Epidemiologic Investigation of a Mumps Outbreak in a Middle School in Pohang, Korea: Effect of vaccination during outbreak / 한국역학회지

BACKGROUND: There was a widespread outbreak of mumps at elementary and middle schools in Pohang city in March 1999. We have carried out an epidemiologic survey to trace the source and mode of transmission of the outbreak, as well as evaluating the effect of vaccination as a measure of controlling the outbreak. METHODS: Questionnaire survey on 959 students showed that attack rate was 10.7%. There was no significant difference between genders in terms of attack rates. However, second graders outnumbered other groups as 16.9%, comparing to 8.1% among first graders and to 7.0% in the third graders. RESULTS: Cases of mumps were reported in 1998, primarily in the neighboring elementary schools. The disease was also reported earlier in 1999, sporadically. In March, however, number of the cases was sharply on the rise as the middle schools opened for a new semester. Our investigation revealed that infection stemmed from more than three different sources, particularly in the classes of second graders, and then spread to all students, corresponding to the distance between students. Effect of vaccination during the outbreak was pretty good: attack rate of the group vaccinated since May 1st, considering the maximum latent period of infections (21 days), was 0.8%, comparing to 5%. The efficiency of vaccination marked 84.8%.(95% confidence interval 79.66-89.94) Although the authors recommended the students to wear flue masks and wash their hands as often as possible to screen infections among the students, it turned out that such measures had little effect for the prevention of spread. CONCLUSIONS: The number of mumps cases dropped remarkably among vaccinated the students the prevalent period of the disease. Authors concluded that is effective to control the outbreak if it is done at early stage.

Prevalence and Risk Factors of Occupational Low Back Pain among the Production Workers in a Steel and a Welding Material Manufacturing Factories / 대한산업의학회지

A cross-sectional study was conducted for detecting the risk factors and to propose an effective control program for occupational low back pain. The subjects were 1,665 male production workers employed at a steel factory and a welding material manufacturing factory. The data were collected by a self-reported questionnaire and a medical examination with a rehabilitation specialist for ten days in September, 1997. The contents of the questionnaire were as follows: general characteristics, physical characteristics, employment status, type of work, working environment and the experience of low back pain. The number of cases with symptoms of occupational low back pain were 321, so the point prevalence was 19.3 persons/100 persons. The number of cases with a history of occupational low back pain for one year were 554, so the one year period prevalence was 33.3 persons/100 persons. The point and one year period prevalences of occupational low back pain showed no significant differences in age, marital status, educational level and body mass index. The point and one year period prevalences of occupational low back pain showed no significant differences in alcohol drinking, smoking, stretching exercise and regular exercise. The point and one year period prevalences of occupational low back pain were significantly higher in the unsatisfied group than the satisfied group(p < 0.01), However, no significant differences were found among tenures and shift work. The point and one year period prevalences of occupational low back pain were significantly higher in the lifting of heavy materials group than the nonlifting group(p < 0.01). However, no significant differences were found among posture of the waist and the working posture. Through the multivariate logistic regression, significantly associated factors with occupational low back pain were found to be dissatisfaction with job(point prevalence: OR=1.78, 95% CI: 1.21-2.61; one year prevalence: OR=1.76, 95% CI: 1.26-2.47), lifting of heavy materials(point prevalence: OR=1.94. 95% CI: 1.44-2.61: one year prevalence: OR=2.17, 95% CI: 1.70-2.77) and tenure(point prevalence: OR=1.03. 95% CI: 1.01-1.06: one year prevalence: OR=1.02, 95% CI: 1.00-1.05).

