Latency Period Among Asbestosis Cases in South Korea by Demographic and Asbestos Exposure Characteristics

Our plain-English summary of Latency Period Among Asbestosis Cases in South Korea by Demographic and Asbestos Exposure Characteristics, by W.Y. So, M.S. Kang, Y. Hwangbo, et al (Toxics, 2025).

The study

• Authors: W.Y. So, M.S. Kang, Y. Hwangbo, M.R. Lee
• Journal: Toxics
• Published: 2025;13(9)
• Read it: PubMed · Publisher · Free full text

Abstract

Although asbestos use has been banned in many countries, including South Korea, the long latency period of asbestos-related diseases remains a serious public health concern. We conducted a nationwide, registry-based retrospective study to estimate the latency period of asbestosis and identify its determinants. We analyzed exposure history and demographics for 1110 asbestosis cases collected by the Ministry of Environment and the Environmental Health Center for Asbestos in Korea between 2009 and 2021. Mean latency was 45.3 years for asbestosis Grade 1 and 46.3 years for Grade 2. Patients with occupational exposure had shorter latency than those with environmental exposure: 44.4 vs. 46.0 years in Grade 1 (p = 0.010) and 45.0 vs. 47.0 years in Grade 2 (p < 0.001). Within occupations, production-type work showed the shortest latency; within environmental exposure, residence near asbestos-related industries showed the shortest latency, whereas residence near asbestos mines showed the longest. Longer exposure duration (occupational) was associated with shorter latency, and greater residential distance from the source (environmental) with longer latency. Priorities for further investigation include differences by asbestos fiber type and exposure intensity/modality, to inform strengthened occupational health monitoring and targeted surveillance for residents near industrial sources and legacy mines.

In plain English

This nationwide, registry-based retrospective study measured the latency period of asbestosis in South Korea: the time from first asbestos exposure to diagnosis. From 3902 people officially recognized as asbestos victims by 2021, the authors analyzed 1110 asbestosis cases, 234 Grade 1 (severe) and 876 Grade 2 (moderate). Exposure was classed as occupational or environmental (living near an asbestos source). Mean latency was 45.3 years for Grade 1 and 46.3 years for Grade 2, and individual cases ranged from 6 to 86 years. After adjustment, occupationally exposed patients had shorter latency than environmentally exposed patients: 44.4 versus 46.0 years in Grade 1 and 45.0 versus 47.0 years in Grade 2. In Grade 2, workers producing asbestos products had the shortest latency (42.3 years). Among environmentally exposed Grade 2 patients, latency was shortest for those living near asbestos industries (50.4 years) and longest for those living near mines (53.8 years). In Grade 1, differences by job or source were not statistically significant. Living farther from the source was associated with longer latency. Fiber type was not measured, and the authors noted possible registry and recall bias.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Nationwide, registry-based retrospective study of latency, using univariate analysis, analysis of covariance (ANCOVA) and multiple linear regression
• Who was studied: 1110 asbestosis cases (234 Grade 1 severe, 876 Grade 2 moderate) drawn from 3902 people officially recognized as asbestos victims in South Korea by 2021. Data were collected by the Ministry of Environment and the Environmental Health Center for Asbestos between 2009 and 2021. 2387 people with diagnoses other than asbestosis and 405 with unclear exposure histories were excluded.
• Exposure: Occupational exposure (at least one year of work involving asbestos fiber contact) in four job groups: building construction or demolition, production of asbestos products such as cements, slates and textiles, maintenance and repair, and asbestos extraction, conveyance and grinding. Environmental exposure (at least one year living near asbestos mines, industries, shipyards or asbestos-containing buildings). People with both kinds of exposure were counted as occupational. Fiber type was not recorded for individuals.
• Main results:
  • Mean (standard deviation) latency was 45.3 (14.4) years for Grade 1 and 46.3 (14.9) years for Grade 2.
  • Grade 1, adjusted: occupationally exposed patients had a latency of 44.4 years versus 46.0 years for environmentally exposed patients (p = 0.010).
  • Grade 2, adjusted: latency was 45.0 years for occupationally exposed patients versus 47.0 years for environmentally exposed patients (p less than 0.001 in Table 3).
  • Grade 1: production workers (42.0 years) and residents near asbestos industries (47.4 years) had the shortest latencies, but the differences were not statistically significant (p = 0.214 and 0.348).
  • Grade 2: production-type workers had shorter latency (42.3 years) than other occupational groups (p less than 0.001).
  • Grade 2, environmental exposure: residents near asbestos industries had shorter latency (50.4 years) than other groups (p = 0.001), and those who had lived near asbestos mines had the longest (53.8 years).
  • Occupational exposure: longer exposure duration was associated with shorter latency. In Table 4 this was statistically significant for Grade 2 (B −0.159 per year, 95% CI −0.288 to −0.030, p = 0.039) but not for Grade 1 (B −0.051, p = 0.061).
  • Environmental exposure: greater distance from the asbestos source to the residence was associated with longer latency, by 1.131 years per km in Grade 1 (95% CI 0.001 to 2.260, p = 0.048) and 0.997 years per km in Grade 2 (95% CI 0.035 to 1.959, p = 0.036). Exposure duration was not significantly associated with latency in this group.
  • In both grades, each one-year increase in age at first exposure was associated with about a one-year decrease in latency.
  • Latency did not differ significantly by smoking status in either grade.
  • Individual latency periods ranged from 6 to 86 years.
• The authors' conclusion: The authors concluded that occupationally exposed patients had shorter latency than environmentally exposed patients. In their wording, type of occupation, distance to the exposure source and age at first exposure were significantly associated with shorter latency periods. They called for further investigation of exposure characteristics and for prospective studies.
• Limitations the authors state:
  • Because the data come from a national registry, they may be affected by selection and reporting biases, including under-counting of mild or asymptomatic cases.
  • Interactions between smoking and exposure characteristics were not modeled because the subgroups were small, especially current smokers.
  • No biomarker data, such as genetic susceptibility, were available, leaving room for residual confounding.
  • Fiber type was not measured for individuals, so the authors' explanation of differences between job and source groups by fiber type is based on the literature and is inferential.
  • Exposure histories may be misclassified or affected by recall bias, particularly for environmental exposure, which could lead to underestimating latency.

Topics

Medical terms in this study, explained in our Lexicon: Latency, Asbestos Exposure, Exposure History, Occupational Exposure, Environmental Exposure.

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