Risks of occupational mental disorders in Korean civil servants (2009-18).

BACKGROUND: Previous studies have suggested that firefighters, police officers and civil servants in the education sector, particularly in Western countries, are vulnerable to mental stress and disorders; however, evidence for this association in South Korea is lacking. AIMS: This study aimed to identify whether firefighters, police officers and teachers are at a higher risk for occupational mental health disorders. METHODS: We used workers' compensation claims from civil servants (2009-18). Our target population comprised 46 209 civil servants (9009 civil servants in administrative and technical positions, 23 107 police officers, 4417 firefighters and 8676 civil servants in the educational sector). Occupational and environmental medicine physicians and medical doctors defined and confirmed mental disorders. We conducted Cox proportional hazards regression analyses to evaluate civil servants' risk of occupational mental health disorders. RESULTS: Compared with the civil servants in administrative and technical positions, civil servants in the education sector (hazard ratio [HR] = 2.16; 95% confidence interval [CI]:1.65-2.84) showed a statistically significant increased risk of mental disorders; conversely, firefighters did not (HR = 0.80; 95% CI 0.51-1.27). Police officers had a significantly decreased mental disorder risk compared with civil servants in administrative and technical positions (HR = 0.17; 95% CI 0.11-0.25). CONCLUSIONS: The risk of occupational mental health disorders was higher in civil servants in the education sector but lower in police officers and firefighters than civil servants in administrative and technical positions. Further studies on civil servants' mental health awareness are required to confirm our results.

Tuberculosis infection via the emergency department among inpatients in South Korea: a propensity score matched analysis of the National Inpatient Sample.

BACKGROUND: Emergency departments (EDs) carry a high risk of infectious disease transmission and have also been implicated in tuberculosis (TB) outbreaks. AIM: To determine if patients who visit EDs have an increased risk of TB infection. Using South Korean inpatient sample data (2012), the risk of TB occurrence during 90 days after hospitalization for patients admitted via EDs was compared with that for patients admitted via outpatient clinics. METHODS: The data of the 2012 Health Insurance Review and Assessment Service - National Inpatient Sample were used. TB diagnosis was based on International Classification of Diseases Version 10 [all TB (A15-A19), pulmonary TB (A15-A16) and extrapulmonary TB (A17-A18)]. FINDINGS: After propensity score matching using the demographic and clinical characteristics of the patients, 191,997 patients (64,017 patients admitted via EDs and 127,908 patients admitted via outpatient clinics) were included in this study. There was no significant difference in baseline patient characteristics between the two groups. The percentage of patients with TB admitted via EDs was higher than that of patients admitted via outpatient clinics. The likelihood of active TB occurrence was 30% higher for all TB [hazard ratio (HR) 1.30; 95% confidence interval (CI) 1.12-1.52] and pulmonary TB (HR 1.30; 95% CI 1.10-1.53) in patients admitted via EDs compared with patients admitted via outpatient clinics; this difference was significant. However, no difference in the occurrence of extrapulmonary TB was observed between the two groups. CONCLUSIONS: The likelihood of TB infection was greater in patients admitted via EDs than in patients admitted via outpatient clinics.

Abdominal adiposity intensifies the negative effects of ambient air pollution on lung function in Korean men.

BACKGROUND: Some studies have provided the possibility that adipose tissue may mediate air pollution-induced lung dysfunction. Studies using quantified fat mass data are needed to understand the biological mechanisms between adipocyte and air pollution in lung function. We aimed to investigate whether abdominal adiposity measured by computed tomography (CT) modifies the effects of air pollution on lung function in Korean men. METHODS: A total of 1876 men who visited one of two health checkup centers were recruited for this study. Adiposity traits such as visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and total adipose tissue (TAT) areas were measured by CT. We used the annual mean concentrations of ambient air pollutants including nitrogen dioxide (NO2) and particulate matter with an aerodynamic diameter ⩽10 µm (PM10). RESULTS: Interquartile range (IQR) increase in annual mean concentration of NO2 was significantly associated with a 2.5% lower forced expiratory volume in 1 s (FEV1) and 2.9% lower forced vital capacity (FVC) (both P<0.05). The decrease in lung function was more strongly associated with adiposity traits than with body mass index. In a stratified analysis of adiposity, compared with subjects with low-VAT area (VAT⩽200 cm2), those with high-VAT area (VAT>200 cm2) showed a rapid decrease in FEV1 with each IQR increase in PM10 (ß=-0.0812; 95% confidence interval (CI) =-0.1590, -0.0035) and NO2 (ß=-0.0979; 95% CI=-0.1611, -0.0346). In the high-VAT group, each IQR increase in NO2 content was significantly associated with a 10.6% decrease (ß=-0.1056; 95% CI=-0.1770, -0.0343) in FVC. SAT and TAT areas showed similar patterns. CONCLUSIONS: We report the first finding that abdominal adiposity intensifies the inverse relationship between air pollution and lung function.

Relation of serum vitamin A levels to all-cause and cause-specific mortality among older adults in the NHANES III population.

AIMS: Although studies have suggested that vitamin A is associated with cardiovascular events and mortality, it remains unclear whether low doses or high doses of vitamin A have harmful effects on the cardiovascular system. This study investigated whether serum vitamin A levels are associated with all-cause and cause-specific mortality in US older adults. DATA SYNTHESIS: We analyzed the mortality information for 6069 participants aged 50 years or older who had serum vitamin A data available from the baseline examination. The participants were categorized as having deficient (<30 µg/dL), normal (30-80 µg/dL), or excessive (>80 µg/dL) levels of serum vitamin A, and a multivariate Cox proportional hazards regression analysis was performed on mortality. We found a U-shaped association between serum vitamin A levels and death from all-cause and cause-specific mortality among US adults. Comparing the normal range of serum vitamin A, the hazard ratio with deficient serum vitamin A was 2.9 (95% CI 2.0-4.3) for all-cause mortality, 2.1 (95% CI 1.1-4.1) for cardiovascular-related mortality and 2.5 (95% CI 1.2-5.3) for coronary artery disease-related mortality. Excessive serum vitamin A was associated with a 1.2-fold (95% CI 1.1-1.4) increased risk of all-cause mortality, a 1.4-fold (95% CI 1.2-1.8) increased risk of cardiovascular-related mortality, and a 1.5-fold (95% CI 1.2-2.0) increased risk of coronary artery disease-related mortality compared with the reference group. CONCLUSION: The finding suggests that serum vitamin A levels less than 30 µg/dL or greater than 80 µg/dL levels may indicate a high risk of subsequent mortality.

A prospective study of work stressors and the common cold.

BACKGROUND: Psychological stress is a risk factor for infectious diseases. Although psychological stress at work is considered an important problem for many workers, there is little evidence for the effect of work-related stress on infectious diseases. AIMS: To investigate whether work-related stress affected the occurrence of the common cold in South Korean workers in small- to medium-sized manufacturing companies. METHODS: We conducted a prospective study, involving 1241 workers. At the outset, we collected information regarding sociodemographic and work characteristics. At follow-up after 6 months, we asked subjects whether they had experienced common cold symptoms during the preceding 4 months. RESULTS: Male subjects experiencing stress at the outset were more likely to report having experienced the common cold at follow-up (odds ratios: high job demand group 1.74; 95% CI: 1.28-2.36; insufficient job control 1.42; 95% CI: 1.05-1.93; inadequate social support 1.40; 95% CI: 1.03-1.91). For females, no significant association between work stress and occurrence of the common cold was detected. CONCLUSIONS: Males experiencing work stress in job demand, job control and social support reported an increased occurrence of the common cold at follow-up but this association was not seen in females.