Cancer Incidence Among Air Transportation Industry Workers Using the National Cohort Study of Korea

Cancer risk among air transportation industry workers in Korea: a national health registry-based study

BACKGROUND

Flight attendants face various risk factors in their working environments, particularly occupational exposure to cosmic radiation. This study aimed to assess cancer risk among air transportation industry workers, including flight attendants, in Korea by constructing a cohort using national health registry-based data and analyzing cancer incidence risk.

METHODS

We used the Korea National Health Insurance Service database from 2002 to 2021 to construct a cohort of 37,011 workers in the air transportation industry. Cancer incidence was defined using the tenth version of the International Classification of Diseases. We calculated the age- and sex-specific standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) by applying the cancer incidence rate of the general population between 2002 and 2019.

RESULTS

Approximately 5% of the cohort developed cancer. Overall, the cancer incidence in the cohort was similar to or lower than that of the general population, with the SIRs for all cancers being lower. However, significantly higher SIRs were observed for nasopharyngeal cancer (SIR, 3.21; 95% CI, 1.71-5.48) and non-Hodgkin lymphoma (SIR, 1.57; 95% CI, 1.02-2.32) in male workers and breast and genital cancer (SIR, 1.51; 95% CI, 1.34-1.70) and thyroid cancer (SIR, 1.25; 95% CI, 1.05-1.47) in female workers.

CONCLUSIONS

The lower overall cancer incidence among air transportation industry workers observed in this study could indicate the "healthy worker effect"; however, the incidences of certain cancers were higher than those in the general population. Given that these workers are exposed to multiple occupational and lifestyle-related risk factors, including cosmic radiation, further studies are necessary to determine radiation-induced cancer risk while considering potential confounding factors.

Cancer Incidence in Korean Healthcare Workers in Hospitals

Objectives: Healthcare workers in hospitals (HHCWs), a notably increasing workforce, face various occupational hazards. A high incidence of cancer among HHCWs has been observed; however, the cancer incidence status among HHCWs in South Korea is yet to be studied. This study aimed to assess cancer incidence among HHCWs in South Korea. Methods: We constructed a retrospective cohort of HHCWs using National Health Insurance claims data, including cancer incidence status and vital status, from 2007 to 2015. Those who had worked in hospitals for at least three years were defined as HHCWs. Standardized incidence ratios (SIRs) for all cancer types and standardized mortality ratios were calculated. Results: A total of 107,646 HHCWs were followed up, and the total follow-up duration was 905,503 person-years. Compared to the total workers, female HHCWs showed significantly higher SIR for all cancers (observed cases = 1480; SIR = 1.25; 95% confidence interval [CI] = 1.06–1.47). The incidence of breast cancer among female HHCWs was significantly higher compared to that among total workers (observed cases = 376; SIR = 1.21; 95% CI = 1.09–1.36). Conclusions: Our findings indicate that female HHCWs have an elevated probability of developing cancer, which suggests that occupational risk factors such as night-shift work, anti-neoplastic medications, stressful jobs, and ionizing radiation should be assessed. Further investigation and occupational environment improvement activities are required.

Cancer risk in Vietnam war veterans from the Korean Vietnam war veterans' health study cohort

Introduction

During the Vietnam War, several unknown chemicals, such as Agent Orange, were used in Vietnam by the military. Therefore, there have been continuous health concerns among the Vietnamese population and veterans exposed to these hazardous chemicals. This study aimed to investigate the risk of all cancers and also organ-specific cancers among Korean veterans of the Vietnam War.

Methods

This study used a national representative cohort that included all Korean Vietnam War veterans as the interest group, with 1:4 age-sex-region-matched general Korean citizens as the reference group, from 2002 to 2018. Age-standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated for all cancers and for 31 organ-specific cancer categories based on the medical facility visit data.

Results

An increased SIR of 1.07 (95% CI, 1.06-1.08) was observed for all cancers among the veterans. There was a significantly increased risk of cancer among 22/31 organspecific cancers, with 18 cancer categories showing a significantly higher risk than all cancers. The highest risk was observed for "malignant neoplasms of other parts of the central nervous system" (SIR, 1.71; 95% CI, 1.51-1.92).