Occupational Relationship of Cancer Patients Diagnosed in Two University Hospitals / 한국역학회지

OBJECTIVES: This study was performed to evaluate the occupational relationship on 190 cases of cancer selected out of 622 cases of cancer registered in two university hospitals from January 1, 1996 to December 31, 1997. METHODS: The selection criteria was for the patient to be more than 40 years old with lung, liver, urinary bladder, nasal cavity and skin cancer or leukemia. We reviewed the medical records to update the missing data and occupational histories. Telephone interviews were used to obtain complete occupational histories on the subjects. RESULTS: The sites of cancer in the order of relative frequency was lung (51.0%), followed by liver (32.9%), urinary bladder (14.1%) and skin (2.0%) in male, liver (41.5%), followed by lung (31.7%), skin (19.5%) and urinary bladder (7.3%) in female. The occupational histories of 190 cases with suspected cancer-causing occupations were recorded 5.8% on the doctor's medical records and 33.2% on the nursing records. The response rates of the telephone interviews were 87.4%. The distribution of occupation according to the telephone interviews was farmer (47.7%), office worker (16.1%), salesman (12.8%), production worker (6.7%), simple laborer (3.4%) and unknown (13.4%) in male, housewife (63.4%), farmer (17.1%), saleswoman (9.8%) and unknown (9.8%) in female. And there were two cases of suspected occupational relationships in the lung cancer cases. CONCLUSIONS: We could not discover definite cases of occupational cancer but found out two cases of suspected occupational relationships. Occupational cancer is likely to increase in the near future, so the efforts to detect occupational relationships with cancer should be continued.

An Epidemiologic Study on an Outbreak of Dermatosis Associated with Moths at a Factory / 예방의학회지

An outbreak of dermatosis occurred at a machinery manufacture factory in kyongju on Aug 1995. Authors conducted a questionnaire survey among 92 workers in the factory and a dermatologist examined their skin lesions. Authors also collected moths and identified them. The results are as follows; 1. Forty-two cases of dermatosis were identified with attack rate of 45.7%. Attack rate was not different by company, age, sex, educational level and duration of employment. Attack rate was 47.8% among productive workers, 25.0% among clerical workers and 100.0% among patrolmen. 2. Two cases among 42 dermatosis cases and three subjects among 50 non-cases had a history of same dermatosis last year. Four of dermatosis cases had a history of dermatosis among their family members. 3. skin lesions of the cases were scattered or grouped rice-sized erythematous papules or vesicles. Duration of dermatosis from the onset to the time of survey was from one day to more than 30 days. The most frequent site of skin lesion was the arms(81.0%), and it was also observed at the neck(47.6%), abdomen(45.2%), chest(42.9%), legs(38.1%) and back(35.7%). skin lesion was aggravated with sweating(31.0%), after shower(16.7%) and with scratching(l1.9%). 4. Moths were collected and identified as Euproetis subflava(Bremer). Many poisons stings were observed on their wngs which is harmful to human. 5. Contact with moths' wing droppings to two authors on their forearms for provocation resulted in severe immediate pain followed by prolonged pruritus. Erythematous macules quickly appeared and suoceeded by firm wheal-like red papules. Authors thought that the outbreak of dermatosis was brought about by Euproetix subflava(Bremer). Further studies on the factors contributing to the prosperity of the moths in this area are needed.

Temporary Threshold Shift of Vibration Sensation by Dental Handpiece / 예방의학회지

This study was performed to investigate the possibility of temporary threshold shift (TTS) of vibration sense could induced by exposure to high-frequency vibration or by work position taking by dentists in drilling or polishing. The vibratory perception thresholds (VPT) of 28 healthy men were measured on the index fingertip pulp of dominant hand at 250Hz. The vibrating tool used in test was a low-speed handpiece of 34,000 rpm. For the TTS test, the dominant hand was exposed to high-frequency vibration and to work position for five minutes, respectively. The VPTs before and after vibratory exposure were 23.5+/-3.5 dB, 30.8+/-4.2 dB, respectively and VPT after work position was 23.7+/-4.6 dB. The difference between before and after vibartory exposure was statistically significant (P<0.001). The correlation of height, weight and BMl with baseline VPTs was not statistically significant. Also, there was no difference of VPTs by smoking. These results suggest that high-frequency vibration from dental handpieces might cause the impairment of vibration sensation.

