Prediction Equations for FVC and FEV1 among Korean Children Aged 12 Years / 예방의학회지

OBJECTIVES: Changes in lung function are frequently used as biological markers to assess the health effects of criteria air pollutants. We tried to formulate the prediction models of pulmonary functions based on height, weight, age and gender, especially for children aged 12 years who are commonly selected for the study of health effects of the air pollution. METHODS: The target pulmonary function parameters were forced vital capacity(FVC) and forced expiratory volume in one second(FEV1). Two hundreds and fifity-eight male and 301 female 12-year old children were included in the analysis after excluding unsatisfactory tests to the criteria recommended by American Thoracic Sosiety and excluding more or less than 20% predicted value by previous prediction equations. The weight prediction equation using height as a independent variable was calculated, and then the difference of observed weight and predicted weight (i.e. residual) was used as the independent variable of pulmonary function prediction equations with height. RESULTS: The prediction equations of FVC and FEV1 for male are FVC(ml) = 50.84 x height(cm) + 7.06 x weight residual - 4838.86, FEV1(ml) = 43.57 x height(cm) + 3.16 x weight residual - 4156.66, respectively. The prediction equations of FVC and FEV1 for female are FVC(ml) = 42.57 x height(cm) + 12.50 x weight residual - 3862.39, FEV1(ml) = 36.29 x height(cm) + 7.74 x weight residual - 3200.94, respectively.

Evaluation of Health Exams on Local Vibration Illness among Shipyard Workers / 대한산업의학회지

A hand-arm vibration syndrome, local vibration illness, occurs in some workers who use hand held vibration tools. It consists of white fingers, diffusely distributed finger neuropathy, pain in the hand and arm, and a small excess risk of osteoarthritis. This study is aimed to identify effective methods to confirm local vibration illness among various health exams, which are mentioned in worker's special health exam regulation. In addition, this study is aimed to quantitatively assess the daily vibration exposure level as a major determinant of vibration illness. The subjects, 46 vibration workers, were selected according to the results of the first special health exam about vibration hazards at shipbuilding industry in 1997. They all had experiences of work related blanching of fingers. Fifteen controls, who had no vibration exposure at all, were also recruited to compare their test results with the results of vibration workers. We adopted 1 subjective and 6 objective tests to evaluate the effectiveness and feasibility for confirming local vibration illness. These tests were history taking of subjective symptoms according to the Stockholm classification, checking blood pressure of finger, checking grasp power, checking finger skin temperature, nail-bed pressing test, vibration perceptional threshold test, and skin prick test for pain perception. Among these, checking skin temperature, nail-bed pressing test, and vibration perception test included cold water provocations. We also estimated some vibration exposure levels of hand held vibration tools by using previously published data from one automobile company. In conclusion, history taking of subjective symptoms according to the Stockholm classification, nail-bed pressing test, and vibration perceptional threshold test were discovered to be effective to diagnose local vibration illness. Furthermore, vibration perceptional threshold on right fingers showed a dose-response relationship to daily vibration exposure levels. The parameter beta was 0.0005(+/-0.0002), and statistically significant by REM (random effects model).

Study on Perceived Occupational Psychosocial Stress and Work-related Musculoskeletal Disorders among VDT Works / 대한산업의학회지

It has been hypothesized that jobs that have both high psychological demands and low decision latitude ('job strain") can lead to musculoskeletal disorder. The objective of this study was to test whether job strain was correlated with the presence of work-related musculoskeletal disorder, especially myofascial pain syndrome (MPS). Information on demographic factors, confounders such as household load and taking care of children or not, and scores for decision latitude, job demand, and social support was obtained by self-administered questionnaire, which had been developed in Korean language, by adopting NIOSH instrument and Extended Karasek Model (16 items). All subjects were also examined by rehabilitation medicine specialists for musculoskeletal disorders. Subjects (n=370) could be categorized into 4 groups, these were, housewives(n=89), shipyard CAD workers(n=89), general female workers(n=79; nurses, insurance counselors, public officials, clerks, etc), and telephone directory assistance operators(n=113). Results from univariate analyses indicated that all demographic factors, all confounders, scores for decision latitude and social support were not associated with the risk of musculoskeletal disorder. However, score for job demand was higher in musculoskeletal disorder cases than others. In subgroup analysis, this association was convinced again, in telephone directory assistance operators. Job strain model showed that the group of telephone directory assistance operators was high-strain group, and OR of musculoskeletal disorder was 2.446 (95% C.I. : 1.174, 5.096), when comparing this with the low strain group. In conclusion, job strain is a risk factor for work-related musculoskeletal disorder.

