The Association Between the 10-Year Risk of the Korean Stroke Risk Prediction Model and the Carotid Intima-Media Thickness

BACKGROUND: Both carotid intima-media thickness (IMT) and global risk score of cardiovascular disease were independent risk factors of stroke and heart disease. We assessed the correlation between the 10-year risk of Korean Stroke Risk Prediction model (KSRP) and carotid intima-media thickness. Additionally, from a perspective of carotid IMT measurement following KSRP risk stratification, we analyzed the difference of carotid IMT and plaque according to the KSRP risk strata. METHODS: Subjects were 282 persons who visited one hospital for the screening of stroke. The 10-year risk was calculated automatically based on the equation of KSRP model. The maximal carotid IMT and the plaque were adopted as the study variables. The sensitivity and the positive predictive value of the KSRP risk categories were calculated. RESULTS: The correlation coefficient between the KSRP risk and the maximal carotid IMT was 0.29 (p<0.01). The mean (+/-standard deviation) of KSRP risk of the group with carotid plaque was statistically significantly higher, 5.3 (+/-4.1), than that of the group without plaque, 3.3 (+/-3.1) (p< or =0.01). The sensitivity of the risk stratum with more than 6% of KSRP risk for the plaque was 28.2%. The positive predictive value of the above cut-point was 48.8%. CONCLUSIONS: The 6% of KSRP risk may be considered as the beginning point of intermediate risk stratum to recommend the carotid ultrasonography. However, generalization needs further studies for various populations.

A Case of Exercise-induced Rhabdomyolysis with Hepatitis / 대한산업의학회지

BACKGROUND: Rhabdomyolysis is a relatively rare disease caused by various factors and is characterized by skeletal muscle damage. While crush injury is the most common cause in Korea as well as other countries, overexertion is an important common cause among young men in daily life. Although exercise-induced rhabdomyolysis is already well published among athletes or military persons, there have been few reports in workers. CASE REPORT: We observed a 28-year-old male worker who had elevated liver transaminases during a periodic workers' health checkup. Although he did not exhibit the typical pattern of toxic hepatitis, we had to exclude any possibility of dimethylacetamide-induced hepatitis (DIH) because he had worked in a spandex-producing factory, which already had a history of many DIH cases over several years. We performed careful history taking, several laboratory tests, liver ultrasonography and liver biopsy. We also investigated the results of biological monitoring and air concentrations of dimethylacetamide. The findings from these examinations supported the clinical diagnosis of exercise-induced rhabdomyolysis with hepatitis. CONCLUSION: This case demonstrates that exercise can induce rhabdomyolysis and hepatitis. This disease must be treated by prompt and appropriate management because it might develop more serious complications such as acute renal failure.

Blood Lead Levels in Umbilical Cord and Neonatal Neurobehavioral Status / 대한산업의학회지

OBJECTIVES: To investigate the relation between umbilical cord blood lead level lower than 10 microgram/dl and neonatal neurobehavioral performance. METHODS: Umbilical cord blood lead level, as an indicator for prenatal exposure to lead, and Brazelton neonatal behavioral assessment scale (NBAS), as an indicator for effect, were determined in 86 neonates in Gumi, Kyungpook, Korea. The blood levels were measured by graphite furnace atomic absorption spectrophotometer. Development was assessed by NBAS at birth in 86 neonates and at 1 month in 55 neonates. RESULTS: The mean cord blood lead levels of the 86 and 55 neonates were 3.90 +/- 0.71 microgram/dl (range 2.24 - 5.39 microgram/dl) and 3.88 +/- 0.70 microgram/dl (range 2.24~5.03 microgram/dl), respectively. We used the median value of 4 microgram/dl to divide into low- and high- lead level groups. There was a significant difference in the peak of excitement at birth, and in the animate visual, inanimate visual, inanimate auditory, activity level, peak of excitement, and liability of states at one month, between the two groups. For cluster scores, motor system and state organization scores showed significant differences between the two groups. For adjusting the potential confounding effect of intial difference, differences of the scores between the two groups at one month were analysed with ANCOVA. The results of ANCOVA showed the significant difference between the two groups. CONCLUSIONS: The findings suggest that prenatal low-level lead exposure, even lower than 10 microgram/dl, might affect the neonatal neurobehavioral development.