A Survey on Physical Complaints Related with Farmers' Syndrome of Vinylhouse and Non-vinylhouse Farmers / 예방의학회지

To compare the physical complaints of vinylhouse farmers with those of non-vinylhouse farmers, a personal interviews on 250 and 142 vinylhouse farmers were conducted in Sungjoo county in Kyungpook province selected by a random sampling from July 5 to July 10, 1993. Blood pressure of the subjects was also measured. Vinylhouse farmers had a higher average age, larger family size, shorter experience of farming, more working hours per day and working days per year and higher annual income than non-vinylhouse farmers. The frequency of preticide spray of the vinylhouse farmer was 3.4times on the average in June 1993 as compared with 2.0 times of non-vinylhouse farmers, and 16.7 times for the vinylhouse farmers during the last one year while it was 8.3 times for the non-vinylhouse farmers in the same period. While 39.6% of vinylhouse farmers experienced pesticide intoxication symptoms such as headache, nausea, vomiting, dizziness, itching, and skin irritation, etc. during the month of June, 25.4% of non-vinylhouse farmers experienced such symptoms. The most frequent symptoms among eight symptoms that constitute the farmers' syndrome were lumbago, numbness of hand or foot shoulder pain and dizziness regardless of sex and type of farming. Prevalence of the farmers' syndrome in male and female among vinylhouse farmers were 22.1%, 43.4%, respectively, and the prevalence in non-vinylhouse farmers was 23.2% for male and 50.7%for female. There was no statistically significant difference in the prevalence of farmers' syndrome between vinylhouse and non-vinylhouse farmers. However, The prevalence on female was about 2 times higher than that of male When the effects of other factors were adjusted by multiple logistic regression for farmers' syndrome, the prevalence in female was 3.0 times higher than that of male. The prevalence of farmers' syndrome was increased as the age of farmers increased on both vinylhouse and non-vinylhouse farmers, and adjusted odds ratio of farmers' syndrome increased by 3% as the age increased by 1 year Adjusted odds ratio of Farmers' syndrome in farmers who experienced pesticide intoxication during the month of June was 3.7times higher than that of farmers who did not have such experience. While the prevalence of hypertension in male and female non-vinylhouse farmers were 22.4%, 13.7%, respectively, the prevalence in vinylhouse farmers were 13.5% for male and 12.0% for female. However, there was no association between farmers' syndrome and hypertension. It was found in this study that the vinylhouse farmers are at a high risk of pesticide intoxication, which is associated with the common physical complaints. To reduce such risk it is necessary to develop farming methods which do not require the pesticide of may use less pesticide, a safer method of pesticide spraying, and the protective equipments which can be worn at a high temperature and have a better protective effect. Also education of farmers for the correct methods of ventilation after pesticide spraying in the vinylhouse and wearing the protective equipments may be considered as a supportive method. Since inappropriate posture at work and intensive labor may cause farmers' syndrome, it is recommended to develop farming tools which reduce physical burden and take a rest and exercise periodically during work. It is necessary to strengthen the hypertension management program of the Kyungpook province, because the prevalence of hypertension was as high as about 15%.

Selection of Testing Frequency in Bone Vibrator of Audiometer for Measurement of Vivration Perception Threshold / 대한산업의학회지

Both to determine testing frequency in bone vibrator of audiometer for measurement of vibration perception threshold(VPT) and to evaluate factors influencing VPT, ninty seven healthy adults were tested on their second metacarpal head of both hands, at 250Hz, 500Hz, 1,000Hz and so on. Measures of the VPTs at 1,000Hz were excluded in analysis because frequency 1,000Hz was not recognized as a vibration sense. Mean and standard deviation(S.D.) of the VPTs in the both hands measured at 250Hz were 19.9+/-6.7dB, 21.0+/-7.3dB, respectively and at 500Hz were 33.6+/-8.3dB, 34.9+/-8.1dB, respectively. Both mean and S.D. tended to be lower at 250Hz than 500Hz, and mean differences of VPTs between the left and the right hand at the both frequencies appeared statistically significant (p<0.01). VPTs were significantly correlated with each other (p<0.01). Age was positively correlated(p<0.001) with VPTs and education was negatively(p<0.01). Multiple regression analysis showed that age was the only factor influenced on VPT. These results suggest that, when using the bone vibrator of audiometer for measurement of VPT, the frequency 250Hz as a testing frequency may be more useful than frequency 500Hz, and VPT should be measured on both hands.

