Health Effects of Microplastic Exposures: Current Issues and Perspectives in South Korea

Microplastics are environmental pollutants that prevail in the oceans, remote islands, and polar regions. Exposure to microplastics presents a major emerging threat to the ecosystems due to their potential adverse effects. Herein, we reviewed the literature to provide an up-to-date synopsis of the current understanding of the sources, compositions, and adverse effects of microplastics in humans and the environment. Most studies on microplastics have focused on developing standardized methods for monitoring the occurrence, distribution, and movement of microplastics in the environment, as well as developing microplastic substitutes; however, although humans are exposed to microplastics via various routes, research on the adverse effects of microplastics in humans remains limited. Little is known about the impact of microplastics on human health and the toxic effects that may vary depending on the type, size, shape, and concentration of microplastics. Therefore, more research is needed to understand the cellular and molecular mechanisms of microplastic toxicity and related pathologies.

Associations of Particulate Matter Exposures With Brain Gray Matter Thickness and White Matter Hyperintensities: Effect Modification by Low-Grade Chronic Inflammation

Background@#Numerous studies have shown the effect of particulate matter exposure on brain imaging markers. However, little evidence exists about whether the effect differs by the level of low-grade chronic systemic inflammation. We investigated whether the level of c-reactive protein (CRP, a marker of systemic inflammation) modifies the associations of particulate matter exposures with brain cortical gray matter thickness and white matter hyperintensities (WMH). @*Methods@#We conducted a cross-sectional study of baseline data from a prospective cohort study including adults with no dementia or stroke. Long-term concentrations of particulate matter ≤ 10 µm in diameter (PM10) and ≤ 2.5 µm (PM2.5) at each participant’s home address were estimated. Global cortical thickness (n = 874) and WMH volumes (n = 397) were estimated from brain magnetic resonance images. We built linear and logistic regression models for cortical thickness and WMH volumes (higher versus lower than median), respectively. Significance of difference in the association between the CRP group (higher versus lower than median) was expressed as P for interaction. @*Results@#Particulate matter exposures were significantly associated with a reduced global cortical thickness only in the higher CRP group among men (P for interaction = 0.015 for PM10 and 0.006 for PM2.5). A 10 μg/m3 increase in PM10 was associated with the higher volumes of total WMH (odds ratio, 1.78; 95% confidence interval, 1.07–2.97) and periventricular WMH (2.00; 1.20–3.33). A 1 μg/m3 increase in PM2.5 was associated with the higher volume of periventricular WMH (odds ratio, 1.66; 95% confidence interval, 1.08–2.56). These associations did not significantly differ by the level of high sensitivity CRP. @*Conclusion@#Particulate matter exposures were associated with a reduced global cortical thickness in men with a high level of chronic inflammation. Men with a high level of chronic inflammation may be susceptible to cortical atrophy attributable to particulate matter exposures.

All-Cause and Cause-Specific Mortality Attributable to Seasonal Influenza: A Nationwide Matched Cohort Study

Background@#Although influenza poses substantial mortality burden, most studies have estimated excess mortality using time-aggregated data. Here, we estimated mortality risk and population attributable fraction (PAF) attributed to seasonal influenza using individual-level data from a nationwide matched cohort. @*Methods@#Individuals with influenza during four consecutive influenza seasons (2013–2017) (n = 5,497,812) and 1:4 age- and sex-matched individuals without influenza (n = 20,990,683) were identified from a national health insurance database. The endpoint was mortality within 30 days after influenza diagnosis. All-cause and cause-specific mortality risk ratios (RRs) attributed to influenza were estimated. Excess mortality, mortality RR, and PAF of mortality were determined, including for underlying disease subgroups. @*Results@#Excess mortality rate, mortality RR, and PAF of all-cause mortality were 49.5 per 100,000, 4.03 (95% confidence interval [CI], 3.63–4.48), and 5.6% (95% CI, 4.5–6.7%). Cause-specific mortality RR (12.85; 95% CI, 9.40–17.55) and PAF (20.7%; 95% CI, 13.2– 27.0%) were highest for respiratory diseases. In subgroup analysis according to underlying disorders, PAF of all-cause mortality was 5.9% (95% CI, 0.6–10.7%) for liver disease, 5.8% (95% CI, 2.9–8.5%) for respiratory disease, and 3.8% (95% CI, 1.4–6.1%) for cancer. @*Conclusion@#Individuals with influenza had a 4-fold higher mortality risk than individuals without influenza. Preventing seasonal influenza may lead to 5.6% and 20.7% reductions in all-cause and respiratory mortality, respectively. Individuals with respiratory disease, liver disease, and cancer may benefit from prioritization when establishing influenza prevention strategies.