Surveillance of Work-related Diseases in Kumi / 대한산업의학회지

OBJECTIVES: Area-based occupational disease surveillance in Kumi (KODS) was used to collect data on occupational diseases. The data was used to estimate the magnitude of the diseases, to analyze for their characteristics, and to find links for their intervention and prevention. METHODS: Since January 2001, occupational physicians and nurses in Occupational Health Service (OHS)have reported six major occupational diseases; occupational musculoskeletal disorders of the upper extremities(MSDUE), occupational dermatoses, toxic hepatitis, occupational asthma (OA), hand-arm vibration syndrome(HAVS), and occupational cancer. For the respective diseases, a reporting sheet and operational diagnostic criteria were developed by the KODS. An analysis of the KODS data, collected over a certain period, was compared with data from the Korea Labor Workers Corporation (KLWC) and the Specific Health Examination (SHE), and the incidence rates of the diseases estimated. RESULTS: Between Jan 2001 and Apr 2002, 287 cases of the six major occupational disease were reported. Of these, there were 132 (46.0%), 100 (34.8%), 34 (11.8%), 16 (5.6%), and 5 (1.7%), cases of MSDUE, occupational dermatoses, toxic hepatitis, OA, and HAVS, respectively. But, there were no cases of occupational cancer. 33 (11.5%) of the incidence were reported via the OHS, 206 (71.7%) from health checkups, and the other 48(16.8%) from other routes. The synthetic fibers and electronic components manufacturing industries accounted for the greatest number of reported cases. With respect to occupation, the greatest numbers of incidence were reported from the elementary occupations, textile workers, assemblers, and cooks and food services worker, in that order. Of the MSDUE cases, carpal tunnel syndrome and epicondylitis were the two most common diseases. Most of the occupational dermatoses were due to contact dermatitis, with organic solvents (59%), nickel (6%), and epoxy resin (5%) accounting for the majority of these cases. All cases of toxic hepatitis were induced by dimethylformamide or dimethylacetamide, which were reported by a unique monitoring system. During same period, there were no cases claimed by workers to the KLWC, and only three cases from SHE, were identified. Using data from workers' number and surveillance, the annual incidences of MSDUE, dermatoses, hepatitis, OA, and HAVS, per 100,000 workers were 63.6, 48.2, 17.9, 7.7, and 2.4, respectively. CONCLUSIONS: These results show that an area-based surveillance system can be very effective for the collection of data on work-related diseases, at least in Kumi.

Three Cases of Skin Pigmentation Caused by 2,5-Hexanedione / 대한산업의학회지

OBJECTIVES: To report on the skin discoloration experienced by three workers handling 2 , 5 -hexanedione METHODS: Three workers, who showed orange-brown discoloration of the palms during observation under the Kumi occupational disease surveillance system, had their history evaluated and underwent physical examination. A workplace survey was performed by an occupational physician and an industrial hygienist. RESULTS: The three workers were determined to have been experiencing skin discoloration since the introduction of a new cleaning solvent. The new solvent contained 2,5-hexanedione, which is reported in the literature to be possibly capable of causing orangebrown discoloration of the skin. After discontinuation of solvent use, the workers recovered within a week. CONCLUSIONS: These cases demonstrate that 2,5-hexanedione can produce skin pigmentation.