Weighted Needle Pinprick Sensory Threshold (WPT) and Arthropornetric Parameters / 대한산업의학회지

To assess the relationship of pinprick sensory threshold with height and weight, Ninety seven healthy young (age 19 to 28) males were tested on their anatomical snuff box of both Hands. Their WPT was measured by device holding and moving weighted needle sensory threshold apparatus. Mean of the WPT was 0.43(+/-0.24) g in left and, 0.53( 0.30) g in right hand. Difference of WPT between the right and left hand appeared statistically significant (p<0.01) . Correlation coefficient of WPT with height was 0.26461 (p<0.01) in left and, 0.31856 (p<0.01) in right hand. Weight was statistically significantly correlated with WPT in left hand (r=0.24932, p<0.01) The study shows that the left-right difference and influence of height in pinprick sense may exist in normal healthy male adults.

Incidence of the Needle-Stick Injuries in Medical Students Among Clinical Training / 예방의학회지

A questionnaire survey was conducted to assess the experience of the needle stick injuries in 144 seniors of a medical school during the previous 10 months. one hundred and five of them (73%) had responded. About sixty-nine percent(72 cases) of the respondents had suffered at least one injury and there had been 129 injuries in total. Seventy-eight(56.6%) of the injuries took place at the time of the venipuncture. The emergency and operating room incurred 76.7 % and 23.3% of the injury, respectively. Injuries with bleeding account for 50.4%. None of the respondents was systematically educated about the prevention of injury. This survey shows that the needle-stick injury is a great risk for the medical students' health, and that educational effort for its prevention is warranted.

A study on pulmonary function of the navy divers / 대한산업의학회지

No abstract available.

Byssinosis in carbon textile workers in Taegu, Korea / 대한산업의학회지

No abstract available.

Formaldehyde exposure in the plywood manufacturing factory / 예방의학회지

In the plywood manufacturing factory established in 1979, female 3 workers who had exposed to adhesives containing formaldehyde for more than 48 months of duration suffered from eye, nasal, oral, throat and skin irritation and dyspnea as chief complaints. The actual level of the exposure to formaldehyde were not estimated when the exposed workers started to have above symptoms. The environmental monitoring of workplace was measured on April 25, 1990, and the concentration of formaldehyde revealed 0.2 ppm, however the exhaustive ventilatory system was already installed at that time. Twenty six subjects from entire factory were examined by questionnaire, physical examination and spirometry, etc. on August 22, 1990. Significant difference was observed in symptoms and signs of nasal, oral and throat irritation between teh exposed group with longer duration and that with short duration. When the exposed group with longer duration was compared to the group of nonexposed, symptoms and signs of nasal, oral, throat and skin irritation, chest tightness and dullness were significantly increased in the former group. The results of the spirometric test showed that the forced vital capacity and the forced expiratory volume at 1 second were decreased amont the exposed group with longer duration but not significant.

Long term noise exposure of steel mill workers, hearing loss and blood pressure / 예방의학회지

A cross-sectional study was conducted to investigate the effect of long term noise exposure on blood pressure among steel mill workers. The workers participated in periodic medical examinations performed from August 27 to September 6 in 1990. Examined were 1,034 workers with high-level noise exposure(average 91.8+/-5.2 dB{AA)), and 390 workers with low-level noise exposure(average 75.2+/-4.6 dB(A)). No significant difference was found in systolic or diastolic blood pressure between the two exposure groups. Prevalence of hypertension (> or = 160 mmHg systolic or > or = 100 mmHg diastolic) was higher in a younger age group ( or = 25dB at 1000 Hz or > or = 40 dB at 4000 Hz in at least one ear) than in the normal hearing group. From multiple regression analysis, hearing loss, body mass index, age, alcohol and family history of hypertension were proven to be predictors of diastolic blood pressure (p<0.02). When regression was performed for each age group, hearing loss was a strong predictor of diastolic pressure in the younger age group (p<0.01).