Cost-Benefit Analysis of Tafenoquine for Radical Cure of Plasmodium vivax Malaria in Korea

Background@#Plasmodium vivax malaria has a persistent liver stage that causes relapse, and introducing tafenoquine to suppress relapse could aid in disease eradication. Therefore, we assessed the impact of tafenoquine introduction on P. vivax malaria incidence and performed a cost-benefit analysis from the payer’s perspective. @*Methods@#We expanded the previously developed P. vivax malaria dynamic transmission model and calibrated it to weekly civilian malaria incidences in 2014–2018. Primaquine and tafenoquine scenarios were considered by assuming different relapse probabilities, and relapse and total P. vivax malaria cases were predicted over the next decade for each scenario. We then estimated the number of cases prevented by replacing primaquine with tafenoquine. The cost and benefit of introducing tafenoquine were obtained using medical expenditure from a nationwide database, and a cost-benefit analysis was conducted. A probabilistic sensitivity analysis was performed to assess the economic feasibility robustness of tafenoquine introduction under uncertainties of model parameters, costs, and benefits. @*Results@#Under 0.04 primaquine relapse probability, the introduction of tafenoquine with relapse probability of 0.01 prevented 129 (12.27%) and 35 (77.78%) total and relapse cases, respectively, over the next decade. However, under the same relapse probability as primaquine, introducing tafenoquine had no additional preventative effect. The 14-day primaquine treatment cost was $3.71. The tafenoquine and the glucose-6-phosphate dehydrogenase rapid diagnostic testing cost $57.37 and $7.76, totaling $65.13. The average medical expenditure per malaria patient was estimated at $1444.79. The cost-benefit analysis results provided an incremental benefit-cost ratio (IBCR) from 0 to 3.21 as the tafenoquine relapse probability decreased from 0.04 to 0.01. The probabilistic sensitivity analysis showed an IBCR > 1, indicating that tafenoquine is beneficial, with a probability of 69.1%. @*Conclusion@#Tafenoquine could reduce P. vivax malaria incidence and medical costs and bring greater benefits than primaquine.

Regional Gray Matter Volume Related to High Occupational Stress in Firefighters

Background@#Firefighters inevitably encounter emotionally and physically stressful situations at work. Even firefighters without diagnosed post-traumatic stress disorder receive clinical attention because the nature of the profession exposes them to repetitive trauma and high occupational stress. This study investigated gray matter abnormalities related to high occupational stress in firefighters using voxel-based morphometry (VBM) and surface-based morphometry (SBM). @*Methods@#We assessed 115 subjects (112 males and 3 females) using magnetic resonance imaging and evaluated occupational stress by the Korean Occupational Stress Scale-26 (KOSS-26). Subjects were classified into highly or lowly stressed groups based on the median value of the KOSS-26. @*Results@#In VBM analysis, we found that firefighters with high occupational stress had lower gray matter volume (GMV) in both sides of the insula, the left amygdala, the right medial prefrontal cortex (mPFC), and the anterior cingulate cortex than firefighters with low occupational stress. In SBM analysis based on regions of interest, the GMV of the bilateral insula and right mPFC were also lower in the highly stressed group. Within the highly stressed group, low GMV of the insula was significantly correlated with the length of service (left: r = −0.347, P = 0.009; right: r = −0.333, P = 0.012). @*Conclusion@#Our findings suggest that regional GMV abnormalities are related to occupational stress. Regional gray matter abnormalities and related emotional dysregulation may contribute to firefighter susceptibility to burnout.

Management of the COVID-19 Pandemic in the Republic of Korea from the Perspective of Governance and Public-Private Partnership

The government of the Republic of Korea (ROK) has established relevant laws and a master plan for infectious disease control and prevention based on their experiences with past epidemics. In addition, the Ministry of Health and Welfare has designed a standard manual for risk management that involves pan-governmental crisis management systems. This national infectious disease management system is constantly being supplemented and developed in face of infectious disease-related crises. In this study, we set out to present directions for infectious disease prevention and flow of management and governance between central and local governments to ensure systematic quarantine activities in the ROK. During the coronavirus disease 2019 (COVID-19) pandemic, public-private partnerships have been established to collect, provide, process, and disseminate information for effective quarantine. This has enabled the development and rapid approval of test kits, the tracking of cases, and the allocation of appropriate resources for patient treatment. Additionally, the Infectious Disease Control Agency has actively utilized information and communication technology platforms to disclose information necessary in real-time for COVID-19 quarantine and management. Overall, these efforts have played an important role in epidemiological investigations, patient management, and quarantine in the early stages of the COVID-19 pandemic.

