Job instability of Labor Market and Preplacement Health Examination: the Case of Hearing Loss / 대한산업의학회지

OBJECTIVES: This study examines the problem of the preplacement health examination in terms of hearing loss case, where workers have been experiencing job instability in the labor market. METHODS: In order to measure the 2-year job retention rate of employees in 79 shipbuilding subcontracted companies in Kyongnam province, we utilized the same methods as those used by Neumark et al(1999), and Bernhardt et al(1999). We surveyed 79 heath and safety personnel from the companies with a questionnaire to evaluate the present status of the preplacement health examination. We reviewed the preplacement health certificates(result of audiometric hearing thresholds) of 1,818 recruits issued by Daewoo hospital from January 1 to June 30, 2001. RESULTS: The job retention rate was 40.3 %(male 38.53 %, female 52.01 %). Of the 79 health and safety personnel of companies, 44(55.7 %) perceived the preplacement health examination as a tool for the selection of recruits, 3(3.8 %) as a procedure for job fitting and 31(39.2 %) as both. Most of them were against the acceptance of recruits with hearing loss, spinal disease and hepatitis. Among the 1,818 workers who underwent the preplacement health examination, 530(29.1 %) were examined after employment, but 1,096(60.3 %) were examined before employment. The number with previous job experience was 1,591(87.5 %). In the audiometric hearing threshold results, the prevalence of hearing loss was positively correlated with age. There was a significant difference in the prevalence of hearing loss depending on previous job and number of quitting at 4,000 Hz. CONCLUSIONS: The comparison of 2-year job retention rates before and after the Korean economic crisis of 1997 suggests that job stability has been aggravated especially for cohorts of long tenure, irregular job, and old age. This evidence shows that previous job and age play a role in determining worker employment based on perceived results from the preplacement health examination. This result suggests that a pre-employment health examination be substituted for the preplacement health examination based on the essential job functions and reasonable accommodation. Because it has little relevance in a wide range of employment and minor health problems, the results of this examination should not debar applicants from employment.

The Effects of Job Stress on the Autonomic Nerve Activity of Workers in Manufacturing Industry / 대한산업의학회지

OBJECTIVE: A cross-sectional study was conducted to evaluate the relationships between autonomic nerve activity (i.e., heart rate variability and urinary catecholamines) and job stress. METHODS: The study was conducted on 134 workers from a company producing consumer goods (i.e., diaper, paper towel) located in Cheonan, Korea. Job stress was assessed by Karasek's Job Content Questionnaire (JCQ). Autonomic function was assessed by heart rate variability (HRV) and urinary catecholamines (epinephrine, norepinephrine, and dopamine). Urine samplings, and measurings of HRV, were repeated three times for each shift. Information on demographic characteristics, previous job histories, past medical history, smoking and drinking were also collected. RESULTS: No statistically significant differences were observed in any HRV and urinary catecholamines among the four groups, which were categorized by the Job Strain Model. When data were stratified by work duration, low field HRV was borderline significantly higher in the high strain group in individuals with a shorter work duration (<48.5 months, N=28, p-value of 0.92 by analysis of variance). CONCLUSIONS: Neither HRV nor urinary catecholamines are significantly associated with job stress, as assessed by the Karasek's JCQ. However, HRV seems to be a potential physiological indicator of job stress only in the workers with a shorter work duration.

Risk factors influencing to mortality and recurrence after first cerebral infarction

BACKGROUND: Cerebral infarction is one of the common cause of death in Korea. There are many studies about risk factors of cerebral infarction in the world and Korea, and there are some studies about risk factors of mortality and recurrence after first cerebral infarction in the world, but there are no reliable epidemiologic studies about risk factors of mortality and recurrence after first cerebral infarction in Korea. So this study was designed to investigate the risk factors of mortality and recurrence after first cerebral infarction in Korea. METHODS: A cohort of 257 patients with diagnosing first cerebral infarction at our hospital were selected and followed for at least 5 years. 30 days, 1 year, 5 year cumulative mortality and recurrence was calculated. Risk factors classified at the time of first cerebral infarction, and then entered into a Cox proportional harzards model for mortality and for recurrence. RESULTS: The cumulative risk of mortality after first cerebral infarction was 13% at 30days, 21% at 1year, 49% at 5years. The cumulative risk of recurrence after first cerebral infarction was 4% at 30days, 11% at 1year, 24% at 5years. The significant risk factors of mortality after first cerebral infarction were age(> OR =65), heavy alcohol drinking history, heart failure, untreated diabetes mellitus history, untreated hypertension history, high admission Hct(> OR =50%), high admission glucose(> OR =200), atrial fibrillation at admission, under drowsy mental state at admission, embolic infarction type, high admission systolic blood pressure(> OR =160), high admission diastolic blood pressure(> OR =100). The significant risk factors of recurrence were age( OR =200). CONCLUSION: Diabetes mellitus, hypertension, heavy alcohol drinking, cardiovascular disease were important factor of cerebral infarction prognosis on our study. So primary care physicians focus on these factors when treating cerebral infarction patient.

