Coronary Artery Calcification on Low-Dose Lung Cancer Screening CT in South Korea: Visual and Artificial Intelligence-Based Assessment and Association With Cardiovascular Events.

Background: Coronary artery calcification (CAC) on lung cancer screening low-dose chest CT (LDCT) is a cardiovascular risk marker. South Korea was the first Asian country to initiate a national LDCT lung cancer screening program, although CAC-related outcomes are poorly explored. Objective: To evaluate CAC prevalence and severity using visual analysis and artificial intelligence (AI) methods and to characterize CAC's association with major adverse cardiovascular events (MACEs) in patients undergoing LDCT in Korea's national lung cancer screening program. Methods: This retrospective study included 1002 patients (mean age, 62.4±5.4 years; 994 men, 8 women) who underwent LDCT at two Korean medical centers between April 2017 and May 2023 as part of Korea's national lung cancer screening program. Two radiologists independently assessed CAC presence and severity using visual analysis, consulting a third radiologist to resolve differences. Two AI software applications were also used to assess CAC presence and severity. MACE occurrences were identified by EMR review. Results: Interreader agreement for CAC presence and severity, expressed as kappa, were 0.793 and 0.671, respectively. CAC prevalence was 53.4% by consensus visual assessment, 56.6% by AI software I, and 60.1% by AI software II. CAC severity was mild, moderate, and severe by consensus visual analysis in 28.0%, 10.3% and 15.1%; by AI software I in 39.9%, 14.0%, and 6.2%; and by AI software II in 34.9%, 14.3%, and 7.3%. MACE occurred in 36 of 625 (5.6%) patients with follow-up after LDCT (median, 1108 days). MACE incidence in patients with no, mild, moderate, and severe CAC, for consensus visual analysis was 1.1%, 5.0%, 2.9%, and 8.6% (p<.001); for AI software I was 1.3%, 3.0%, 7.9%, and 11.3% (p<.001); and for AI software II was 1.2%, 5.0%, 7.7%, and 9.6% (p<.001) Conclusion: For Korea's national lung cancer screening program, MACE occurrence increased significantly with increasing CAC severity, whether assessed by visual analysis or AI software. The study is limited by the large sex imbalance for Korea's national lung cancer screening program. Clinical Impact: The findings provide reference data for healthcare practitioners engaged in developing and overseeing national lung cancer screening programs, highlighting the importance of routine CAC evaluation.

Association between Weight Change and Incidence of Dyslipidemia in Young Adults: A Retrospective Cohort Study of Korean Male Soldiers.

Background: Recent lifestyle changes have increased the prevalence of dyslipidemia in Korea. Young men are known to have a low awareness of dyslipidemia and a lack of motivation to maintain their weight. However, the association between weight change and dyslipidemia in young adults has not been thoroughly examined. Methods: Data from the Armed Forces Medical Command Defense Medical Information System database were used. In this study, 15,068 soldiers who underwent private and corporal health examinations between May 2020 and April 2022 were included. The difference in weights between the two different health examinations was used to quantify weight change. Four components of the lipid profile were used to assess dyslipidemia during the corporal health examination. Results: After adjusting for relevant covariates, weight gain was associated with increased risk of dyslipidemia (adjusted odds ratio [OR], 1.38 [95% confidence interval, CI, 1.15 to 1.64] for the 5% to 10% weight gain group; and OR, 2.02 [95% CI, 1.59 to 2.55] for the ≥10% weight gain group), whereas weight loss was associated with decreased risk (adjusted OR, 0.82 [95% CI, 0.68 to 0.98] for the 5% to 10% weight loss group; and OR, 0.38 [95% CI, 0.27 to 0.53] for the ≥10% weight loss group). In subgroup analysis based on the participants' baseline body mass index, smoking status, regular exercise habits, and hypertension status, there were no significant differences between the subgroups. Conclusion: Weight change was associated with dyslipidemia in Korean male soldiers. The findings suggest that limiting weight gain in young adults by encouraging a healthy lifestyle may help prevent dyslipidemia.

