Incidence of Cancer and Asbestos-Related Diseases Among
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International Journal of Environmental Research and Public Health Article Incidence of Cancer and Asbestos-Related Diseases among Residents Living near Abandoned Asbestos Mines in South Korea: A Retrospective Cohort Study Using National Health Insurance Database Kyeongmin Kwak 1 , Kyung Ehi Zoh 2 and Domyung Paek 2,3,* 1 Department of Occupational and Environmental Medicine, Korea University Ansan Hospital, Ansan 15355, Korea; [email protected] 2 Department of Environmental Health Sciences, Graduate School of Public Health, Seoul National University, Seoul 08826, Korea; [email protected] 3 Institute of Health and Environment, Seoul National University, Seoul 08826, Korea * Correspondence: [email protected]; Tel.: +82-2-880-2825 Abstract: The use of asbestos has been banned since 2009 in South Korea. However, there is still a risk of exposure to environmental asbestos originating from abandoned asbestos mines. We constructed a retrospective dynamic cohort using the National Health Insurance Database of South Korea. We determined the risk of developing asbestos-related diseases (ARDs) among residents living near asbestos mines compared with those living in the control area and the general population. The risks of asbestosis (adjusted hazards ratio [HR] 65.40, 95% CI = 35.02–122.12) and pleural plaques (adjusted HR 3.55, 95% CI = 1.96–6.41) were significantly increased among residents living near the asbestos mines compared with the control area. The risk of malignant mesothelioma was increased near Citation: Kwak, K.; Zoh, K.E.; Paek, asbestos mines compared with the control area; however, it was not significant (adjusted HR 1.83, 95% D. Incidence of Cancer and CI = 0.61–5.47). When a separate analysis according to sex was conducted, the risk of mesothelioma Asbestos-Related Diseases among Residents Living near Abandoned among male residents was statistically significant (adjusted HR 8.30, 95% CI = 1.04–66.63), and the Asbestos Mines in South Korea: A standardized incidence ratio (SIR) was significantly increased (SIR 3.48, 95% CI = 1.50–6.85). The risk Retrospective Cohort Study Using of ARDs was increased due to environmental asbestos exposure near abandoned asbestos mines in National Health Insurance Database. South Korea. Int. J. Environ. Res. Public Health 2021, 18, 875. https://doi.org/10.3390/ Keywords: asbestos; environmental exposure; non-occupational exposure; asbestos mine; asbestos- ijerph18030875 related disease; cohort study; big data Received: 7 December 2020 Accepted: 16 January 2021 Published: 20 January 2021 1. Introduction Exposure to asbestos causes various diseases such as malignant mesothelioma, lung Publisher’s Note: MDPI stays neutral cancer, asbestosis, pleural effusion, diffuse pleural thickening, laryngeal cancer, and ovarian with regard to jurisdictional claims in cancer [1–3]. Although heavy industrial exposure to asbestos is known to cause lung cancer, published maps and institutional affil- iations. mesothelioma, and asbestosis, there is little evidence of how environmental exposure to asbestos causes these asbestos-related diseases (ARDs). In South Korea, concerns about environmental exposure to asbestos and ARDs among residents living near asbestos textile factories and asbestos mines are increasing. In 2007, Kang analyzed the data on patients with malignant mesothelioma for 10 years in Busan Copyright: © 2021 by the authors. (excluding occupational exposure) and found that the proportional hazards ratio (HR) of Licensee MDPI, Basel, Switzerland. malignant mesothelioma was 6.5 (95% CI = 3.0–14.2) for residents who had ever lived This article is an open access article within 500 m of asbestos textile factories compared with those who had never lived near distributed under the terms and conditions of the Creative Commons them [4]. In addition, the Ministry of Environment (ME) conducted an epidemiological Attribution (CC BY) license (https:// study of 215 residents within 2 km from abandoned asbestos mines in South Chungcheong creativecommons.org/licenses/by/ Province in 2008 [5]. A total of 128 residents had no experience of working in mining, and 4.0/). asbestosis and pleural plaques were confirmed by chest computerized tomography in 23 Int. J. Environ. Res. Public Health 2021, 18, 875. https://doi.org/10.3390/ijerph18030875 https://www.mdpi.com/journal/ijerph Int. J. Environ. Res. Public Health 2021, 18, 875 2 of 15 and 37 of them, respectively. Based on these studies, it can be assumed that environmental ARDs may be prevalent in South Korea. However, these studies were cross-sectional surveys with a small number of subjects, and they were only case or exposure studies without an appropriate control group. There- fore, there is a limitation in confirming the causal relationship between environmental exposure to asbestos and ARDs. To address these limitations, we constructed a retro- spective dynamic cohort using the National Health Insurance Database (NHID) of South Korea for individuals living near asbestos mines for more than five years. To identify the association between environmental exposure to asbestos and ARDs, the incidence of ARDs were compared between residents living near abandoned asbestos mines and those living in the control area and the general population. 