1.Association between relative handgrip strength and glycemic control among male automobile manufacturing workers using vibration tools in South Korea
Dong-Jae SEO ; Hyun Joong KIM ; Yongjin KIM ; Jaewon MUN ; Jong-Han LEEM ; Shin-Goo PARK ; Dong-Wook LEE ; Hwan-Cheol KIM
Annals of Occupational and Environmental Medicine 2026;38(1):e14-
Background:
Although the association between handgrip strength and glycemic control has been reported, studies conducted exclusively within specific occupational groups remain limited. To explore the association between handgrip strength and metabolic health in industrial settings, this study examined the relationship between relative handgrip strength and glycated hemoglobin (HbA1c) among male automobile manufacturing workers using vibration tools in South Korea.
Methods:
Using 66,212 occupational health examination records collected at Inha University Hospital between January 2024 and April 2025, a total of 3,365 workers with HbA1c and handgrip strength measurements were identified. After excluding duplicates (n = 1,536), female workers (n = 2), and records without Hb and estimated glomerular filtration rate, 1,823 male participants were included in the final analysis. Relative handgrip strength was calculated as the maximum value of bilateral grip strength divided by body mass index. Multiple linear regression analyses were conducted to assess the association between relative handgrip strength and HbA1c, adjusting for age, smoking status, alcohol consumption, current hypertension, current dyslipidemia, current hypoglycemic-agents use, family diabetes history, leisure-time physical activity, and resistance exercise.
Results:
Relative handgrip strength was inversely associated with HbA1c levels (B: –0.060; 95% confidence interval [CI]: −0.081 to −0.039; p < 0.001). The association was strongest among normoglycemic participants (B: −0.185; 95% CI: −0.305 to −0.065; p = 0.003). Effect size was reduced but significantly associated among individuals with prediabetes (B: −0.115; 95% CI: −0.180 to −0.050; p < 0.001) and further attenuated to a borderline significance in individuals with diabetes (B: −0.023; 95% CI: −0.050 to 0.003; p = 0.082). These findings indicate that greater muscle strength relative to body size is related to better glycemic control.
Conclusions
Handgrip strength was associated with HbA1c levels in industrial workers. This study suggests that handgrip strength may provide complementary information on metabolic health in occupational settings.
2.Three cases of congenital diseases in the children of female semiconductor workers at a company recognized by the Occupational Disease Adjudication Committee
Chandu KIM ; Hoekyeong SEO ; Jihyung CHOI ; Younghwa CHOI ; Yongjin KIM ; Kyung-Eun LEE ; Shinhee YE
Annals of Occupational and Environmental Medicine 2025;37(1):e9-
Background:
In August 2021, three female semiconductor workers applied for occupational disease compensation due to congenital diseases diagnosed in their children: patient A (immunoglobulin A nephropathy, vesicoureteral reflux, renal agenesis), patient B (renal agenesis, esophageal atresia with tracheoesophageal fistula), and patient C (congenital megacolon). The Occupational Safety and Health Research Institute (OSHRI) initially assessed the relatedness of these conditions to occupational exposure as low. However, the Occupational Disease Adjudication Committee of the Korea Workers’ Compensation and Welfare Service (KWCWS) overturned this assessment, officially recognizing these cases as occupational diseases in March 2024—the first such recognition in South Korea.Case presentation: The mother of Patient A worked in optical processes for 9 years, the mother of patient B worked in diffusion processes for 10 years, and the mother of patient C worked in molding and inspection processes for 7 years. Their jobs involved exposure to benzene, organic solvents, pyrolysis products, ionizing radiation, and X-rays. All three women continued working during pregnancy, and none had a family history of related illnesses.
Conclusions
OSHRI estimated that the occupational exposure levels of these workers were low and noted insufficient reproductive research focused on congenital anomalies in the Korean semiconductor industry before 2010. However, KWCWS cited frequent miscarriages among female semiconductor workers as indirect evidence of an increased risk of congenital anomalies. KWCWS ultimately concluded that substantial evidence supports an association between occupational exposure and congenital diseases in the children of female semiconductor workers. This case series highlights a landmark recognition of occupational disease related to congenital anomalies in the semiconductor industry, emphasizing the need for further reproductive health research and improved worker protections.
