Korea needs national strategies to handle problems of Small Scale Enterprises (SSEs) systematically. Since 1993, the Korean government has begun to provide financial subsidy programs for Occupational Health Services (OHSs) in SSEs from Occupational Injury Prevention Fund. To identify the health care status in SSEs in Korea, 5, 080 factories, which had participated in the Government-funded Subsidy Program in 1997, were surveyed. The overall morbidity of the workers in these SSEs was higher than the national average for both general and occupational diseases. Based on the health examinations for occupational disease of those workers exposed to occupational hazards such as noise, dust, or solvents, we could find the industry-specific occupational disease patterns. From this result, we would plan the targeted occupational health services to specific groups. In spite that the effectiveness of this program is not completely assessed, our results indicate that it is desirable for this program to be continued in Korea. In addition, this program may be a good model for rapidly developing countries.
We used a nested case-control design with study participants sampled from two cohorts, for a total of 2, 198 elderly people 65 years or older and completed cognitive tests between 1993 and 1997, to assess the association between an individual's lifetime principal occupation and the subsequent risk of cognitive impairment. Cases consisted of 290 older adults with impaired cognitive functioning. For each case, two controls with comparable age (within 5 years) and sex frequencies were randomly sampled from the seniors free of cognitive impairment. Occupational data were collected through interviews. Individual's job content was coded into one of the occupational categories or the occupationbased social classes. Compared to those who were former legislators, government administrators, or business executives and managers, a significantly elevated risk of cognitive impairment was estimated for those who were employed as agriculture/animal husbandry/forestry/fishing workers (odds ratio (OR)=3.2), craft and related trades workers (OR=2.2), plant and machine operators and assemblers (OR=14.7), workers of elementary occupations (OR=3.2), or housekeepers (OR=2.6). We also observed health inequalities in the risk of cognitive impairment across social classes with a significant doseresponse trend in which unskilled blue-collar workers had the highest risk. After adjustment for education, we still observed an inverse relationship between risk of cognitive impairment and occupational class. This may mean that lifetime longest-held occupation is more intimately involved in the causal pathways leading to cognitive impairment. Further studies that collect information on specific work hazards would help make specific interpretations of the observed effect of lifetime longestheld occupation in early adulthood on risk of cognitive decline in late life.
To examine the effects of occupational and environmental neurotoxicants on vestibular, cerebellar and spinocerebellar functions, the following three groups of subjects were examined, using a computerized posturography with sway frequency analysis: (1) 49 male chemical factory workers exposed to lead stearate, aged 27-63 (mean 43) years, with concurrent blood lead concentrations (BPbs) of 11-113 (mean 48) μg/100 g and past mean BPbs of 7-52 (mean 24) μg /100 g; (2) 29 male sandal, shoe and leather factory workers, aged 35-73 (mean 51) years, with urinary 2, 5-hexanedione (HD) concentrations of 0.41-3.06 (mean 1.20) mg/g creatinine; and (3) 9 females, aged 19-58 (mean 29) years, who were exposed to sarin accidentally 6-8 months before the study (Tokyo Subway Sarin Poisoning, March 20, 1995) and showed plasma cholinesterase (ChE) activities of 13-95 (mean 68) IU/l on the day of poisoning. The pattern of posturographic changes in lead workers suggested that the vestibulocerebellum (lower vermis), anterior cerebellar lobe and spinocerebellar afferent pathway were asymptomatically affected; the vestibulocerebellar change reflected concurrent lead absorption and the anterior cerebellar one reflected past absorption. Similarly, vestibulocerebellar and spinocerebellar functions were affected by n-hexane in solvent workers; the effect on the vestibulocerebellar function was probably inhibited by xylene. Also, the chronic (long-term) effect on the vestibulocerebellar function persisted in acute sarin poisoning. It is thus suggested that the vesitibulocerebellar function is most sensitive to all the three chemicals examined. It appears that the computerized posturography with frequency analysis is a useful technique for assessment of vestibular, cerebellar and spinocerebellar effects in occupational and environmental health.
Anemia that accompanies lead poisoning is in part the result of various inhibitory effects of lead on heme biosynthesis. Lead also increases the rate of red blood cell destruction due to the profoundly depressed activities of erythrocyte pyrimidine 5'-nucleotidase (P5N) activities. We studied parameters of the two metabolic pathways in the workers exposed to lead to evaluate P5N in the lead exposed workers and which pathway has an effect on hemoglobin (Hb) level. 29 male workers in the secondary lead smelting as high exposure group, 46 male workers in the manufacturer of inorganic pigment as low exposure group and 56 clerical male workers from another plant as nonexposed group were studied. Activity of P5N, lead concentration in whole blood (PbB), zinc protoporphyrin (ZPP), Hb, and ferritin were determined. In the present study, P5N activity of nucleotide metabolic pathway correlated with Hb after controlling indices of iron deficiency anemia (ferritin) occurring concurrently and heme biosynthetic pathway (ZPP) in the high exposure group while heme biosynthetic pathway did not correlate with Hb after controlling other two variables in exposure groups. These findings suggest that P5N rather than heme biosynthetic pathway has a major effect on Hb level even in workers without manifest hemolytic anemia.