Prevalence of Dementia in Korea Based on Hospital Utilization Data from 2008 to 2016

Purpose@#Dementia is an important health issue in Korea due to its associated medical costs. Our study aimed to estimate the prevalence of dementia in Korea by analyzing hospital utilization rates. @*Materials and Methods@#We examined National Health Insurance data from 2008 to 2016 and identified all dementia cases. Crude and age- and sex-standardized prevalence were calculated. A generalized linear mixed model was used to estimate prevalence ratios. @*Results@#We identified 176746 and 530269 dementia cases in 2008 and 2016, respectively. Alzheimer’s disease was the most common dementia subtype (65.4% and 86.1% in 2008 and 2016, respectively). Across all age groups, the prevalence of dementia increased consistently: the increase was prominent among patients ≥85 years of age. Among patients ≥65 years of age, crude prevalence was estimated at 31.3 and 72.2 per 1000 population in 2008 and 2016, respectively. Age- and sex-standardized prevalence increased from 31.3 to 62.0 per 1000 population between 2008 and 2016, respectively. The prevalence ratio for dementia in 2016 was 2.02 times (95% confidence interval, 2.01–2.03) higher than that in 2008. When adjusted for age, dementia was more prevalent among females. The most common comorbidity was hypertension, followed by diabetes and stroke. @*Conclusion@#Our results demonstrated that hospital utilization for dementia increased significantly from 2008 to 2016, reflecting a proportional increase in the prevalence of dementia. Korean healthcare policy must prioritize dementia treatment.

Role of Primary Care and Challenges for Public–Private Cooperation during the Coronavirus Disease 2019 Pandemic: An Expert Delphi Study in South Korea

Purpose@#The aim of this study was to explore the role of primary care facilities and their support measures in response to coronavirus disease 2019 (COVID-19) and to identify challenges to achieving public–private cooperation in South Korea. @*Materials and Methods@#Twenty-four leading experts were selected and recruited to participate in this iterative web-based Delphi study. An open-ended questionnaire was administered to collect the expert panel’s views in the first round. In the second round, the panel was asked to rate on a 5-point Likert scale their agreement with individual items gleaned from qualitative content analysis of views expressed in the first round. The participants were offered the opportunity to reevaluate and correct their initial responses in subsequent rounds. Responses in the second and following rounds were analyzed using quantitative descriptive statistics. @*Results@#The first and second rounds were completed by 54.2% (n=13/24) and 58.3% (n=14/24) of the selected panel, respectively, while 10 out of these 14 participants completed the third round. The panel cited in-person essential medical services, telehealth for fever/respiratory symptoms, surveillance for influenzae-like illness, and minimization of spread to staff as important and appropriate roles of primary care, which are urgent and feasible during a pandemic. Regarding conditions/support for these roles, the panel indicated that institutional support and funding for separate areas, workforce, and telehealth, along with public-private collaborative governance, are urgent, but not feasible. @*Conclusion@#This study provides guidance on strategies for continuing the required roles of primary care and highlights a need to strengthen public-private partnerships during pandemic events in Korea.

High Level of Real Urban Air Pollution Promotes Cardiac Arrhythmia in Healthy Mice

Background and Objectives@#Ambient particulate matter (PM) in real urban air pollution (RUA) is an environmental health risk factor associated with increased cardiac events. This study investigated the threshold level to induce arrhythmia, as well as arrhythmogenic mechanism of RUA that mainly consisted of PM <2.5 μm in aerodynamic diameter close to ultrafine particles. @*Methods@#RUA was artificially produced by a lately developed pyrolysis based RUA generator.C57BL/6 mice were divided into 4 groups: a control group (control, n=12) and three groups with exposure to RUA with the concentration of 200 µg/㎥ (n=12), 400 µg/㎥ (n=12), and 800 µg/㎥ (n=12). Mice were exposed to RUA at each concentration for 8 hr/day and 5 day/week to mimic ordinary human activity during 3 weeks. @*Results@#The QRS and QTc intervals, as well as intracellular Ca2+ duration, apicobasal action potential duration (APD) gradient, fibrosis, and inflammation of left ventricle of mouse hearts were increased dose-dependently with the increase of RUA concentration, and significantly increased at RUA concentration of 400 µg/㎥ compared to control (all p<0.001). In mice exposed to RUA concentration of 800 µg/㎥ , spontaneous ventricular arrhythmia was observed in 42%, with significant increase of inflammatory markers, phosphorylated Ca2+ /calmodulindependent protein kinase II (CaMKII), and phospholamban (PLB) compared to control. @*Conclusions@#RUA could induce electrophysiological changes such as APD and QT prolongation, fibrosis, and inflammation dose-dependently, with significant increase of ventricular arrhythmia at the concentration of 400 µg/㎥ . RUA concentration of 800 µg/㎥ increased phosphorylation of CaMKII and PLB.