The Association of Workplace Cumulative Noise Exposure and Blood Pressure / 대한산업의학회지

OBJECTIVES: The association of workplace cumulative noise exposure and blood pressure was investigated in this study using cross-sectional design. METHODS: The study population comprised 852 manufacturing male workers of whom occupational health examination data, questionnaire and personnel records were available. Workplace ambient noise monitoring data was used for calculating individual cumulative noise exposure level. Mean of each systolic and diastolic blood pressure of occupational health examination data was used for individual systolic and diastolic blood pressure level. Possible confounding variables including family history of hypertension, smoking habit, alcohol drinking habit were collected by questionnaire. On the basis of job location and duration of work at the location, a cumulative time-weighted average noise level was calculated for each workers. According to this cumulative noise exposure level, each study subject was categorized as low noise exposure group, moderate noise exposure group, high noise exposure group, very high noise exposure group. Among noise exposure groups, mean of systolic and diastolic blood pressure was compared after adjusting possible confounding variables such as age, body mass index, serum cholesterol level, family history of hypertension, smoking history, alcohol drinking habit. RESULTS: After adjusting possible confounding variables, noise exposure group was significant explanatory variables for both systolic and diastolic blood pressure, and mean of both systolic and diastolic blood pressure of very high exposure group was higher than that of low exposure group. CONCLUSIONS: These findings suggested that the high cumulative noise exposure might elevate the blood pressure.

Influence of Shiftwork Duration on Blood Pressure and Heart Rate Variability in Short Rotating 8-hour Shiftworkers / 대한산업의학회지

OBJECTIVES: This study was performed to investigate the chronic health effect of shiftwork on cardiovascular system. METHODS: We checked blood pressure(BP) and heart rate variability(HRV) at every shift on 134 male workers whose shift type was 8-hour and short rotating of 3 days shift interval. As confoundings, job stress was measured by Karasek's JCQ 49 items questionnaire and circardian type was assessed by morningness-eveningness questionnaire. Smoking and alcohol drinking habit, marital status and past medical history were also acquired. We used the method of repeated measured data analysis with mixed model to show the association between shiftwork duration and BP or HRV. RESULTS: Average age of workers was 29 years olds(range 25~44). Among them, 77.9 % were current smokers, 50 % were the passive type of job strain in Karasek's model. Mean shiftwork duration was 5.21 years(range 5.4 months~10 years). In circadian type, no one was definitely morning type or definitely evening type. In multivariate analyses adjusted by age, job strain, shift, circadian rhythm and smoking, blood pressure were showed significantly increasing trends according to shiftwork duration in both systolic and diastolic(p<0.05). Heart rate variability were also showed significantly decreasing trends according to shiftwork duration in both parasympathetic and sympathetic functions(p<0.05). CONCLUSIONS: The results of this studs suggests the chronic negative health effect of shiftwork on cardiovascular system.