Discussion

This study evaluated the risk of cancer among Korean Vietnam War veterans. Further studies are warranted to investigate various health determinants in the veterans as well as the Vietnamese population.

Cancer risks from cosmic radiation exposure in flight: A review

Aircrew (consisting of flight attendants, pilots, or flight engineers/navigators) are exposed to cosmic ionizing radiation (CIR) at flight altitude, which originates from solar activity and galactic sources. These exposures accumulate over time and are considerably higher for aircrew compared to the general population, and even higher compared to U.S. radiation workers. Many epidemiological studies on aircrew have observed higher rates of specific cancers compared to the general population. Despite high levels of CIR exposure and elevated rates of cancer in aircrew, a causal link between CIR and cancer has yet to be established. Many challenges still exist in effectively studying this relationship, not the least of which is evaluating CIR exposure separately from the constellation of factors that occur as part of the flight environment. This review concentrates on cancer incidence and mortality observed among aircrew in epidemiologic studies in relation to CIR exposure and limitation trends observed across the literature. The aim of this review is to provide an updated comprehensive summary of the literature that will support future research by identifying epidemiological challenges and highlighting existing increased cancer concerns in an occupation where CIR exposure is anticipated to increase in the future.

Risk and Status of Gastrointestinal Cancer According to the International Standard Industrial Classification in Korean Workers

Simple Summary

The risk of developing cancers varies depending on occupation, which is a well-known fact. It is crucial to investigate the risk of developing gastrointestinal (GI) cancer in the entire industry. In this study, we calculated the standardized incidence ratios (SIRs) of GI cancer by all industrial sectors as classified in the Korean Standard Industrial Classification (KSIC). There were noticeable differences among industries in the risk of GI cancer. The SIR of all GI cancer was highest among miners and quarriers, and second highest among transportation workers. These results suggest that further research is required to identify the risk factors present in each industry that contribute to the development of GI cancers. We believe this study can help to create tailored cancer prevention strategies for different industrial sectors.

Abstract

To compare the risk of developing gastrointestinal (GI) cancer according to industrial groups, we performed a retrospective cohort study using the database of the Korea National Health Insurance Service (NHIS). We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (95% CIs) for the types of GI cancers according to the Korean Standard Industrial Classification (KSIC) compared with the whole employee population. The highest SIR for all GI cancer was found in the “Mining and quarrying” section (SIR, 1.30; 95% CI, 1.14–1.47), followed by the “Transportation and storage” section (SIR, 1.27; 95% CI, 1.24–1.30). Miners and quarriers had the highest risk of developing gastric cancer (SIR, 1.29; 95% CI, 1.06–1.55) and cancer of the liver and intrahepatic bile ducts (SIR, 1.48; 95% CI, 1.17–1.86). Transportation workers had the highest SIR of cancer of the lip, oral cavity, and pharynx (SIR, 1.27; 95% CI, 1.13–1.43) and cancers of the rectum, anus, and anal canal (SIR, 1.27; 95% CI, 1.19–1.35). There were distinct GI cancers with an elevated risk in each industry group. Our findings imply that distinct cancer prevention programs should be developed for each industrial sector.

Premenstrual syndrome incidence rate and risk factors among the working population in the Republic of Korea: a prospective cohort study

Background

Premenstrual syndrome (PMS) is the most common disease of the genitourinary tract in women. Although a sizeable proportion of women have symptoms or diagnosed PMS, its etiology remains unclear. The purpose of this cohort is to offer incidence and relevant risk factors of PMS among reproductive-aged Korean female workers.

Methods

Cohort data used were from the National Health Insurance Service–Female Employees (from 2007 to 2015) conducted by the NHIS. A total of 121,024 female workers were analyzed to estimate the incidence and hazard ratio of PMS. PMS data was based on information obtained from medical facility visits during an eight-year follow-up.

Results

The incidence of PMS was 7.0% during follow-up periods. In industrial classification, human health and social work activities have the highest incidence (9.0%) of PMS. Cumulative incidence of PMS has continuously increased by approximately 1% annually for eight years. Adjusted hazard ratio with 95% confidence interval was significantly higher in the 15–19 years old age group (2.81, 95%CI 2.35–3.36), manual worker (1.06, 95%CI 1.01–1.12), with anemia (1.13, 95%CI 1.06–1.20), and underweight (1.21, 95%CI 1.10–1.25) compared to those in the reference group.