3.Recognized cases of amyotrophic lateral sclerosis in automobile workers by the Korean Epidemiologic Investigation Evaluation Committee
Yongjin KIM ; Jong-Hyeop O ; Hyungyoel CHO ; Shinhee YE
Annals of Occupational and Environmental Medicine 2024;36(1):e28-
Background:
Three automobile company workers (one from Factory D and two from Factory E) were diagnosed with amyotrophic lateral sclerosis. The Korean Epidemiologic Investigation and Evaluation Committee determined that there is considerable scientific evidence supporting the association between amyotrophic lateral sclerosis and combined exposure to heavy metals, organic solvents, and diesel exhaust at the manufacturing plant. Case presentation: Patient A, who primarily engaged in engine processing and completed vehicle inspection at Factory D, was exposed to considerable amounts of heavy metals and organic solvents during medium- and large-engine processing, welding, and painting for over 23 years. Additionally, the patient was likely exposed to diesel exhaust for 33 years from forklifts delivering engines in the workshop. Patients B and C, who were responsible for engine assembly, ignition testing, and engine shipment at Factory E since around 1990, were exposed to lead and benzene from gasoline during engine ignition tests in the engine department for 15 and 16 years, respectively. They also encountered welding fumes, heavy metals, and organic solvents during welding and painting tasks. In addition, Patients B and C were continuously exposed to diesel exhaust from logistics vehicles on standby during work hours for 25 and 30 years, respectively.
Conclusions
Although the specific level of lead exposure causing amyotrophic lateral sclerosis remains undetermined, numerous studies have consistently reported a relationship between lead exposure and disease development. Limited evidence suggests that exposure to organic solvents and diesel exhaust may increase the risk of amyotrophic lateral sclerosis. Therefore, the Epidemiological Investigation and Evaluation Committee concluded that the three patients’ work-related exposure to heavy metals, organic solvents, and diesel exhaust is significantly supported by scientific evidence as a cause of their amyotrophic lateral sclerosis.
4.Recognized cases of amyotrophic lateral sclerosis in automobile workers by the Korean Epidemiologic Investigation Evaluation Committee
Yongjin KIM ; Jong-Hyeop O ; Hyungyoel CHO ; Shinhee YE
Annals of Occupational and Environmental Medicine 2024;36(1):e28-
Background:
Three automobile company workers (one from Factory D and two from Factory E) were diagnosed with amyotrophic lateral sclerosis. The Korean Epidemiologic Investigation and Evaluation Committee determined that there is considerable scientific evidence supporting the association between amyotrophic lateral sclerosis and combined exposure to heavy metals, organic solvents, and diesel exhaust at the manufacturing plant. Case presentation: Patient A, who primarily engaged in engine processing and completed vehicle inspection at Factory D, was exposed to considerable amounts of heavy metals and organic solvents during medium- and large-engine processing, welding, and painting for over 23 years. Additionally, the patient was likely exposed to diesel exhaust for 33 years from forklifts delivering engines in the workshop. Patients B and C, who were responsible for engine assembly, ignition testing, and engine shipment at Factory E since around 1990, were exposed to lead and benzene from gasoline during engine ignition tests in the engine department for 15 and 16 years, respectively. They also encountered welding fumes, heavy metals, and organic solvents during welding and painting tasks. In addition, Patients B and C were continuously exposed to diesel exhaust from logistics vehicles on standby during work hours for 25 and 30 years, respectively.
Conclusions
Although the specific level of lead exposure causing amyotrophic lateral sclerosis remains undetermined, numerous studies have consistently reported a relationship between lead exposure and disease development. Limited evidence suggests that exposure to organic solvents and diesel exhaust may increase the risk of amyotrophic lateral sclerosis. Therefore, the Epidemiological Investigation and Evaluation Committee concluded that the three patients’ work-related exposure to heavy metals, organic solvents, and diesel exhaust is significantly supported by scientific evidence as a cause of their amyotrophic lateral sclerosis.