Management of the COVID-19 Pandemic in the Republic of Korea from the Perspective of Governance and Public-Private Partnership

The government of the Republic of Korea (ROK) has established relevant laws and a master plan for infectious disease control and prevention based on their experiences with past epidemics. In addition, the Ministry of Health and Welfare has designed a standard manual for risk management that involves pan-governmental crisis management systems. This national infectious disease management system is constantly being supplemented and developed in face of infectious disease-related crises. In this study, we set out to present directions for infectious disease prevention and flow of management and governance between central and local governments to ensure systematic quarantine activities in the ROK. During the coronavirus disease 2019 (COVID-19) pandemic, public-private partnerships have been established to collect, provide, process, and disseminate information for effective quarantine. This has enabled the development and rapid approval of test kits, the tracking of cases, and the allocation of appropriate resources for patient treatment. Additionally, the Infectious Disease Control Agency has actively utilized information and communication technology platforms to disclose information necessary in real-time for COVID-19 quarantine and management. Overall, these efforts have played an important role in epidemiological investigations, patient management, and quarantine in the early stages of the COVID-19 pandemic.

Prevalence of Dementia in Korea Based on Hospital Utilization Data from 2008 to 2016

Purpose@#Dementia is an important health issue in Korea due to its associated medical costs. Our study aimed to estimate the prevalence of dementia in Korea by analyzing hospital utilization rates. @*Materials and Methods@#We examined National Health Insurance data from 2008 to 2016 and identified all dementia cases. Crude and age- and sex-standardized prevalence were calculated. A generalized linear mixed model was used to estimate prevalence ratios. @*Results@#We identified 176746 and 530269 dementia cases in 2008 and 2016, respectively. Alzheimer’s disease was the most common dementia subtype (65.4% and 86.1% in 2008 and 2016, respectively). Across all age groups, the prevalence of dementia increased consistently: the increase was prominent among patients ≥85 years of age. Among patients ≥65 years of age, crude prevalence was estimated at 31.3 and 72.2 per 1000 population in 2008 and 2016, respectively. Age- and sex-standardized prevalence increased from 31.3 to 62.0 per 1000 population between 2008 and 2016, respectively. The prevalence ratio for dementia in 2016 was 2.02 times (95% confidence interval, 2.01–2.03) higher than that in 2008. When adjusted for age, dementia was more prevalent among females. The most common comorbidity was hypertension, followed by diabetes and stroke. @*Conclusion@#Our results demonstrated that hospital utilization for dementia increased significantly from 2008 to 2016, reflecting a proportional increase in the prevalence of dementia. Korean healthcare policy must prioritize dementia treatment.

Role of Primary Care and Challenges for Public–Private Cooperation during the Coronavirus Disease 2019 Pandemic: An Expert Delphi Study in South Korea

Purpose@#The aim of this study was to explore the role of primary care facilities and their support measures in response to coronavirus disease 2019 (COVID-19) and to identify challenges to achieving public–private cooperation in South Korea. @*Materials and Methods@#Twenty-four leading experts were selected and recruited to participate in this iterative web-based Delphi study. An open-ended questionnaire was administered to collect the expert panel’s views in the first round. In the second round, the panel was asked to rate on a 5-point Likert scale their agreement with individual items gleaned from qualitative content analysis of views expressed in the first round. The participants were offered the opportunity to reevaluate and correct their initial responses in subsequent rounds. Responses in the second and following rounds were analyzed using quantitative descriptive statistics. @*Results@#The first and second rounds were completed by 54.2% (n=13/24) and 58.3% (n=14/24) of the selected panel, respectively, while 10 out of these 14 participants completed the third round. The panel cited in-person essential medical services, telehealth for fever/respiratory symptoms, surveillance for influenzae-like illness, and minimization of spread to staff as important and appropriate roles of primary care, which are urgent and feasible during a pandemic. Regarding conditions/support for these roles, the panel indicated that institutional support and funding for separate areas, workforce, and telehealth, along with public-private collaborative governance, are urgent, but not feasible. @*Conclusion@#This study provides guidance on strategies for continuing the required roles of primary care and highlights a need to strengthen public-private partnerships during pandemic events in Korea.