Twenty-two-year incidence trend of urological cancers in the Republic of Korea: 1999-2020.

PURPOSE: Cancer is a disease with high social costs, and policymaking through accurate statistics is very important. This study presents the national cancer statistics on the incidence of urological cancers in the Republic of Korea over 22 years, from 1999 to 2020. MATERIALS AND METHODS: Through the Korean Statistical Information Service, data on the incidence of urological cancers by sex and age in each year was obtained. For each urological cancer, the number of cases, crude incidence rate (CIR), and age-standardized incidence rate (ASR) were calculated, and the statistical trends were confirmed by joinpoint regression analysis. RESULTS: Urological cancers, which have increased ASR over 22 years, are as follows: prostate cancer (average annual percent change [AAPC]=6.72%, p-trend<0.05), testicular cancer (AAPC=5.26%, p-trend<0.05), ureter cancer (AAPC=4.16%, p-trend<0.05), kidney cancer (AAPC=4.14%, p-trend<0.05), renal pelvis cancer (AAPC=3.86%, p-trend<0.05), and total urological cancer (AAPC=4.37%, p-trend<0.05). Urological cancers, which has decreased ASR over 22 years, are as follows: penile cancer (AAPC=-2.93%, p-trend<0.05) and bladder cancer (AAPC=-0.31%, p-trend<0.05). CONCLUSIONS: It was confirmed that the ASR of all urological cancers increased for 22 years, except for bladder and penile cancer. With the aging of the population, the CIR increased for all urological cancers. This study will serve as basic data for future research and policy decisions.

Association between Occupational Noise Exposure and Insomnia among Night-Shift Production Workers: A 4-Year Follow-up Study.

Objectives: This study aimed to investigate whether occupational noise exposure is a risk factor for insomnia among male night-shift production workers. Methods: This study followed 623 male night-shift production workers at a tire manufacturing factory without insomnia for 4 years. Insomnia was evaluated based on the insomnia severity index at baseline and at 4-year follow-up. A score of ≥15 was defined as insomnia. The higher occupational noise exposure group was defined as those individuals exposed to 8-hour time-weighted-average noise above 80 dB (A). Results: Participants' mean age was 46.3 ± 5.6 years. Of the 623 participants, 362 (58.1%) were in the higher occupational noise exposure group. At 4-year follow-up, insomnia occurred in 3.2% (n = 20) of the participants. In a multiple logistic regression analysis, the odds ratio of insomnia was 3.36 (95% confidence interval 1.083-10.405, P = 0.036) in the higher occupational noise exposure group when compared with the lower noise exposure group after adjusting for confounders. Conclusion: Our findings suggested that occupational noise exposure affected insomnia in male night-shift production workers. To prevent insomnia, efforts are required to reduce workplace noise exposure levels. Alternatively, moving to a less noisy work environment should be considered for workers with severe insomnia.

Changes in the Health Indicators of Hospital Medical Residents During the Four-Year Training Period in Korea.

BACKGROUND: In South Korea, the legal maximum working hours per week for medical residents is 88 hours, which are longer than those for other occupations, and the intensity of the workload is also remarkably high. Long working hours and job-related stress can worsen the health status of residents. This study aimed to analyze the four-year annual health checkup (AHC) data of residents to identify changes in their health indicators. METHODS: This study included 457 male residents who received 4 years of training at a university hospital. They underwent an AHC every year during the training period. Changes in health indicators and related factors over the 4 years were investigated. RESULTS: Body mass indices (BMI), blood pressures (BPs), liver function test (LFT) results, and total cholesterol (TC) levels were significantly worsened during the training period. The increases were the highest in the early training years, between the 2nd and 1st AHC. The working hours of the fourth-year residents were the shortest and showed low smoking and drinking rates and high regular exercise rates. On comparing by department, surgical residents showed the highest increases in BMI, diastolic BP, and fasting blood glucose (FBG), LFT enzyme, and TC levels during the training period, compared to residents from the medical and clinical support departments. Residents who were working ≥ 80 hours showed significantly higher FBG and LFT enzyme levels than those working < 80 hours. CONCLUSION: This study is meaningful as it is the first study in Korea to investigate the changes in the health of residents through objective health indicators. The possibility of the 4-year training period adversely affecting the health of residents was confirmed. Health indicators were significantly worsened, especially in the early training period, in surgical residents, and in residents who worked for long hours. Efforts are needed to restrict long working hours and distribute workload during the 4-year training period.