The relationship between alcohol consumption and serum liver enzymes in men

BACKGROUND: It is well known that heavy alcohol consumption may result in various lesions on multiple organs and tissue, especially liver. The aim of this study was to measure prevalence of raised liver derived enzymes in healthy men and possible association with alcohol consumption, smoking and body mass index. METHODS: All subjects were 450 men who received Adult Health Examination at Seoul Hospital of Konkuk medical center from May, 1998 to October, 1998. We carried out telephone survey and analyzed 360 men, excluding men with HBs Ag(+), hepatic problems within 6 months, medication drug that could change serum activity of hepatic enzyme or joints, myscles, cardiac problem and non responder to telephone survey. We examined prevalence of raised liver enzymes and its possible association with alcohol consumption, smoking, and body mass index, applying logistic regression analysis. RESULTS: In 20.3% of study subjects, we found raised levels of lver derived enzymes. If the alcohol consumption was higher than 270 g/week, the odds ratio(OR) for raised liver enzymes, adjusted for body mass index and smoking, increased ; serum gamma glutamyltransferase(gamma GTP)(OR: 9.48), serum aspartate aminotransferase(AST)(OR: 13.09), and serum alanine aminotransferase(ALT)(OR: 7.40). Smoking was not associated with the risk of raised liver enzymes and obesity(body mass index 25 kg/m2) showed a positive association with two enzymes; gamma GTP(OR: 1.92) and ALT(OR: 2.08). CONCLUSION: If alcohol consumption was higher than 270 g/week, the risk of raised liver enzymes increased dramatically and gamma GTP, AST were shown more sensitive than ALT in alcoholic liver disease.

The Health Status Assessment of Subcontracted Workers / 대한산업의학회지

OBJECTIVES: The strategy for the labor flexibility through subcontracted labor have brought a negative effect on the lives of the workers, such as the increase of the unstable employment. This study was conducted to analyze the relationship between the employment of subcontracted firms and the health status of them, and to find out some problems which have been caused in the process of health evaluation and the characteristics of social exclusion. METHODS: We reviewed the periodical health examination and preemployment health examination in order to compare health status of the subcontracted workers with those of the parent firm workers. The SF-36 questionnaire was administered to assess the self-perceived health status. RESULTS: The result shows that compared to the working duration of the parent firm workers, those of the subcontracted workers were shorter, and the job transfer rate was higher. In the periodical health examination, the prevalence of occupational and general disease was higher in the parent firm(10%) than in the subcontracted firms(6%). Preemployment health examination plays an important role in worker's health management. Among 6,260 workers who received preemployment health examination, the prevalence of disease was 37.9%. Mean scores of health status measured by SF-36 were lower in the subcontracted firm than in the parent firm. CONCLUSIONS: Due to social exclusion of the subcontracted workers from the periodical health examination, there is a possibility that the periodical health examination have the healthy worker effect. These results suggests that the preemployment health examination could be a more appropriate indicator which is able to assess the health status of the subcontracted workers than the periodical health examination.

The Similar Exposure Group and Exposure Variation in Ship-Building Painters: Focused on Xylene Exposure / 대한산업의학회지

OBJECTIVES: This study was conducted to assess the concentration of xylene exposure and exposure variability of a similar exposure group(SEG) in accordance with job title and confined space. METHOD: The study subjects included 28 workers working in the painting process in the ship-building industry. Measurement of subjects were repeated three times. Within and between-worker exposure variance components were estimated from log-transformed exposure concentrations employing a one-way nested random effects analysis of variance model. A uniformly exposed group was defined as one where the between-worker variance(sigmaB2) was less than or equal to 0.031 or bwR95 or=0.031) and the ratios of the 97.5th and 2.5th percentile workers of the log normally distributed exposures of each group of workers was more than 2. However dividing job title into confined space(in-block, out-block, in/out-block) decreased the between-worker exposure variability. CONCLUSION: This study focused on the quantitative aspects of exposure in painters in the ship-building industry. We cannot accept the assumption that SEG are uniformly exposed, as a major component of variation in exposure relates to differences in tasks or other factors. Therefore, the observational schemes can be improved by investigating jobspecific task and practice.