5.Recognized cases of amyotrophic lateral sclerosis in automobile workers by the Korean Epidemiologic Investigation Evaluation Committee
Yongjin KIM ; Jong-Hyeop O ; Hyungyoel CHO ; Shinhee YE
Annals of Occupational and Environmental Medicine 2024;36(1):e28-
Background:
Three automobile company workers (one from Factory D and two from Factory E) were diagnosed with amyotrophic lateral sclerosis. The Korean Epidemiologic Investigation and Evaluation Committee determined that there is considerable scientific evidence supporting the association between amyotrophic lateral sclerosis and combined exposure to heavy metals, organic solvents, and diesel exhaust at the manufacturing plant. Case presentation: Patient A, who primarily engaged in engine processing and completed vehicle inspection at Factory D, was exposed to considerable amounts of heavy metals and organic solvents during medium- and large-engine processing, welding, and painting for over 23 years. Additionally, the patient was likely exposed to diesel exhaust for 33 years from forklifts delivering engines in the workshop. Patients B and C, who were responsible for engine assembly, ignition testing, and engine shipment at Factory E since around 1990, were exposed to lead and benzene from gasoline during engine ignition tests in the engine department for 15 and 16 years, respectively. They also encountered welding fumes, heavy metals, and organic solvents during welding and painting tasks. In addition, Patients B and C were continuously exposed to diesel exhaust from logistics vehicles on standby during work hours for 25 and 30 years, respectively.
Conclusions
Although the specific level of lead exposure causing amyotrophic lateral sclerosis remains undetermined, numerous studies have consistently reported a relationship between lead exposure and disease development. Limited evidence suggests that exposure to organic solvents and diesel exhaust may increase the risk of amyotrophic lateral sclerosis. Therefore, the Epidemiological Investigation and Evaluation Committee concluded that the three patients’ work-related exposure to heavy metals, organic solvents, and diesel exhaust is significantly supported by scientific evidence as a cause of their amyotrophic lateral sclerosis.
6.Health Effects of Microplastic Exposures: Current Issues and Perspectives in South Korea
Yongjin LEE ; Jaelim CHO ; Jungwoo SOHN ; Changsoo KIM
Yonsei Medical Journal 2023;64(5):301-308
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.
7.Intra-sinus rigid fixation of a resorbable barrier membrane to repair a large perforation of the sinus membrane: a technical note
Won-Jun JOUNG ; Seo-Hyoung YUN ; Yongjin KIM ; Yong-Seok CHO ; Won-Woo LEE ; Jin-Won SEO ; Marco TALLARICO ; Kyung-Gyun HWANG ; Chang-Joo PARK
Journal of the Korean Association of Oral and Maxillofacial Surgeons 2023;49(5):297-303
A resorbable barrier membrane is commonly used for the repair of perforated sinus membranes during sinus lifting surgeries. However, repairing largescale perforations poses challenges for clinicians as the protection and isolation of graft material remain uncertain. With this technique, we aimed to prevent graft material loss and subsequent sinus-related complications using intra-sinus rigid fixation of the resorbable barrier membrane in cases with a large perforation of the sinus membrane.
8.Treatment Results of Reamed Exchange Nailing in Aseptic Nonunion of Tibial Shaft Fracture
Yongjin CHO ; Jun Young LEE ; Jehong RYU ; Hyoung Tae KIM ; Jong Jin MOON
Journal of the Korean Fracture Society 2023;36(4):125-132
Purpose:
Intramedullary nailing is used widely for treating tibial diaphysis fractures because of its relatively rigid internal fixation, which allows weight bearing, resulting in rapid bone healing and functional recovery. This study evaluated the results of exchange nailing in treating aseptic nonunion of tibial shaft fractures.
Materials and Methods:
From November 2015 to December 2021, a retrospective study was conducted on patients who had undergone intramedullary nailing for tibial diaphysis fractures. Among them, this study focused on patients diagnosed with nonunion and who underwent exchange nailing. Twenty patients with a minimum follow-up period of at least 12 months were included in the study.
Results:
The mean ages of patients were 60 years (range, 30-79 years). Of the 20 cases in which exchange nailing was performed, bone union was achieved in 18 cases (90.0%), and the mean period was 23 weeks (range, 14-46 weeks). Among the 18 cases of bone union, one case exhibited delayed union and achieved union without additional treatment after 46 weeks, while two cases of nonunion failed to achieve union and were lost to follow-up until the final assessment.