Occupational dose and associated factors during transarterial chemoembolization of hepatocellular carcinoma using real-time dosimetry: A simple way to reduce radiation exposure.

ABSTRACT: Transarterial chemoembolization is the standard treatment option for intermediate-stage hepatocellular carcinoma (HCC). However, during the interventional procedure, occupational radiation protection is compromised. The use of real-time radiation dosimetry could provide instantaneous radiation doses. This study aimed to evaluate the occupational dose of the medical staff using a real-time radiation dosimeter during transarterial chemoembolization (TACE) for HCC, and to investigate factors affecting the radiation exposure dose.This retrospective observational study included 70 patients (mean age: 66 years; age range: 38-88 years; male: female = 59: 11) who underwent TACE using real-time radiation dosimetry systems between August 2018 and February 2019. Radiation exposure doses of operators, assistants, and technicians were evaluated. Patients' clinical, imaging, and procedural information was analyzed.The mean dose-area product (DAP) and fluoroscopy time during TACE were 66.72 ±â€Š55.14 Gycm2 and 12.03 ±â€Š5.95 minutes, respectively. The mean radiation exposure doses were 24.8 ±â€Š19.5, 2.0 ±â€Š2.2, and 1.65 ±â€Š2.0 µSv for operators, assistants, and technicians, respectively. The radiation exposure of the operators was significantly higher than that of the assistants or technicians (P < .001). The perpendicular position of the adjustable upper-body lead protector (AULP) on the table was one factor reducing in the radiation exposure of the assistants (P < .001) and technicians (P = .040). The DAP was a risk factor for the radiation exposure of the operators (P = .003) and technicians (P < .001).Occupational doses during TACE are affected by DAP and AULP positioning. Placing the AULP in the perpendicular position during fluoroscopy could be a simple and effective way to reduce the radiation exposure of the staff. As the occupational dose influencing factors vary by region or institution, further study is needed.

Twenty-year incidence trend of hematologic malignancies in the Republic of Korea: 1999-2018.

BACKGROUND: In this study, we presented the national cancer statistics on the incidence of hematologic malignancies in the Republic of Korea (ROK) over a period of 20 years, from 1999 to 2018. METHODS: We obtained data on the incidence of hematologic malignancies using the Korean Statistical Information Service (KOSIS). For each hematologic malignancy, the number of cases, crude incidence rate, and age-standardized incidence rate were calculated, and the statistical trends were confirmed by Poisson regression and Joinpoint regression analysis. RESULTS: All the investigated hematologic malignancies showed a statistically significant increase in incidence over 20 years. The 20-year trend of the age-standardized incidence rate was as follows: non-Hodgkin lymphoma [average annual percent change (AAPC)=2.26%, P-trend <0.05], leukemia (AAPC=0.94%, P-trend <0.05), myeloid leukemia (AAPC=1.44%, P-trend <0.05), multiple myeloma (AAPC=3.05%, P-trend <0.05), myeloproliferative disorders (AAPC=9.87%, P-trend <0.05), myelodysplastic syndrome (AAPC=7.59%, P-trend <0.05), malignant immunoproliferative diseases (AAPC=11.82%, P-trend <0.05), lymphoid leukemia (AAPC=2.21%, P-trend <0.05), and Hodgkin lymphoma (AAPC=4.04%, P<0.05). CONCLUSION: It was confirmed that the incidence of hematologic malignancies has increased significantly in the ROK over the past 20 years. This study can be used as foundational data source for future studies. In addition, it can aid in the necessary actions of predicting future incidences and establishing future healthcare policies.