2. Materials and Methods 2.1. Data Source We used the NHID to conduct a retrospective cohort study from 2007 and 2018. The NHID is a public database containing data on health care utilization, health screenings, and socio-demographic variables for the entire population of South Korea, created by the Korean National Health Insurance Service (KNHIS) [6]. The NHID has been established since 2002 and includes an “eligibility database”, a “national health screening database”, and a “health care utilization database”. The eligibility database contains information on age, sex, region, income-based insurance contributions, type of insurance, and date of death. The national health screening database contains information on health behaviors such as smoking, drinking, and exercise as well as clinical laboratory results. The health care utilization database contains information on inpatient and outpatient treatment. All disease diagnoses in the NHID are described using the International Classification of Disease, Tenth Revision (ICD-10) codes. We also used the national cancer incidence data of the Korea Central Cancer Registry (KCCR) in 2007–2017. The Korean government started the KCCR in 1980 to promote the registration of cancer cases. Data from the registry are highly accurate for the diagnosis of cancer and are considered reliable in determining actual incidence rates [7,8]. 2.2. Exposed and Control Areas Among the asbestos mines in South Korea, there are 28 asbestos mines at present risk of exposure to asbestos, of which 22 mines are in South Chungcheong Province (nine mines are in Hongseong). Residence information for the subdivision (Eup-Myeon-Dong) of Hongseong was not provided by the NHID because of the protection of personal information. As around 70% of the total population in Hongseong is located within a 5 km radius of abandoned asbestos mines, Hongseong was selected as the exposed area near abandoned asbestos mines in this study (Figure1). In order to secure the homogeneity among regions, we selected the control area in South Chungcheong Province. Buyeo is in the same administrative district with Hongseong, representing a similar size of area. There is no asbestos mine in Buyeo; only one asbestos mine exists within 10 km radius, outside of its boundaries. The region is also less affected by naturally occurring asbestos (NOA). For these reasons, we selected Buyeo as the control area (Figure1). Int. J. J. Environ. Environ. Res. Res. Public Public Health Health 20212021,, 1818,, x 875 3 of 16 15 Figure 1. Exposed and control areas. Figure 1. Exposed and control areas. 2.3. Study Population 2.3. Study Population ARDs usually have a latent period, and a sufficient exposure time is required for ARDs usually have a latent period, and a sufficient exposure time is required for respiratory diseases and cancers to develop due to environmental asbestos exposure. To respiratory diseases and cancers to develop due to environmental asbestos exposure. To clarify the impact and causality of inhabitation around asbestos mines, individuals with clarify the impact and causality of inhabitation around asbestos mines, individuals with less than five years of total residence in the exposed and control areas were excluded. less than five years of total residence in the exposed and control areas were excluded. Those Those who lived in both the exposed and control areas were also excluded. We con- who lived in both the exposed and control areas were also excluded. We constructed a structed a dynamic cohort including individuals in the exposed and control areas for each dynamic cohort including individuals in the exposed and control areas for each target ARD. targetIf individuals, ARD. If individuals, who were in who the were exposed in the and exposed control and areas control at the areas beginning at the ofbeginning the cohort of thestudy, coh migratedort study, to migrated other areas to other outside areas the exposedoutside the and exposed control areasand control and then areas returned, and then we returned,resumed observationswe resumed observations after the previous after residencethe previous period. residence period. 2.4.2.4. Follow Follow-Up-Up P Perioderiod SinceSince the the NHID NHID has has been been established established since since