Hand-Arm Vibration Syndrome and Neural Conduction Impairment in Swagging Workers Exposed to Hand-Arm Vibration / 대한산업의학회지

OBJECTIVES: To investigate the hand-arm vibration syndrome (HAVS) among symptomatic swagging workers exposed to hand-arm vibration, using medical evaluation and measurement of workplace vibration. Furthermore, to evaluate the neurophysiological METHODS: Four workers showing symptoms relevant to HAVS were evaluated. Medical evaluation consisted of medical interview, questionnaire, nail-bed compression test, and sensory perception tests for vibration and pain. Some other diseases were excluded by a medical interview, hematological assessment, and urinalysis. Cold provocation test was used to assess the peripheral vascular changes, and a nerve conduction velocity (NCV) test was implemented to ascertain the peripheral neural changes. Pegboard, hole plate, and tapping board tests were performed to assess motor nerve function. The hand-arm vibration acceleration levels of the swagging machines were measured. Six months later, follow-up NCV tests were performed. RESULTS: The actual exposure time to vibration was not longer than 15 minutes per day. The hand-arm vibration acceleration levels of the swagging machines, according to actual exposure time, were from 3.63 to 12.98 m/sec2, by ISO 5349. The vibratory perception thresholds and the recovery time of a nail color following finger cooling were significantly increased in all four workers. The perception of pain was mildly increased. The nerve conduction studies at first diagnosis and follow-up showed multifocal neural impairment caused by vibration. However, we could not rule out the concomitant presence of the carpal tunnel syndrome in one worker. CONCLUSIONS: These results show that HAVS can be caused by hand-arm vibration in swagging workers. Interestingly, the NCV results suggested that vibration-induced neural conduction impairments could vary, and need to be interpreted cautiously.

Relation of psychosocial stress, eye strain, and critical flicker fusion of VDT workers

To clarify that the psychosocial factors affect the eye strain of the VDT workers, self-reporting questionnaire about eye strain, critical flicker fusion(CFF), and 12-item version of General Health Questionnaire(GHQ) were carried out to 13 female VDT workers who have done the electronic editing and 10 female controls who were nurses in one hospital. The sum of eye symptoms of VDT workers were significantly higher than controls, but CFF of both groups were not different. And the sum of eye symptoms and CFF were not correlated. High stress group(sum of GHQ > 3) shows significantly more eye symptoms than low stress group. This result suggest that the psychosocial factors could affect the eye strain of VDT workers.

A Case of Line Maintenance Work-Related Asthma

OBJECTIVES: To investigate the work-relation of the asthma of a 51-year old aircraft maintenance worker and his working environment METHODS: For 2 weeks, the patient went back into his workplace. The pulmonary function test including FEV1 was performed every other day morning in the hospital and peak expiratory flow rate(PEFR) self-monitoring was done 6 times a day. RESULTS: The patient has been worked as aircraft maintenance worker in line maintenance department since 1968. The pulmonary function test(PFT) with bronchodilator confirmed the asthma of the patient. He showed positive response to 2-weeks workplace challenge test. On 3rd day after stopping challenge exposure, FEV 1.0 was 1.04 L(55 % of baseline measurement). The result of PEFR self-monitoring showed progressively deteriorating pattern, baseline PEFR was 6.02 L/min but PEFR on 3rd day after stopping exposure was 2.43 L/min. CONCLUSIONS: The present case could be occupational asthma based on positive results of PEFR monitoring. Further research will be needed to find the specific agent to cause asthma in aircraft maintenance workers exposed to aviation fuel and jet stream exhausts.

A Case Report of Surgical Removal of Gastric Bezoar Formed by Ingestion of Bond in AIDS Patient

Despite the increasing number of patients with human immunodeficiency virus (HIV) infection, surgical experience with these patients remains limited in Korea. Patient with HIV infection may require surgery for the reasons similar to those anyone else might need an operation for or because of problems related to their viral illness. Surgeons feel threatened by the risk of contamination when operating on HIV-seropositive or AIDS patients. However, the exclusion of patients from treatment is unethical on ground of contamination risk. Therefore the surgeons have to reconsider their surgical strategy and technique in order to keep chances of contamination as low as possible. We report a case in which the AIDS patient has undergone an operation for gastric bezoar. To our Knowledge, this is the first report of laparotomy in Korea in patient with AIDS.