Associations between Blood Lead Levels and Coronary Artery Stenosis Measured Using Coronary Computed Tomography Angiography.

BACKGROUND: Lead exposure is a risk factor for increased blood pressure and cardiovascular disease, even when blood lead levels (BLLs) are within the normal range. OBJECTIVE: This study aimed to investigate the association between BLL and coronary artery stenosis (CAS) in asymptomatic adults using 128-slice dual-source coronary computed tomography (CT) angiography. METHODS: We analyzed medical records data from 2,193 adults (1,461 men and 732 women) who elected to complete a screening health examination, coronary CT angiography, and BLL measurement during 2011-2018 and had no history of CAS symptoms, cardiovascular disease, or occupational exposure to lead. Logistic regression models were used to estimate associations between moderate-to-severe CAS (≥25% stenosis) and a 1-µg/dL increase in blood lead, with and without adjustment for age, sex, hypertension, diabetes mellitus, dyslipidemia, body mass index, regular exercise, smoking status, and alcohol drinking. RESULTS: BLLs ranged from 0.12 to 10.14µg/dL, with an arithmetic mean of 2.71±1.26µg/dL. The arithmetic mean was higher for men than for women (2.98±1.26µg/dL vs. 2.18±1.08µg/dL, p<0.001) and higher in the moderate-to-severe CAS group than in the no-CAS or <25% stenosis group (3.02±1.44µg/dL vs. 2.67±1.23µg/dL, p<0.001). Moderate-to-severe CAS was significantly associated with BLL before and after adjustment, with an adjusted odds ratio for a 1-µg/dL increase in BLL of 1.14 (95% CI: 1.02, 1.26), p=0.017. CONCLUSIONS: BLL was positively associated with the prevalence of moderate-to-severe CAS in Korean adults who completed an elective screening examination for early cardiovascular disease, 94% of whom had a BLL of <5µg/dL. More efforts and a strict health policy are needed to further reduce BLLs in the general population. https://doi.org/10.1289/EHP7351.

Effects of Exposure to Lead and Cadmium on Health of Inhabitants of Abandoned Metal Mine Area in Korea.

People living near abandoned mines are at increased risk of exposure to toxic metals. We surveyed 4500 inhabitants with the mean age of 68.5 years old (male: 1768, female: 2732) living near 104 abandoned metal mines from 2013 to 2017 (the 2nd phase health survey in Korea). We conducted personal interviews, blood and urine sampling, and analyzed the concentrations of lead (Pb) and cadmium (Cd) in whole blood and Cd in urine using a graphite furnace atomic absorption spectrometer. The geometric means of blood Pb, blood Cd, and urine Cd were 2.27 µg/dL, 1.42 µg/L, and 1.66 µg/g creatinine, respectively. The level of metal exposure was lower than that reported from the first phase health survey in Korea (2008‒2011) but was higher than in the general population of Korea. Blood Pb was higher in males while blood Cd and urine Cd were significantly higher in females. Blood Pb was highest in the 40‒59 age group, while blood and urine Cd levels continuously increased until age 80 or older. The Cd levels in blood and urine were affected by consumption of locally produced rice and duration of residence near abandoned mines. Furthermore, negative correlations were observed between blood Pb and blood and urine Cd levels. Additionally, 252 of the 4500 subjects exceeded the thresholds of blood Cd or urine Cd levels. Together, these findings suggest that Cd has more sustainable and adverse health effects on the abandoned mine inhabitants, who are mostly aged. Therefore, continuous biomonitoring and risk assessment to environmental health risks are necessary for environmental pollution control and health promotion.