Current Status of Multicenter Cancer Cohort Study with Biological Materials Bank in Korea / 한국역학회지

This cohort study is a collaborative effort of 8 institutions. The goal is to establish a large scale cohort that can be followed for 10 or more years to assess the relationship between life-styles and cancer occurrence, and to evaluate the role of environmental exposures in the development of six major sites of cancers(stomach, liver, lung, colorectum, uterine cervix and female breast) in the rural population. Since 1993, 11,304 men and women aged over 35 living in four areas have been recruited. The number of target population is 30,000 persons, which is expected to be successfully recruited until 1999. Each subject has completed a detailed questionnaire on general life-styles, reproductive factors, and agricultural chemical exposures through the interview. Anthropometric measurements with body fat composition and the routine clinical laboratories were examined. For the cancer-free cohort, physical examination by the physicians and serologic tests for hepatitis markers, some tumor markers, and lipid profile have been done, but not all. In order to provide an opportunity to incorporate barious biomarkers of exposure and effect as well as genetic susceptibility, a biologic tissue bank has been established from blood and urine sample(plasma, WBC buffy-coat, RBC clots, and urine supernatant) stored at-70degrees C. Re-examination of changes in exposere to risk factors will be done periodically. Disease occurrence will be ascertained by the active(mainly through diagnosis by physicians) and the passive surveillance(through both death certificate and screening of medical utilization records).

Reliability and Validity of the Korean Version of ISAAC Questionnaire / 예방의학회지

Recent increases of asthma and allergies in childhood made the need for a standardized approach to international and regional comparisons of their prevalence and severity. To address these issues, "International Study of Asthma and Allergies in Childhood (ISAAC)" is currently underway. In Korea, "Nationwide Study of Asthma and Allergies in Korean Children" began in 1995 according to ISAAC protocol. ISAAC written and video questionnaires were used in this survey, but their reliability and validity were not evaluated properly yet. In this study, our aim was to evaluate the reliability and validity of two kinds of questionnaires and their usefulness in international and regional comparisons. The test and retest of two questionnaires were completed by male(n=110) and female(n=111) middle school students with two and three weeks interval each. Kappa(or weighted kappa) were calculated from each questions and validity coefficients were estimated from those statistics. In Korean version of written questionnaire, the questions for allergic rhinitis, atopic dermatitis, allergic conjunctivitis, and food allergy proved to have high kappa values(or weighted kappa values) and validity coefficients and they can be used in further studies without any correction. But some questions about asthma(especially nocturnal cough, wheezing in exercise, and severe asthma) and drug allergy need to be revised for better understanding to study subjects. Video questionnaire has the same degree of reliability and validity when compared to written questionnaire and this is the unexpected result. Accordingly, it also need to be revised to overcome the racial and cultural differences of the study subjects. In conclusion, the Korean version of written and video questionnaires may be considered to be useful methods in international and regional comparisons of asthma and allergic diseases in childhood after correction of some questions.

Development of Questionnaire for Evaluating Health Effect Associated with Air Pollution / 예방의학회지

This study was conducted to develope and evaluate the reliability and the validity of a questionnaire in order to determine the applicability as a screening tool for estimating environmental exposure and health effects related to air pollution. The questionnaire was developed with adopting some items of others such as ISAAC or ATS-DLD. And then we performed test-retest to 89 middle school students and their mothers at interval of three months. Cohen's Kappa values, weighted Kappa values, Spearman's correlation coefficients, and Pearson's correlation coefficients for each item were computed as reliability coefficients. The validity coefficients and validity coefficient bounds were also obtained by simply using these reliability coefficients. As results, Kappa ranged broadly from 0.10 to 0.61 of the items 'diet', 0.52~0.79 of the environmental tobacco smoke, 0.39~0.44 of the functional categories of surrounding environment, and 0.54~0.63 of the using transportation systems; these items were regarded as confounding factors. For items related to health outcomes, Kappa ranged from -0.02 to 0.37 in the respiratory system of past medical history, and from 0.11 to 0.55 in the current health status. But Kappa of the others were over 0.60. In conclusion, if some items can be corrected or modified, the questionnaire developed in this study can be used as a tool for evaluating environmental exposure and health effects associated with air pollution.

The effects of aircraft noise on the hearing loss, blood pressure and response to psychological stress / 예방의학회지

In effort to determine whether aircraft noise can have health effects such as hearing loss, hypertension and psychological stress, a total of 111 male professors and administrative officers working a college near a military airport in Korea(exposed group) and a total of 168 males and 112 females matched by age groups(control groups) were analyzed. Personal noise exposure and indoor and outdoor sound level of jet aircraft noise were measured at the exposed area. And pure tone, air conduction test and measurement of blood pressure were given to the exposed(males) and matched control groups(males and females). BEPSI(Brief Encounter Psychological Instrument) and psychological response to aircraft noise were examined for the exposed group. The noise dosimetry results revealed time-weighted averages(TWAs) that ranged from 61 to 68 dBA. However the levels encountered during taking off jet airplanes reached 126 dBA for two half minutes time period. The audiometric test showed that mean values of HTL(hearing threshold level) in exposed group at every frequency(500, 1,000, 2,000, 4,000, and 8,000 Hz were much lower than them of male and female control groups. And in old age groups, interaction of age and noise was observed at 8,000 Hz in both ears(p< 0.05). Conclusively, aircraft noise does not appear to induce hearing loss directly, but may decreased hearing threshold level by interaction of aging process and noise exposure. However, difference of mean values of exposed and control groups on blood pressure was not significantly. In psychological test, annoyance was the most severe psychological response to noise in exposed group, but mean value of BEPSI was not correlated with job duration in exposed group