Comparative occurrence of ischemic stroke with the rhythm versus rate control strategy in a national prospective cohort of atrial fibrillation

Background/Aims@#Comparative occurrence of ischemic stroke for rhythm versus rate control strategy in patients with non-valvular atrial fibrillation (NVAF) is still inconclusive. The purpose of this study was to investigate whether the rhythm control strategy is associated with a lower risk of ischemic stroke compared to the rate control strategy in NVAF patients. @*Methods@#The CODE-AF registry prospectively enrolled 6,280 consecutive patients who were treated for NVAF at 10 tertiary referral centers in South Korea. Of these, 2,513 NVAF patients (age, 67 ± 10 years; male, 61.8%) were clinically followed up for over 1-year and divided into rate and rhythm control groups. @*Results@#Those treated with the rhythm control strategy were younger and had less proportions of underlying disease compared to those treated with the rate control strategy. After the propensity matching analysis, those treated with the rhythm control strategy had similar baseline characteristics including the CHA 2 DS 2 -VASC score compared to those treated with the rate control strategy.The rate of oral anticoagulation, all bleeding, and hospitalization were also similarly between the two groups. The incidence rate of ischemic stroke in the rhythm control group was significantly lower than in the rate control group (0.7 vs. 6.9 per 1,000 person-years, p = 0.011). @*Conclusions@#The rhythm control strategy demonstrated a beneficial effect to lower the risk of ischemic stroke during a 1-year follow-up compared to the rate control strategy.

High Level of Real Urban Air Pollution Promotes Cardiac Arrhythmia in Healthy Mice

Background and Objectives@#Ambient particulate matter (PM) in real urban air pollution (RUA) is an environmental health risk factor associated with increased cardiac events. This study investigated the threshold level to induce arrhythmia, as well as arrhythmogenic mechanism of RUA that mainly consisted of PM <2.5 μm in aerodynamic diameter close to ultrafine particles. @*Methods@#RUA was artificially produced by a lately developed pyrolysis based RUA generator.C57BL/6 mice were divided into 4 groups: a control group (control, n=12) and three groups with exposure to RUA with the concentration of 200 µg/㎥ (n=12), 400 µg/㎥ (n=12), and 800 µg/㎥ (n=12). Mice were exposed to RUA at each concentration for 8 hr/day and 5 day/week to mimic ordinary human activity during 3 weeks. @*Results@#The QRS and QTc intervals, as well as intracellular Ca2+ duration, apicobasal action potential duration (APD) gradient, fibrosis, and inflammation of left ventricle of mouse hearts were increased dose-dependently with the increase of RUA concentration, and significantly increased at RUA concentration of 400 µg/㎥ compared to control (all p<0.001). In mice exposed to RUA concentration of 800 µg/㎥ , spontaneous ventricular arrhythmia was observed in 42%, with significant increase of inflammatory markers, phosphorylated Ca2+ /calmodulindependent protein kinase II (CaMKII), and phospholamban (PLB) compared to control. @*Conclusions@#RUA could induce electrophysiological changes such as APD and QT prolongation, fibrosis, and inflammation dose-dependently, with significant increase of ventricular arrhythmia at the concentration of 400 µg/㎥ . RUA concentration of 800 µg/㎥ increased phosphorylation of CaMKII and PLB.

Current Anticoagulant Usage Patterns and Determinants in Korean Patients with Nonvalvular Atrial Fibrillation

Does Emotional Labor Increase the Risk of Suicidal Ideation among Firefighters?

Cohort Profile: Firefighter Research on the Enhancement of Safety and Health (FRESH), a Prospective Cohort Study on Korean Firefighters

40 years or new hires with less than 1 year of service.