Blood lead level and Helicobacter pylori infection in a healthy population: A cross-sectional study.

The aim of this study was to investigate whether elevated blood lead level (BLL) is a risk factor for Helicobacter pylori infection. Upper gastrointestinal endoscopy was performed on 2,625 subjects who visited a university hospital for general health examination. H. pylori infection was detected using histologic examination with Giemsa staining, and BLLs were measured. The mean BLL was 2.83 ± 1.31 µg/dL. The prevalence of H. pylori infection was 27.8%. The BLL was significantly higher in the H. pylori infection-positive group compared to the non-infected group (2.96 ± 1.33 µg/dL vs. 2.78 ± 1.30 µg/dL, p < 0.001), which remained significant after adjusting for other confounders. H. pylori infection significantly increased as the BLL increased (OR: 1.143, 95% CI 1.068-1.223). We found a relationship between BLL elevation and H. pylori infection rate.

Night shiftwork and prostate-specific antigen level in a tire manufacturing factory.

BACKGROUND: Recent studies suggest that night shiftwork may increase the risk of prostate cancer and elevated serum prostate-specific antigen (PSA) level. The purpose of this study was to verify whether rotating night shiftwork affects serum PSA level. METHODS: This study included 3,195 male production workers who work in a large tire manufacturing factory. Serum PSA levels were measured and the data on related factors were obtained. RESULTS: The mean serum PSA level was 0.98 ± 0.79 ng/mL. PSA levels were significantly lower in the younger age group, the obese group, and regular exercise group. PSA levels were lower in night shift workers (n = 2,832) compared to day workers (n = 363), but the difference was not statistically significant. CONCLUSIONS: Unlike previous studies, we did not find any evidence that night shiftwork results in an increase in serum PSA levels. Further research and consistent results are needed to elucidate the association between night shiftwork and the effect on the prostate.

Acute radiation syndrome in a non-destructive testing worker: a case report.

BACKGROUND: In Korea, there were repeated radiation exposure accidents among non-destructive testing workers. Most of the cases involved local injury, such as radiation burns or hematopoietic cancer. Herein, we report a case of acute radiation syndrome caused by short periods of high exposure to ionizing radiation. CASE PRESENTATION: In January 2017, Korea Information System on Occupational Exposure (KISOE) found that a 31-year-old man who had worked in a non-destructive testing company had been overexposed to radiation. The patient complained of symptoms of anorexia, general weakness, prostration, and mild dizziness for several days. He was anemic. The venous injection areas had bruises and bleeding tendency. Blood and bone marrow testing showed pancytopenia and the patient was diagnosed with acute radiation syndrome (white blood cells: 1400/cubic mm, hemoglobin: 7.1 g/dL, platelets: 14000/cubic mm). He was immediately prohibited from working and blood transfusion was commenced. The patient's radiation exposure dose was over 1.4 Gy (95% confidence limits: 1.1-1.6) in lymphocyte depletion kinetics. It was revealed that the patient had been performing non-destructive tests without radiation shielding when working in high places of the large pipe surface. CONCLUSIONS: Exposure prevention is clearly possible in radiation-exposed workers. Strict legal amendments to safety procedures are essential to prevent repeated radiation exposure accidents.

Selection of Surgical Approach for Trigonal Meningiomas in Consideration of Visual Outcome.

