Wan Cheol Lee

목적: 1997년 외환위기 이후 우리나라는 높은 비율의 비정규직 근로자 문제와 함께 높은 자살률을 보이고 있다. 이에 본 연구는 비정규직 고용상태와 자살생각 사이의 관련성을 파악하고자 하였다. 방법: 국민건강영양조사 제 1기(1998년), 제 2기(2001년), 제 3기(2005년) 및 제 4기(2007~2009년) 자료에서 20~69세의 임금근로자 13,632명을 분석대상으로 하였다. 고용형태는 정규직(상용직 전일제 근로자)과 비정규직(시간제, 임시직, 일용직 근로자)로 분류하였으며, 조사시기별로 정규직 근로자에 비교한 비정규직의 자살생각 위험도를 포아송회귀분석에 의한 유병비(prevalenceratios)를 통해 산출하였다. 결과: 제반 변수를 보정한 결과 비정규직 근로자의 자살생각 위험도는 여성에서 유병비 1.24~1.37로 모든 조사에서 통계적으로 유의하게 높았고, 남성은 유병비 1.36~1.52로 제 1기(1998년)를 제외한 모든 조사에서 유의 혹은 경계적으로 유의하게 높

Hearing loss (HL) has been related to cardiovascular risk factors as well as prevalence of cardiovascular disease itself. We evaluated the association of HL with overall, injury-related, and cardiovascular mortality. A cohort study included 580,798 Korean adults (mean age: 39.7) who attended a screening exam between 2002 and 2016 with a follow-up of up to 17 years. HL was defined as a pure-tone average of thresholds at 0.5, 1.0, and 2.0 kHz ≥25 dB (decibels) in the better ear and further categor

We examined the associations of smoking status and urinary cotinine levels, an objective measure of smoking, with the development of new-onset HL. This cohort study was performed in 293,991 Korean adults free of HL who underwent a comprehensive screening examination and were followed for up to 8.8 years. HL was defined as a pure-tone average of thresholds at 0.5, 1.0, and 2.0 kHz ≥ 25 dB in both ears. During a median follow-up of 4.9 years, 2286 participants developed new-onset bilateral HL. Sel

Abstract Objectives Long working hours are linked to an increased risk of exposure to work safety hazards that threaten the health of workers. To date, only a few cross-sectional studies regarding the relationship between working characteristics, such as over-workload and chronic kidney disease (CKD) have been reported. Therefore, in this longitudinal study, we aimed to examine the direct relationship between long working hours and the incidence of CKD. Methods We included 97 856 participants wi

OBJECTIVES: We aimed to find evidence of the inflammation-mediated mechanism by which long working hours contribute to cardiovascular disease (CVD). METHODS: This cohort study was performed in 56 953 Korean adults free of CVD who underwent a comprehensive screening examination and were followed for up to 7 years. An increase in blood high-sensitivity C-reactive protein (hsCRP) of 1 mg/L or more at the follow-up visit was defined as an incidence. The average weekly working hours in the past year

Non-alcoholic fatty liver disease (NAFLD) is a relatively common disease, and preventing its occurrence is important for both individual health and reducing social costs. Shift work is reported to have several negative effects on health. An association has been observed between NAFLD and both sleep time and quality; however, this association remains unclear in night shift workers. We aimed to evaluate the relationship between shift work and the incidence of NAFLD. Overall, 45,149 Korean workers

The use of the interior permanent magnet synchronous motor (IPMSM) has increased in the industrial field because of its excellent characteristics such as high efficiency, wide range of speed operation, and flexibility of the rotor structure. Therefore, IPMSM, especially one using the rare earth permanent magnet, is being actively studied. In IPMSM using the rare earth permanent magnet, typically the permanent magnet is deeply embedded in the rotor. The washing machine has large load variation an

Shift work has adverse health effects such as diabetes, cardiovascular disease, sleep disturbance, depression, and breast cancer. Gastro-esophageal reflux disease (GERD) results in lesions such as reflux esophagitis (RE) and Barrett's esophagus. This study investigated the association between shift work and RE. A cohort study was conducted with 140,553 participants who were followed up at least once from 2012 to 2018. Type of working and shift types were collected using standardized questionnair

This paper introduces a compact and single-packaged beam forming network for a low-cost 5G transceiver system. For low-cost, silicon IPD (integrated passive device) is used to make the 4 × 4 Butler matrix and a switch IC is embedded in the silicon to make a single package structure and wire-bonding can be removed. The conventional branch line coupler is modified to minimize its size using MIM capacitors and short transmission lines. The measured result shows RMS magnitude errors are less than 0.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD), a common chronic liver disease, may progress to fibrosis, cirrhosis, hepatocellular carcinoma, and liver failure. But only a few cross-sectional studies have reported an association of NAFLD with working hours. This cohort study further examined the association between working hours and the development of NAFLD. METHODS: We included 79,048 Korean adults without NAFLD at baseline who underwent a comprehensive health examination and categorize

Abstract Coronary artery calcium score (CACS) is a useful method for predicting coronary artery disease in asymptomatic adults. In this study, we investigated the association between prolonged sedentary time and CACS. A cohort study was conducted in 14949 men with negative CACS (CACS = 0) at baseline who were followed up at least once. Sedentary time was categorized into < 7, 7–8, and ≥ 9 h/day. CACS was calculated by cardiac tomography. During 60,112.1 person-years of follow-up, 569 particip

Long working hours have negative effects on the health of workers. Several studies have reported the association between long working hours and both diabetes and prediabetes. Therefore, we aimed to examine the temporal relationship between long working hours and glucose intolerance. Our cohort study collected data from 25,803 healthy male participants at baseline. To evaluate the risk of incident glucose intolerance, we estimated the hazard ratios (HRs) and 95% confidence intervals (CIs) using t