An annual survey of occupational injury at a Korean Air-base

The survey of occupational injury has not been performed in Korean Air Force. The aim of this survey is to identify the feature of the occupational injury at the Korean Air force base. The occupational injury were monitored at the medical group in a Korean air base, from Aug 1998 to Jul 1999. Because the medical group has supported 2 different groups, we analysed and described some results seperately; group 1 consisted of workers in line maintenance operation, group 2 included workers in base maintenance operation. There were 59 injuries(injured persons) in group 1, and 9 injuries in group 2, so the incidence(per 1000) were 21.5, 4.46 respectively. 11 persons transferred to well-equiped hospital. Most of injured persons were air men, and then sergeant, civilian employee in order. The median age of injured persons was 22 years old in group 1 and 21 years old in group 2. The median work experience was 0.8 and 8 years respectively. The median delay time to arrive at the hospital from the time of injury were 30 min in group 1, 20 min in group 2, but maximum delay in group 1 was about 9 days. The occupational injuries were most common in October in the year, Tuesday in a week. Also the injury occurred common from 13 to 13:59, and from 11 to 11:59 in a day. The injury occurred most commonly by the collision with something, when working with more than 4 coworkers, and repairing the machinery. The most common injured part of the body were hands and feet, the patterns of injury were laceration and fracture.

Noise Induced Hearing Loss of 3 military workers that satisfied guidelines of occupational disease in Korean Occupational Safety & Health Act

Noise induced hearing loss (NIHL) is the most common occupational disease in Korea. However, there have not been reported NIHL in military workers that satisfied the decision guidelines of Korean Occupational Safety & Health Act. It is well known that aircraft maintenance workers expose to intensive noise. We found 3 military aircraft maintenance workers with NIHL that satisfied the decision guidelines of occupational disease in Korean Occupational Safety & Health Act. They were all in the base maintenance department and have work durations over 20 years. We hope these cases were sentinel events that activate the military occupational health management system.

Validation of Neurobehavioral Tests for Occupational Screening (NTOS): results of patients of Parkinson's disease / 예방의학회지

Validation and Standardization of neurobehavioral instrument in Korean occupational setting has not been studied ever. This study tried to validate the newly developed computerized psychomotor tests, Neurobehavioral Tests for Occupational Screening (NTOS). Male patients with Parkinson's disease(n=12) and male workers who never exposed to occupational neurotoxic materials and didn't have neurologic disease(n=21), performed some tests from NTOS; simple reaction time, choice reaction time(2 choice), and finger tapping(both hands). In simple analysis, difference between patient group and worker group was significantly great. Adjusted for age and education years, simple reaction time and finger tapping(both hand) were statistically significantly different between two groups(p<.05). Choice reaction time was also different(p<.1) but error frequency of choice reaction time test was not. Generally, this results showed NTOS could detect impairment of psychomotor function. But insensitive results of choice reaction time was partly due to small sample size and confounding variables and so required future study and refinement at improvement of NTOS.

Neurobehavioral Effects of Low Level Lead-exposed Workers at CRT(Cathode Ray Tube) Manufacturing Factory / 대한산업의학회지

To assess neurobehavioral effects of 48 low level lead-exposed workers in CRT manufacturing factory, simple and choice reaction time test with NTOS (Neurobehavioral Tests for Occupational Screening), digit symbol and digit span with K-WAIS (Korean Wechsler Adult Intelligence Scale), and SCL-90-R (Symptom Check List 90 revised) was examined. These screening test battery reflect 3 psychological domain; psychomotor, short term memory, and symptom. Average blood lead level was 17.7 microgram/dl and mean exposure duration was 5.6 years. Nobody exceeded blood lead level over 40 microgram/dl, the guideline. We divided workers to two group, shorts-term exposed group(< or = 5 years) and long-term exposed groups 5 years) for analysis. ANCOVA model of simple reaction time, hostility, phobic anxiety, somatization were statistically significant and coefficient of independent variable of exposure duration was also significant. MANCOVA model of SCL-90-R was significant, too. The results of this study were consistent with previous study; symptoms were early neurobehavioral effects of low level lead exposure. And this study showed that current blood lead level as independent variable was able to mask the early neurobehavioral effects.