Health Assessment for Glass Fibre Landfill at Gozan-dong, Inchon / 예방의학회지

In September 1994, residents of Gozan-dong, Incheon City, made a petition to the government about their health problems which might be caused by previous glass fibre landfill nearby "H" company. In February 1995, at regular academic meeting of occupational and environmental medicine, a research team of "D" University presented that they had found glass fibres in groundwater of the area through their survey. They were suspicious of probable association between ingestion of groundwater contaminated with glass fibres and skin tumors among residents. A joint research team was formed and carried out the survey of environment concerning groundwater and its glass fibre existence, and health assessment of residents in the area and industrial workers of "H" company during May to November, 1995. Analysis of groundwater flow system indicates that the flow lines from the glass fibre landfill pass through or terminate at the 6 houses around the landfill. This means that the groundwater of the 6 houses around the glass fibre landfill could be affected by some possible contaminants from the landfill, but the groundwater quality of the other houses was irrelevant to the landfill. The qualitative and quatitative analyses for glass fibres in 54 groundwater samples including those from the nearby 6 houses, were carried out using SEM equipped with EDS, resulting in no evidence for the presence of glass fibres in the waters. Major precipitates, formed in waters while boiling, were identified as calcium carbonates, in particulary, aragonites in needle form. The results of health assessments of 889 residents in Gozan-dong, participated in this study, showed statistically significant differences in past medical histories of skin tumor and respiratory disease between the exposed group (31 persons who inhabited in 6 houses around the landfill) and the control group, but no significant differences in past medical histories of other diseases, such as cancer mortality, current gastroscopic findings, current skin diseases and respiratory diseases, etc. Also, we could not prove any glass fibres in excised specimens of 9 skin tumors in both groups and there were no health problems possibly associated with glass fibres in employees of the "H" company. After all, we could not authenticate the association, raised by prior investigators, between groundwater streams, assumedly contaminated with glass fibres or not, and specific disease morbidities or common disease/symptom prevalences. That is, we could not find any glass fibres in groundwater as the only exposure factor of this study hypothesis, and there were not enough certain evidences such as increasing disease prevalences, for examples, skin, respiratory and gastrointestinal diseases etc, possibly related to glass fibre exposure, in exposed group. As a matter of course, the conditions for confirming causal association, for example, strength of the association, consistency of the association, specificity of the association, temporality of the association and dose-response relationship etc, have not been satisfied. In conclusion, we were not able to certify the hypothesis that contamination of groundwater with glass fibres might cause any hazardous health effects in human who used it for drinking.

Cost-Benefit Analysis of Back School Program for Occupational Low Back pain Patients / 예방의학회지

Although occupational low back pain accounts for 20~40% of all occupational illness and injury, there are limited numbers of studies regarding the effectiveness of back school program. The objective of this study was to evaluate the economic benefit of back school program for early return to work of occupational low back pain patients in the current occupational injury compensation and management system. The cost-benefit analysis in this study was conducted to evaluate the relative magnitude of benefit to cost. The total cost was estimated by calculating the value of components in back school program according to governmental budget protocol. The back school program was consisted of three major approaches, pain center, work-hardening program and functional restoration program and each of components had various facilities and experts. The total amount of cost was estimated as 250,866,220 won per year. The most promising type of back school program were quite intensive (a 3 to 5-week stay in a specialized center), therefore, if we adopted the 5-week stay course, 10 courses could be held in a year. Following to the medical act, 20 patients per doctor could participate in a each course, ie, total 200 patients in a year. As a result, we could estimate the cost of 1,254,331 won a patient. we estimated the benefit by using data of a few local labor offices about average medical treatment beneficiary and off-duty beneficiary of 46 occupational low back pain patients in 1994. Ullman and Larsson(1977) mentioned that the group of chronic low back pain patients who participated in back school program needed less time to recover by 48.4% of beneficiary duration. And in the trying to estimate the benefit, we asked 10 rehabilitation board certificate doctors about reduction proportion of treatment cost by introducing back school program. The answered reduction proportions were in the range of 30~45%, average 39%. As a final result, we could see that the introduction of back school program in treatment of chronic occupational low back pain patients could produce the benefit to cost ratio as 3.90 and 6.28. And we could conclude that the introduction of back school program was beneficial to current occupational injury compensation and management system.

