acknowledgments

We are indebted to the anonymous reviewers and Ling Bian for their constructive and critical comments that significantly strengthened the article. We would like to thank Matthew H. Ciscel for his comments and Lee Carpenter for her edits of an early draft. Mistakes and oversights remain ours alone.

Additional information

Notes on contributors

Xiaoping Shen

XIAOPING SHEN is Professor of Geography at Central Connecticut State University, New Britain, CT 06050. E-mail: [email protected]. Her research interests include area risk factors influence human health, services for aging persons in China, economic geography, GIS, and cartography.

Limin Wang

LIMIN WANG is Professor, Director of Division of Risk Factor Surveillance, the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xicheng District, Beijing 100050, China. E-mail: [email protected]. Her research interests include chronic disease epidemiology, big data of chronic disease, methodology on chronic disease, and risk factor surveillance.

Xiulan Zhang

XIULAN ZHANG is a Professor of Public Policy at Beijing Normal University, Beijing 100875, China. E-mail: [email protected]. Her research interests include social and health policy, economics of tobacco control, and development studies.

Jiangmei Liu

JIANGMEI LIU is a Research Assistant of Epidemiology and Biostatistics in Division of Vital Registry and Mortality Surveillance, National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xicheng District, Beijing, 100050, China. E-mail: [email protected]. She is Director of Division of Death Cause. Her research interests include study of temporo-spatial trends of mortality rate in China and disease burden of major chronic disease in China.

Lijun Wang

LIJUN WANG is Professor, Director of Division of Vital Registry and Mortality Surveillance, National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Xicheng District, Beijing 100050, China. E-mail: [email protected]. Her research interests include the epidemiology of noncommunicable diseases and disease surveillance.

Li Zhu

LI ZHU is Mathematical Statistician, Division of Cancer Control and Population Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892. E-mail: [email protected]. Her research interests include spatial and spatiotemporal statistics and their application in cancer surveillance research.