Conclusion
Reamed exchange nailing performed on aseptic nonunion after intramedullary nailing for tibial diaphysis fractures had satisfactory clinical outcomes.
9.The usefulness of trabecular bone score in patients with ankylosing spondylitis
Seoung Wan NAM ; Yoon-Kyoung SUNG ; Dam KIM ; Soo-Kyung CHO ; Yoonah SONG ; Yun Young CHOI ; Yongjin SIM ; Tae-Hwan KIM
The Korean Journal of Internal Medicine 2021;36(5):1211-1220
Background:
s/Aims: This study was performed to reveal the usefulness of the trabecular bone score (TBS) in assessing bone strength in patients with ankylosing spondylitis (AS) in comparison with dual-energy X-ray absorptiometry (DXA) methods.
Methods:
A total of 215 AS patients (75.8% male) were enrolled from a single university hospital in Korea. Demographic and clinical information were assessed. Patients completed X-rays of the cervical and lumbar spine (L-spine), and spinal ankyloses were quantified using the modified Stoke AS Spine Score (mSASSS). Hip, anteroposterior and lateral L-spine bone mineral density (BMD) and TBS were assessed by DXA methods. Clinical characteristics and bone strength measurement results were compared between male and female AS patients. The accuracy of each bone strength evaluation method in predicting Fracture Risk Assessment Tool (FRAX) scores indicating moderate or higher fracture risk was compared by receiver operating characteristic curves in patients aged ≥ 40 years. Correlations between each bone strength measurement method and mSASSS were examined.
Results:
Male patients showed higher mSASSS and less prevalent peripheral joint involvement compared to female patients (p < 0.05). TBS, hip BMD, and L-spine lateral BMD showed comparably high areas under the curve (AUCs) for predicting FRAX-major osteoporotic fractures (MOF) ≥ 10% (AUC ranged 0.72 to 0.76). TBS negatively correlated with mSASSS in both male and female patients (p < 0.01).
Conclusions
TBS could predict the risk of MOF and is not influenced by spinal osteoproliferation in AS patients, even in those with advanced spinal changes.
10.The usefulness of trabecular bone score in patients with ankylosing spondylitis
Seoung Wan NAM ; Yoon-Kyoung SUNG ; Dam KIM ; Soo-Kyung CHO ; Yoonah SONG ; Yun Young CHOI ; Yongjin SIM ; Tae-Hwan KIM
The Korean Journal of Internal Medicine 2021;36(5):1211-1220
Background:
s/Aims: This study was performed to reveal the usefulness of the trabecular bone score (TBS) in assessing bone strength in patients with ankylosing spondylitis (AS) in comparison with dual-energy X-ray absorptiometry (DXA) methods.
Methods:
A total of 215 AS patients (75.8% male) were enrolled from a single university hospital in Korea. Demographic and clinical information were assessed. Patients completed X-rays of the cervical and lumbar spine (L-spine), and spinal ankyloses were quantified using the modified Stoke AS Spine Score (mSASSS). Hip, anteroposterior and lateral L-spine bone mineral density (BMD) and TBS were assessed by DXA methods. Clinical characteristics and bone strength measurement results were compared between male and female AS patients. The accuracy of each bone strength evaluation method in predicting Fracture Risk Assessment Tool (FRAX) scores indicating moderate or higher fracture risk was compared by receiver operating characteristic curves in patients aged ≥ 40 years. Correlations between each bone strength measurement method and mSASSS were examined.
Results:
Male patients showed higher mSASSS and less prevalent peripheral joint involvement compared to female patients (p < 0.05). TBS, hip BMD, and L-spine lateral BMD showed comparably high areas under the curve (AUCs) for predicting FRAX-major osteoporotic fractures (MOF) ≥ 10% (AUC ranged 0.72 to 0.76). TBS negatively correlated with mSASSS in both male and female patients (p < 0.01).
Conclusions
TBS could predict the risk of MOF and is not influenced by spinal osteoproliferation in AS patients, even in those with advanced spinal changes.

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