A Meta-analysis on the Association between Chronic Noise Exposure and Blood Pressure / 예방의학회지

OBJECTIVES: This study was conducted to integrate the results of studies assessing the association between chronic noise exposure and blood pressure. METHODS: Using a MEDLINE search with noise exposure, blood pressure and hypertension as key words, we retrieved articles from the literature that were published from 1980 to December 1999. The criteria for quality evaluation were as follows: 1) the study subjects must have been workers employed at a high noise level area 2) The paper should use average and cumulative noise exposure as method for exposure evaluation. 3) Blood pressure in each article should be reported in a continuous scale Among the 77 retrieved articles, six studies were selected for quantitative meta-analysis. Before the integration of the regression coefficients for the association between blood pressure and noise level, homogeneity tests were conducted. RESULTS: All studies were a cross-sectional design and the study subjects were industrial workers. Five papers used a time-weighted average for noise exposure and only one paper calculated the cumulative noise exposure level. The measurement of blood pressure in the majority of studies were accomplished in a resting state, and used an average of two or more readings. The homogeneity of studies was rejected in a fixed effect model, so we used the results in a random effect model. The results of the quantitative meta-analysis, the weighted regression coefficient of noise associated with systolic blood pressure and diastolic blood pressure were 0.05 (95% confidence interval [CI]: -0.03, 0.13) and 0.06 (95% CI: -0.01, 0.13), respectively. CONCLUSIONS: Our results suggested that chronic exposure to industrial noise does not cause elevated blood pressure.

A Case of Multiple Splenic Infarction in Polycythemia Vera treated with Phlebotomy alone / 대한내과학회지

Polycythemia vera (PV) is a chronic myeloproliferative disease characterized by an increase in the total mass of red cells. Leukocyte and platelet counts are often elevated as well. The most common complication is thrombosis, which usually involves brain, heart, gastrointestinal tract, and kidneys, but rarely involves spleen. The cornerstone of therapy for this disease is phlebotomy and it is associated with an increased risk of thrombosis, especially for patients older than 70 years, those with a history of thrombosis, and those requiring an increased frequency of phlebotomy. Concurrent treatment with myelosuppressive agents decreases the risk of thrombotic complications.Recently we experienced a case of multiple splenic infarction in PV treated phlebotomy alone in a 42-year old woman who had complained of massive splenomegaly, left upper quadrant abdominal pain and fever. CT scan of abdomen showed multiple hypodense areas suggesting splenic infarction. She was managed with hydroxyurea and salicylate instead of phlebotomy and showed a clinical improvement with lowering the platelet count and reducing splenomegaly. PV with a assive splenomegaly is prone to thrombosis and phlebotomy in such patients may contribute to the thrombotic complications by increasing platelet counts. When it is necessary to lower the platelet count or reduce splenomegaly, hydroxyurea may be more useful than phlebotomy.

A Clinical Study on Back Pain after Lumbar Puncture on Aseptic Meningitis

PURPOSE: This study is to assess the occurence rate, severity, and duration of the back pain after lumbar puncture. METHODS: The occurence rate, severity and duration of the back pain that developed after lumbar puncture were recorded prospectively in patients with aseptic meningitis who had been admitted to the department of Pediatrics, St. Benedict Hospital in Pusan, from May 1993 to July 1993. The cases with traumatic taps, repeated taps, undelying diseases and age group below 2 year were excluded. The overall number of cases included in this study was 136. RESULTS: 1) In the 136 patients, back pain was developed in 53 cases (39.0%) after lumbar puncture and mean age of 53 cases was 5.4+/-2.8 years and male to female ratio was 1.4:1. 23 cases (16.9%) were mild, 17 cases (12.5%) were moderate and 13 cases (9.6%) were severe. 2) On each age group, the incidence of back pain was as followed : These were 21 patients (38.9%) out of 54 cases in group 1 (2-4 yrs), 22 patients (37.3%) out of 59 cases in group 2 (5-8 yrs) and 10 patients (43.5%) out of 23 cases in group 3 (9-12yrs). After lumbar puncture, there were no significant correlations between occurence rate of back pain and age groups. 3) The mean intervals between onset of back pain and lumbar puncture were 0.5 day in 8 patients, 0.5-1.0 day in 25 patients (47.2%), 1.0-1.5 days in 12 patients (22.6%), and 1.5-2.0 days in 4 patients. 4) The mean duration of the back pain was 2.4+/-1.3 days, and 1.4+/-0.8 days in mild pain group, 2.9+/-1.2 days in moderate pain group and 3.3+/-1.2 days in severe pain group. The mean duration of the back pain was significantly longer in moderate and severe pain groups than mild pain group (p<0.01). CONCLUSIONS: In the patient with aseptic meningitis, occurence rate of the back pain after lumbar puncture was 39.0%. All back pain were subsided within six days after onset of pain.