Effect of Height and Arm Length on Simple Reaction Time / 대한산업의학회지

To identify the relation between simple reaction time and height and arm length, simple reaction time was performed to medical students with measurement of height, and arm length. Participants should answer questions about Smoking, drinking, sleep deprivation, history of diseaseand drug, whether to use computer or hot Mean height of men(n=98) was 173.0+/-4.79 cm, that of women (n-22) 161.7+/-4.33 cm. Mean arm length of men was 73.5+/-3.09 cm, and that of women 68.0+/-2.93 cm respectively. Height and arm length were statistically significantly different between-men and women (plt;0.01). Mean simple reaction time of men was 265.4+/-25.03 msec, that of women 286.8+/-28.48 msec. Mean simple reaction time was also statistically significantly different(p<0.01). As a result of correlation analysis, for men. None was significant. However, for women, height and arm length showed statistically significant, correlation with mean reaction time. Correlation coefficient of height and arm length were 0.45 (p<0.05) and 10.57 (p<0.05) respectively.

Reliability and Validity of PWI (Psychosocial Wellbeing Index) / 예방의학회지

To study reliability and validity of PWl, this newly developed self-administered questionnaire which measures stress, was given to medial students. All respondent(133) were followed 4 weeks later and 92 were retested. Cronbach's a coefficient of data was 0.93. Test-retest reliability measured by pearson's correlation coefficient was 0.72(p l). After exploring 4 factor structure according to previous study results, factor 1 showed good agreement but other factors did not. Confirmatory factor analysis(CFA) showed poor fit of 4 factor model to data. In the further study, it may be considered to model that has unidimensional factor structure.

Effects of Number and Method of Visual Stimuli on Simple Reaction Time / 대한산업의학회지

In. order to evaluate the effects of number and method of visual stimuli on simple reaction time and determine the proper number of trials, simple reaction time of the computerized test of NTOS (Neurobehavioral Test for Occupational Screening) was carried out on 240 medical students. The prominent difference was found between male and female on simple reaction time. Regarding the effect of number based on the parameters of measures and the purpose of test itself, 64 trials was considered as proper number. The mean reaction time was different according to the methods of visual stimuli, such as color and size(p<0.05). The larger and more intence visual stimuli were, the faster sim-ple reaction time was. In respect to sex, that difference was similar. But, there was no difference depending upon whether the each result of each trial was showed on the monitor. The subjects, however, showed much interest when the result showed. Further studies, including the various variables on visual stimuli, are required to compare among various studies.

Development of Korean Computerized Neurobehavioral Tests arid Evaluation of Applicability / 대한산업의학회지

We tried to develop Korean computerized neurobehavioral tests to promote neurobehavioral research and screening in occupational setting in Korea. This program was designated Neurobehavioral Tests for Occupational Screening (NTOS). NTOS consisted of 3 test items, choice reaction time (2 choice and 4 choice), simple reaction time (visual and auditory stimulus), finger tapping test (both hands). NTOS was administered to 120 students of medical school and to evaluate applicability. The results of reaction time tests was positively skewed but finger tapping test was negatively skewed. The only data that was not skewed was the mean frequency of finger tapping of dominant hand. The means and standard deviations of choice reaction time were 429.7 msec and 109.8 msec (2 choice), 493. 6 msec and 92.0 msec (4 choice). The results of simple reaction time were 254 msec (mean) and 55 msec (standard deviation). The mean frequency of finger tapping of dominant hand was 77.2 and that of nondominant hand was 64.9. The results of 2 choice reaction time test and finger tapping of dominant hand showed statistically significant sex difference. Factor analysis showed 2 factors, 1st reaction tests and 2nd tapping. The mean frequency of finger tapping had negative weak correlation with other reaction time test results. This computerized neurobehavioral tests may be widely applied in the other future studies, and is to be improved for the practical purpose of the occupational neurotoxico-logical area.