Comparison of Diagnostic Criteria of Noise Induced Hearing Loss using Special Periodic Health Examination Data in Korea / 대한산업의학회지

Although noise-induced hearing loss (NIHL) is the most prevalent occupational disease in Korea, only 10% of the diagnosed cases are compensated. Old (1989-94) and current diagnostic criteria, criteria for workers' compensation of NIHL in Korea, compensation formulas of American Medical Association/American association of Ophthalmology and Otolaryngology (AMA/AAOO), the Committee on Hearing, Bio-Acoustics, Biomechanics (CHABA), American Academy of Otolaryngology (AAO) recommendation were compared. Each criterion was applied on the audiomety data of 4044 workers (8023 ears), who had received the second line screening test of Special Periodic Health Examination Program for noise-exposed workers during 1991-2. First, the resulting proportions of NIHL cases by employing each criterion were compared and strength of agreement was measured using kappa value. Temporary Threshold Shift (TTS) was corrected by noise free interval, and the reduction ratio of NIHL cases was calculated. Theoretical progression model of NIHL was reconstructed from previous studies on the natural course of NIHL to evaluate the change of diagnosis result of each criterion in the model. The kappa value between old and current criteria was 0.19, 0.55 for current criteria and workers' corn. criteria, ranging from 0.08 to 0.78, highest coincidence was observed between current criteria and CHABA formula. The current criteria produce most similar results with CHABA formula. If TTS is corrected for NFI, there is about 14 % reduction of NIHL cases. The results of applying on NIHL progression model divided the formulas roughly into 3 groups, of which compensation criteria was the most, old criteria and AAO the least conservative. In conclusion. The result of 4 KHZ audiometry should be excluded in evaluation of hearing level and a new hearing conservation program should be set out. Current diagnostic criteria has an ambiguity in that managerial concept for prevention arid! purpose of compensation is mixed up. The current diagnostic criteria and compensation criteria could be incorporated'into 'a new formula which is based on the state of the art test for estimating everyday hearing disability.

Perceived Occupational Psychosocial Stress and Work-related Musculoskeletal Disorders Among Workers Using Video Display Terminals / 대한산업의학회지

A cross-sectional study was conducted to assess the association between perceived occu-pational psychosocial stress at work and the work-related musculoskeletal disorders (WRMSD) among employees using video display terminals. The study included 111 female telecommunication employees from three companies at ChungBuk province. Cases of WRMSD were defined using symptom questionnaire and physical examination conducted by rehabilitation specialist. Information on demographics, individual factors, and perceived psychosocial stress, were obtained by self-administered questionnaire. For assessing perceived psychosocial stress, we used variables from 'job strain model' proposed by Karasek. Associations between perceived psychosocial stress and WRMSD were assessed by multiple logistic regression models. Forty nine (44% to the total) subjects met our operational definition for WRMSD. Age, seniority, housing load were not associated with WRMSD. Perceived psychosocial stress was associated with WRMSD [odds ratio=3.28, 95% confidence interval: 1.05-10.19]. This study suggests that perceived occupational psychosocial stress is related to the prevalence of WRMSD.

Nationwide Incidence Estimation of Uterine Cervix Cancer among Korean Women / 예방의학회지

To estimate the incidence of uterine cervix cancer among Korean women, we have conducted a study using the claim data on the beneficiaries of Korea Medical Insurance Corporation(KMIC). All medical records of the potential cases with diagnosis of ICD-9 180, 181, 182, 199, 219, 233 in the claims sent by medical care institutions in the whole country to the KMIC from January 1988 to December 1989, were abstracted and Gynecology specialist reviewed the records to identify the new cases of uterine cervix cancer among the potential cases during the corresponding period. Using these data, the incidence of uterine cervix cancer among Korean women was estimated as of July 1, 1988 to June 30, 1989. The crude rate was estimated to be 17.34(95% CI: 16.76~17.92) per 100,000 and the cumulative rates for the ages 0~64 and 0~74 were 1.7% and 2.2%, respectively. The age-adjusted rate for the world population was 19.93 per 100,000 which was higher than those of other Asian countries including China and Japan in 1983~1987. The truncated rate for ages 35~64 was 52.05 per 100,000 which was one of the highest in the world. With increasing age, the incidence rate increased to 78.11 per 100,000 in women aged 55~59 years, then it decreased in the older groups. This finding suggests that detecting rate of uterine cervix cancer may decrease in women aged 60 years or older due to detecting rate of uterine cervix cancer may decrease in women aged 60 years or older due to inadequate medical care seeking behavior. In the geographical area, the SIR of Jeju province was significantly low but it might be due to statistical unstability by small case numbers.