Characteristics of symptom burden in atrial fibrillation with concomitant heart failure

Background@#Symptom burden is an important factor in determining the treatment of atrial fibrillation (AF). AF is frequently accompanied by heart failure (HF). This study investigated the characteristics of AF symptoms with concomitant HF. @*Methods@#A total of 4885 patients with AF were consecutively enrolled through a prospective observational registry (the Comparison Study of Drugs for Symptom Control and Complication Prevention of Atrial Fibrillation [CODE-AF] registry). Clinically diagnosed HF was divided into three categories (preserved, mid-range, and reduced ejection fraction [EF]). Symptom severity was assessed using the European Heart Rhythm Association (EHRA) classification. @*Results@#The presence of AF-related symptoms was comparable irrespective of concomitant HF. Patients with HF with reduced EF demonstrated severe (EHRA classes 3 and 4) and atypical symptoms. HF with preserved EF was also associated with atypical symptoms. Female sex and AF type were associated with the presence of symptoms in AF without HF, and non-maintenance of sinus rhythm and increased left atrial pressure (E/e′ ≥ 15) were factors related to the presence of symptoms in AF with HF. @*Conclusion@#AF with concomitant HF presented with more severe and atypical symptoms than AF without HF. Maintaining the sinus rhythm and reducing the E/e’ ratio are important factors for reducing symptoms in AF with concomitant HF.

Differences in anticoagulation strategy and outcome in atrial fibrillation patients with chronic kidney disease: a CODE‑AF registry study

Purpose@#Dose reduction of non-vitamin K antagonist oral anticoagulants (NOACs) is indicated in patients with atrial fibrillation (AF) with renal impairment. This study investigated anticoagulation patterns and outcomes in patients with chronic kidney disease (CKD). @*Materials and methods@#In a prospective observational registry (CODE-AF), 3445 patients with non-valvular AF including 1129 with CKD (estimated glomerular filtration rate ≤ 60 mL min−1 1.73 m−2) were identified between June 1, 2016, and July 3, 2017. @*Results@#Compared with patients with no-CKD, patients with CKD more frequently had a high stroke risk (94.9% vs. 67.0%, p < 0.001) and higher NOAC usage rate (61.1% vs. 47.8%, p < 0.001). Among 718 patients with renal indication for dose reduction (RIDR), 7.5% were potentially overdosed. Among 2587 patients with no-RIDR, 79% were potentially underdosed. Compared with patients with no-RIDR, the underdose rates of dabigatran (0% vs. 88.6%, p = 0.001) and rivaroxaban (0% vs. 79.5%, p = 0.001) were lower in patients with RIDR. However, the underdose rate of apixaban was not different (62.5% vs. 53.9%, p = 0.089). The overdose rate of dabigatran (7.5% vs. 0%) and rivaroxaban (13.7% vs. 0%) was higher in RIDR than in no-RIDR patients. Stroke/transient ischemic attack was significantly higher in CKD patients (1.4 vs. 0.6 per 100 person-years, p = 0.045). Aspirin significantly increased minor bleeding in CKD patients compared with controls (p = 0.037). @*Conclusion@#CKD patients might have a high stroke risk and NOAC usage rate. The underdose rate of NOACs decreased in CKD patients, except for apixaban. Aspirin significantly increased minor bleeding in CKD patients.

Structural and Resting-State Brain Alterations in Trauma-Exposed Firefighters: Preliminary Results

Purpose@#To analyze the altered brain regions and intrinsic brain activity patterns in trauma-exposed firefighters without posttraumatic stress disorder (PTSD). @*Materials and Methods@#Resting-state functional MRI (rsfMRI) was performed for all subjects. Thirty-one firefighters over 40 years of age without PTSD (31 men; mean age, 49.8 ± 4.7 years) were included. Twenty-six non-traumatized healthy controls (HCs) (26 men; mean age, 65.3 ± 7.84 years) were also included. Voxel-based morphometry was performed to investigate focal differences in the brain anatomy. Seed-based functional connectivity analysis was performed to investigate differences in spontaneous brain characteristics. @*Results@#The mean z-scores of the Seoul Verbal Learning Test for immediate and delayed recall, Controlled Oral Word Association Test (COWAT) score for animals, and COWAT phonemic fluency were significantly lower in the firefighter group than in the HCs, indicating decreased neurocognitive function. Compared to HCs, firefighters showed reduced gray matter volume in the left superior parietal gyrus and left inferior temporal gyrus. Further, in contrast to HCs, firefighters showed alterations in rsfMRI values in multiple regions, including the fusiform gyrus and cerebellum. @*Conclusion@#Structural and resting-state functional abnormalities in the brain may be useful imaging biomarkers for identifying alterations in trauma-exposed firefighters without PTSD.