OBJECTIVES: We report the surgical outcome of trigonal meningiomas through 3 different approaches with attention to visual outcomes. METHODS: Between 1994 and 2017, 23 patients underwent resection of trigonal meningiomas. We performed tumor removal using 3 different surgical approaches through the superior parietal lobule, middle temporal gyrus (MTG), and modified MTG. The patients were retrospectively identified, and surgical results including visual outcome were analyzed. RESULTS: Twenty-three patients with a mean age of 45 years formed the study group. The most common symptom and sign were headache (N = 14, 60.9%) and visual disturbance (N = 6, 26.1%). All patients underwent surgical resection, 6 via a translateral approach through MTG, 8 via a translateral approach through modified MTG, and 9 via a transparietal approach through the superior parietal lobule (SPL). Gross total resection was achieved in all patients. We found that visual preservation rate was 25% (1/4) in the MTG group, 62.5% (5/8) in the modified MTG group, and 100% (7/7) in the SPL group, respectively (P = 0.044). Permanent complication rate was 50% (3/6) in the MTG group, 50% (n = 4/8) in the modified MTG group, and 11.1% (n = 1/9) in the SPL group. CONCLUSIONS: The superior parietal lobule approach is a safe and applicable procedure with a great visual preservation and an acceptable risk of morbidity for trigonal meningiomas when there is a chance of visual recovery or preservation.

Insomnia and hearing impairment among occupational noise exposed male workers.

BACKGROUND: The aim of this study was to investigate the association between insomnia and hearing impairment among workers exposed to occupational noise. METHODS: This study included 809 male workers exposed to occupational noise. The participants underwent audiometric testing, and their insomnia was examined based on the Insomnia Severity Index test. Hearing impairment was defined as hearing threshold >25 dB hearing level in the range of 1-4 kHz. RESULTS: According to analysis of covariance, it was observed that pure tone audiometry thresholds at 1-2 kHz in the right ear and at 1 kHz in the left ear were significantly higher among workers with insomnia compared to those with no insomnia. Multiple logistic regression analysis of insomnia for hearing impairments was performed, which showed the odds ratio was 1.806 (95% confidence intervals: 1.022-3.188, p = 0.042) after adjustment for age, working period, noise level, snoring, use of protection devices, diabetes mellitus, hypertension, smoking, alcohol consumption, regular exercise, waist circumference, total cholesterol, triglyceride and high density lipoprotein cholesterol. CONCLUSION: Insomnia could be associated with hearing impairment in workers who are exposed to occupational noise. Additionally, insomnia may be associated with decreased hearing at low frequencies. Especially, more efforts are required to improve the quality of sleep for workers who are exposed to loud occupational noise. Further well- designed prospective studies are needed to clarify the relationship between insomnia and hearing impairment.

Comparison of anxiety and depression status between office and manufacturing job employees in a large manufacturing company: a cross sectional study.

BACKGROUND: The aim of this study was to investigate whether type of work is associated with anxiety and depression using the Hospital Anxiety and Depression Scale (HADS). Additionally, we investigated the impact of number of working hours on anxiety and depression. METHODS: A total of 1774 workers participated and completed the HADS to determine their levels of anxiety and depression. All subjects were employed at one of two manufacturing plants for the same company. Of all participants, 222 were employed in office jobs and 1552 in manufacturing jobs. RESULTS: Results of multivariate logistic regression analysis including age, sex, body mass index, smoking status, alcohol consumption, regular exercise, factory region, and working hours, indicated that employment in an office job was associated with a 2.17-fold increase in the odds of anxiety compared to a manufacturing job (odds ratio [OR] = 2.17; 95 % confidence interval [CI], 1.24-3.80). Office jobs were also associated with a 1.94-fold increase in the odds of depression (OR = 1.94; 95 % CI, 1.34-2.82). In addition, number of hours worked was significantly associated with depression, and working hours significantly modified the effect of office job employment on the risk of depression. CONCLUSIONS: Office job workers had higher levels of anxiety and depression than those working in manufacturing jobs. Our findings suggest that occupational physicians should consider the organizational risks faced by office job employees, and consider the differences in psychological health between office and manufacturing job workers when implementing interventions.

Occupational Lead Exposure from Indoor Firing Ranges in Korea.