Frequency and Pattern of Traffic Accidents in Different Atmospheric Phenomena / 예방의학회지

In order to fine out the relationship between traffic accidents and atmospheric phenomena, we have analyzed 2,562 cases, one tenth of the total traffic accidents occurred in Taegu city for a year in 1988. The meteorological elements observed by Taegu Weather Bureau were used. It was divided into two largy categories: the patterns of accident as human injuries and destructions of car. When the accidents were overlapped in each other, it was considered as human injury. Human injuries were subdivided into three parts: death, severe damage. The average number of daily traffic accidents including human injuries were lowest in winter of four seasons. The accident patterns in accordance with the seasons showed statistically significant difference. The frequency was the highest as 3.3 case in an hour at 25.1-30.0 degrees C of atmospheric temperature, the rate of human injury showed the increase by the increased temperature. But there were not significant. Also it was the highest as 3.7 cases in less than 31% of humidity and the rate of human injury was the highest at 41-50%, but not significant. And it was the increasing tendency as wind speed increase, and the rate of human injury was the highest at 6.1-7.0m/sec, but it was not significant. In relation to precipitation, and visibility, were the highest as 5.4 cases at 5.1-10.0 mm of rainfall, the rate of human injury was increased by the increased precipitation and showed statistically significant. And it was highest within 6 Km of visibility, but the rate of the human injury was the lowest within same distance, and also showed significance. The accidents were higher with snow on the road, but the rate of human injury was comparatively lower, but no significance.

Relationship of Hair Copper and Mercury Contents to Personality in Chronic Schizophrenia / 예방의학회지

The relationship between copper and mercury contents in the scalp hair and chronic schizaphrenia was investigated. The samples of scalp hair were collected from 80 male chronic schizophrenic patients at the age from 20 to 20, who were hospitalized in the National Psychiatric Hospital in Seoul. As the napes and the Minnesota Multiple Personality Inventory (MMPI) was performed also. The copper and mercury contents were determined by an atomic absorption spectrophotometer. Significantly higher T-score of MMPI was seen in patients group for Hypochondriasis Scale (Hs), Depression Scale (D), Psychopathic Deviate Scale (Pd), Paranoia Scale (Pa), Psychasthenia Scale (Pt), Schizophrenia Scale (Sc) subscales than control group, and the frequency distribution by T-score was also significantly different between the patient and the control group for above scales. The content of copper in the hair of patient group was significantly higher than control group. In the case of mercury, the mean value of patient group was significantly higher than control group. Between the value of copper and mercury, statistically significant negative correlation (r=-0.25) was found. When grouped by the T-score of MMPI, there was no difference of copper contents between T-score subgroup at all MMPI scale. But the mercury contents showed significant difference between T-score subgroup at Pt, Sc scale. When compared between the group of above 70 T-score and the group of less than 70, the mercury contents of Pa, Pt, Sc scale of above 70 T-score group were significantly higher than the group of less than 70. In other scales, the mercury content of the above 70 group were higher than the group of less than 70 except Mf scale, although there were no statistically significances. In D, Pa, Sc scales, as the T-score of MMPI increased, the contents of mercury also increased. When divided into the patient group and the control group, the copper contents of the patient groups were significantly lower than the control group at each T-score scale in most MMPI scales. In the case of mercury, the value of patient group were significantly lower than the control group in the less than 44 scale of D, in the 60~69 scale of Pd, in the 45~59 scale of Mf, in the 60~69 scale of Ma, in the less than 44 of Si. These results suggest that the effects of the deficiency of copper or high intake of mercury on schizophrenia and personality may be of possible value. Thus further studies are necessary to determine whether schizophrenia and personality formation would be attributed to copper deficiency or mercury intake.