Conclusion

This study describes the PMS status with trend and risk factors using follow-up design among women under a middle-aged working population. Further study is warranted for better understanding on the risk factors of PMS for reproductive-aged female workers.

Modelling and Experimental Validation of a Hybrid Electric Propulsion System for Light Aircraft and Unmanned Aerial Vehicles

This article presents a numerical model of an aeronautical hybrid electric propulsion system (HEPS) based on an energy method. This model is designed for HEPS with a total power of 100 kW in a parallel configuration intended for ultralight aircraft and unmanned aerial vehicles (UAV). The model involves the interaction between the internal combustion engine (ICE), the electric motor (EM), the lithium battery and the aircraft propeller. This paper also describes an experimental setup that can reproduce some flight phases, or entire missions, for the reference aircraft class. The experimental data, obtained by reproducing two different take-offs, were used for model validation. The model can also simulate anomalous operating conditions. Therefore, the tests chosen for the model validation are characterized by the EM flux weakening (“de-fluxing”). This model is particularly suitable for preliminary stages of design when it is necessary to characterize the hybrid system architecture. Moreover, this model helps with the choice of the main components (e.g., ICE, EM, and transmission gear ratio). The results of the investigation conducted for different battery voltages and EM transmission ratios are shown for the same mission. Despite the highly simplified model, the average margin of error between the experimental and simulated results was generally under 5%.

The Impact of Hearing Loss on Clinical Dementia and Preclinical Cognitive Impairment in Later Life

BACKGROUND

Dementia and cognitive impairment were significantly associated with hearing loss. The impact of hearing loss on dementia and cognitive impairment is understudied, particularly for different effect on cognitive impairment according to types of hearing loss.

OBJECTIVE

The present study was conducted to elucidate the association between clinically diagnosed dementia and hearing loss with consideration of the type of hearing loss among an elderly population, and to explore the effects of different types of hearing loss on preclinical cognitive impairment.

METHODS

Data (n = 59,675) from the Korean National Health Insurance Service-Health Screening were used to calculate odds ratios (OR) for cognitive impairment according to type of hearing loss (conductive, sensorineural, mixed, and noise-induced hearing losses, and presbycusis). Cognitive impairment was assessed using the Korean Dementia Screening Questionnaire-Prescreening (KDSQ-P).

RESULTS

Cognitive impairment was significantly associated with conductive (OR: 1.45, 95% confidence interval (CI): 1.20-1.77), sensorineural (OR: 1.23, CI: 1.12-1.36), and noise-induced hearing loss (OR: 1.32, CI: 1.12-1.56), and presbycusis (OR: 1.53, CI: 1.25-1.87). Among participants scoring positive on the KDSQ-P (score≥4), the KDSQ-P score was significantly elevated in the mixed and noise-induced hearing loss groups.

CONCLUSION

This study revealed a significant correlation between different types of hearing loss and cognitive impairment. Noise-induced hearing loss is especially important because it occurs earlier than other types of hearing loss and has large effects on cognitive impairment.

Research on Energy Management of Hybrid Unmanned Aerial Vehicles to Improve Energy-Saving and Emission Reduction Performance

The rapid development of industry results in large energy consumption and a negative impact on the environment. Pollution of the environment caused by conventional energy sources such as petrol leads to increased demand for propulsion systems with higher efficiency and capable of energy-saving and emission reduction. The usage of hybrid technology is expected to improve energy conversion efficiency, reduce energy consumption and environmental pollution. In this paper, the simulation platform for the hybrid unmanned aerial vehicle (UAV) has been built by establishing the subsystem models of the UAV power system. Under the two chosen working conditions, the conventional cruise flight mission and the terrain tracking mission, the power tracking control and Q-Learning method have been used to design the energy management controller for the hybrid UAV. The fuel consumption and pollutant emissions under each working condition were calculated. The results show that the hybrid system can improve the efficiency of the UAV system, reduce the fuel consumption of the UAV, and so reduce the emissions of CO₂, NO_x, and other pollutants. This contributes to improving of environmental quality, energy-saving, and emission reduction, thereby contributing to the sustainable development of aviation.