Military personnel often use ammunitions that contain lead. The present study aimed to identify the risks for lead exposure and lead poisoning among workers at indoor firing ranges. A special health examination, including blood lead level (BLL) testing, was performed for all 120 workers at the indoor firing ranges of the Republic of Korea's Air Force, Navy, and Armed Forces Athletic Corps. The overall mean BLL was 11.3 ± 9.4 µg/dL (range: 2.0-64.0 µg/dL). The arithmetic mean of the BLL for professional shooters belong to Armed Forces Athletic Corps was 14.0 ± 8.3 µg/dL, while those of shooting range managers and shooting range supervisors were 13.8 ± 11.1 µg/dL and 6.4 ± 3.1 µg/dL, respectively. One individual had a BLL of 64 µg/dL, and ultimately completed chelation treatment (with CaNa2-ethylenediaminetetraacetic acid) without any adverse effects. These findings indicate that indoor firing range workers are exposed to elevated levels of lead. Therefore, when constructing an indoor firing range, a specialist should be engaged to design and assess the ventilation system; and safety guidelines regarding ammunition and waste handling must be mandatory. Moreover, workplace environmental monitoring should be implemented for indoor firing ranges, and the workers should undergo regularly scheduled special health examinations.

Coronary artery atherosclerosis associated with shift work in chemical plant workers by using coronary CT angiography.

OBJECTIVES: The aim of this study was to investigate whether shift work is related to elevated risk of coronary artery disease (CAD) by determining the coronary artery calcium (CAC) score and the presence of coronary artery stenosis by using coronary artery CT angiography (CCTA). METHODS: In this study, 110 male workers participated and underwent a CCTA examination for CAC scoring, which represents coronary artery plaque, and were evaluated for luminal stenosis. All of the participants were working in the same chemical plant, of whom 70 worked day shifts and 40 worked rotating shifts. RESULTS: In a multivariate logistic regression analysis, including age, smoking status, alcohol consumption, regular exercise and waist circumference, shift work was associated with a 2.89-fold increase in the odds of developing coronary plaque compared with day work (OR, 2.89; 95% CI 1.07 to 7.82). The association between shift work and coronary plaque was strong after adjustment for age, low-density lipoprotein cholesterol, hypertension and diabetes mellitus (OR, 2.92; 95% CI 1.02 to 8.33). In addition, the number of years of shift work employment was associated with coronary plaque. However, no association was found between shift work and coronary artery stenosis. CONCLUSIONS: Shift work could induce CAD onset via the atherosclerotic process, and shift work employment duration was associated with an increased risk of atherosclerosis in male workers.

Serum prostate-specific antigen levels and type of work in tire manufacturing workers.

OBJECTIVES: This study measures serum prostate-specific antigen (PSA) levels in tire-manufacturing workers, and attempts to find occupational or non-occupational factors that related to their PSA levels. METHODS: A total of 1,958 healthy male workers (1,699 were production workers and 259 were office workers) took PSA measurement for analysis. RESULTS: After adjusting for age, body mass index, hypertension, regular exercise, alcohol drinking and smoking, which were significantly related to serum PSA levels or known related factors of serum PSA levels, the geometric mean PSA levels were significantly high in the office workers (p = 0.017), the older age group (p < 0.001), the group with hypertension (p = 0.046) and the group of individuals that do not exercise regularly (p = 0.015) and the office workers were more likely to have a serum PSA level of ≥4.0 (OR 7.73, 95% CI: 2.78-21.46) or 2.5 ng/mL (OR 2.74, 95% CI: 1.49-5.08). After stratifying by age and adjusting aforementioned covariates, office workers 50 years of age and older had the significantly higher geometric mean PSA levels (p = 0.017) and were more likely to have a serum PSA level of ≥4.0 ng/mL (OR 12.90, 95% CI: 3.65-45.64) or 2.5 ng/mL (OR 3.90, 95% CI: 1.64-9.25) than production workers 50 years of age and older. CONCLUSIONS: This study showed that serum PSA levels were significantly higher among the group with hypertension or the group of individuals that did not exercise regularly or group of office workers who were considered to have lesser physical activities.