Effect of Zinc Administration on the Autistic Children / 예방의학회지

The purpose of this study was to evaluate the effect of zinc administration on the autistic children. the subject diagnosed as infantile autism were 24 male and 10 female children of a special school in Taegu city. Control group were selected from 1 : 2 ratio matched with cases on sex and age. The results were as follows. In female autistic group, the mean content of zinc in hair was significantly lower than control group, but in male the result was inverse at all age group. The content of zinc in hair showed significant correlation with age in male autistic group and control group. Zinc content of hair, age and sex accounted for 37.2% of the variance of autistic score and the most significant variable was zinc content. Autistic group were divided into two group. Group I which zinc content of hair below 150 ppm were administrated with multi-vitamin contained 10mg of zinc, Group II which zinc content of hair above 150 ppm were administrated with placebo. Total administration period was eight weeks. In zinc administration group, there was a decreasing tendency of autistic score as the zinc content of hair was increased but the relationship was not statistically significant.

A Study on Improvement of Health Care in the Small-Scale Industries / 대한산업의학회지

The purpose of tliLs study was to cvaTuate the actual condnzonK and problems of health manager health record maintenance and general health examinations in small-scale industries which employ 511 to ISO workers. A survey was conducted in 3iS conipanies in which industries health management is dele-gated to a social organization, the Taegu-kyungpook branch of the korean Industrial Health Organization, and companies in which health is managed by Ideal physicians. There was accomplished from March to April 1989 by Questionnaires through the mail, The following are the summarized results. 1. Health Management. The companies with non-vicarious execution of health management by local physicians ranked significantly, lower in frequency of visits, contribution to workers' health, and workers' desire for frequency of visits than the companies with vicarious execution by KIHA. 2. Health Records. The percentage health records on file was higher in the companies with vicarious execution than the other group. But most of the cnotents of the records were not described in great detail. 3. General Health Examination. The necessity of health examinations was recognized by all survey participants, but the reliability of the examinations was one of the major problems. The reporting period for results was significantly longer in the companies with vicarious execution than the others. Improvements were preferentially demanded with respect to the reliability of techiques and examinatio skill, follow-up study for secondary examination, and selection of examination items.

Hair Heavy Metal Contents in Mentally Retarded Children I: In Association with Lead / 예방의학회지

This paper was carried out to study on correlation between mentally retardation and lead and zinc. The subjects were 297 mentally retarded children: 132 of Bomyung special school and Sunmyung, which were located in Taegu city of Korea. The former had their parents but the latter had not. The control group 63 children were randomly seleted from the Dong-in primary school near to Medical School of Kyungpook National University. Atomic absorption spectrophotometer, model IL-551 connected with CTF atomizer(IL. 655) was used for the analysis of lead and zinc. The mean value of lead in hair of mentally retarded children was 14.97 3.71ppm which is significantly higher than that of control group, 11.36 2.83ppm. But the content of zinc was not significant in both groups. In the lead there was no significant correlation to age but significant negative correlation to IQ. Zinc showed significant correlation to age but not to IQ. Among the handicapped children, no signigicant correlation between orphan group and non orphan group. Handicaps of mentally-retarded children were speech impairment, emotional disturbance, double and triple handicaps, sensory impairment and abnormal dietary patterns. There were significantly higher contents of lead compared with normal group, except the latter two groups. The disease conditions of mentally retarded children were mongolism, autism, cerebral palsy, epilepsy and microcephaly. In comparing with mongolism, significant difference were existent only on the cerebral palsy and group of unknown etiology. We attempted to divide their past history into external etiology and internal etiology, but could not find significant difference. In view of the whole results, the relationship between mentally-retarded children and lead was presumed to be the early time exposure rather than long interval exposure during growth and the contact opportunity was considered important subject in maternal and child health care.

Comparison of Subjective Symptoms of Fatigue and Salivary pH among Teachers between Special School and Elementary / 예방의학회지

Two hundred and fifty teachers of special school (for the disabled) and 414 elementary school teachers were selected for the targets in order to compare their degrees of fatigue symptoms and to find what kind of relationship is between subjective symptoms of fatigue and pH is the saliva. It was 30 minutes before their closing hours on April 21th, 1989 that their physical, mental and neuro-sensory symptoms and salivary pH were examined. The test results are summarized as follows: It is observed that an interrelation between subjective fatigue and pH in their saliva shows a significant relationship between physical and neuro-sensory symptoms in a sense of statistics. The rate of subjective fatigue complained by the special teachers is higher than that by the elementary teachers. In the case of salivary pH, the special teachers' is as a whole lower than the elementary teachers'. The complain rates in each item, checked of special teachers are generally higher than those of the elementary teachers. It is in the mental symptom related item that there are many sub-items which show significant difference. According to the average of salivary pH based on the degrees of complained symptoms shown in the pH related items, the salivary pH of the group with complained symptoms is lower than that of the group without complained symptoms. In the rate of complaints, by sex, both sexes of the special teachers show high ones but salivary pH is low. The complain rate of mental symptoms shown by female group from the special teacher is significantly higher(p<0.05). By age, the group in their thirties from the special teachers show the higher complain rate of mental symptoms (29.3%) and the lower salivary pH (p<0.05) than that (15.1%) of the elementary teachers belonging to the same age category. However, the special teachers in their forties show the lower complain rate of physical symptoms that of the elementary teachers (p<0.05). From the viewpoint of their working years, the special teachers below 14 years and elementary teachers above 15 years in their career show high complain rates. Among those who belong to the category of 10-14 working years, the special teachers show the higher complain rate of mental symptoms than that of their counterparts. In the case of the salivary pH, the special teachers of all working-year categories show the higher pH than that of the elementary teachers. But there is not significantly difference. From the viewpoint of sleeping hours in the previous night of the questionnaire surveyed, among those who slept for over 7 hours, the special teachers show the higher complain rate of mental symptoms with significant difference, but the lower salivary pH than that of their counterparts. From the viewpoint of their marital status, existence of disease history, the special teachers show the higher complain rate of subjective fatigue, but the lower salivary pH than that of the elementary teachers respectively. According to the above results, the special teachers generally show the higher complain rate of subjective fatigue, the lower salivary pH, and the higher complain rate of mental symptoms. To prevent the possible accumulation of mental fatigue of the special teachers, ways and means to make use of leisure time, recreational facilities are necessarily provided. Since the degree of fatigue and salivary pH have a correlation to some extent, it is necessary that further continuous studies on the correlation between the degrees of fatigue and salivary pH should be pursued.

Hair Heavy Metal Contents in Mentally Retarded Children IV: In Association with Copper / 예방의학회지

The relationship between copper content in scalp hair and mental retardation was investigated. Samples of scalp hair were collected from 297 mentally retarded children who were students in one of two schools providing special educational services, one, consisted of children living in an orphan home, the other, children living with parents. For comparison, 117 scalp hair samples were collected from the children who had got average or above average academic achievement in a regular elementary school. Hair samples were taken from the nape of the neck and the copper content was determined by an atomic absorption spectrophotometer (IL 551). There was no statistically significant difference in scalp copper levels across different age groups except female orphan group, but no trend or correlation between copper contents and age was found. The hair copper contents of the group accompanied by Down's syndrome and unknown group were significantly lower than that of control group in both sex, and in the case of accompanied by epilepsy or autism, lower than control group in male. Although the results of this study show no evidence that mental retardation has owed to copper deficiency, the possibility of copper deficiency in their fetal or infant age could not be ruled out. Thus further study is needed to determine whether mental retardation could be attributed to copper deficiency. through the examinations about their living environments, dietary pattern, eating habit and the impact of copper deficiency on brain development.