To examine the distribution and cardiovascular risk correlates of serum triglycerides, a cross-sectional population study based on annual health examinations at the workplace was performed in 2199 young Japanese adults aged 23 to 37 years. Triglyceride levels showed significant sex (male > female) differences, and the percentages of those with high triglycerides (≥ 150 mg/dl) were 9.4% for males and 0.8% for females. In terms of conjoint trait of dyslipidemia, 86.1% of males displayed normal levels of both triglycerides (< 150 mg/dl) and high-density lipoprotein (HDL) cholesterol (≥ 40 mg/dl), while 98.7% of females had normal values. Age- and sex-specific triglyceride levels above the 75th percentile (equivalent to 82-116 mg/dl for males and 56-63 mg/dl for females) increased the risk (odds ratio (OR)) for having obesity, hypertension, and hyperuricemia by 2.9 (95% confidence interval (CI)=2.0-4.3), 1.7 (CI=1.1-2.9), and 3.0 (CI=1.6-5.9), respectively. The respective ORs for triglyceride levels above the 75th percentile and HDL cholesterol below the 25th percentile (equivalent to 45-49 mg/dl for males and 58-63 mg/dl for females), compared with triglyceride levels the 75th percentile or less and HDL cholesterol levels the 25th percentile or more, were 8.7 (CI=5.8-12.9), 2.2 (CI=1.5-3.3), and 6.0 (CI=3.2-11.5). Our results suggest a threshold effect of triglyceride levels considered as normal on enhanced cardiovascular risk in young Japanese adults, especially in those with low HDL cholesterol levels.
The relation between exposure and sensitization or the appearance of symptoms of the eyes and airways was investigated in a cross-sectional study on 32 workers from a plant using epoxy resin with a mixture of hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) as a hardener. The main component in the hardener was HHPA, and the geometric mean concentrations of HHPA in the workplaces were extremely low (<40 μg/m3) in recent years, compared to the Occupational Exposure Limit-Ceiling for phthalic anhydride (2 mg/m3). However, specific IgE antibody to HHPA was detected in serum from 8 (25%) out of the workers: of those, 5 workers experienced symptoms of the eyes and nose during work (group sensitized symptomatic (SS)) and 3 workers did not (group sensitized nonsymptomatic (SN)). The other 24 workers had no signs of sensitization and did not complain of work-related symptoms. Based on occupational history and anamnestic data, it was concluded that one subject in the SS group and all the subjects in the SN group had been sensitized by higher exposures in the past. The symptoms of 4 subjects in the SS group occurred only when carrying out short-time, particular tasks (15-30 min) a few times a day, such as the resin mixing procedures, manual application of the resin, or opening of ovens. High peak exposures were estimated to have occurred during the particular tasks. Our results suggest that short-time peak exposures may have a great impact on the development of specific IgE or work-related symptoms. Therefore, to minimize the risk of sensitization and work-related symptoms, a reduction of exposure during particular tasks with high peak exposures, along with a decrease in mean 8-h time-weighted average exposure, should be achieved.
Two surveys, one in winter the other in summer time, examined the skin problems of the entire manual workers (N=148) from 11 small-to-medium sized fiber-glass reinforced plastics (FRP) factories located in Kyushu, Japan. The workers were exposed to unsaturated polyester resin, including styrene and auxiliary agents such as cobalt naphthenate, hardeners such as methyl ethyl ketone peroxides, glass fiber and dust including shortened glass fiber and plastic particles. Eightyseven workers (58.8%) reported having skin problems (mainly itching or dermatitis) since they started to work in FRP manufacturing and 25 workers had consulted a physician because of their skin problems; one worker was forced to take sick leave because of his severe dermatitis. History of allergic diseases and shorter occupational period (duration of employment) in a FRP factory were associated with greater probability of having a history of work-related skin symptoms. Workers in factories where dust-generating and lamination sites were located in different buildings were significantly less likely to have a history of skin problems than those in factories where the two sites were located in the same building. Of the 67 workers examined in both seasons closed to double the prevalence of dermatitis was found in summer (23.3%) than winter (13.4%).
Performance of a direct-reading handy equipment for dust counting in workroom air, PDR (MIE, USA), was field-tested in comparison with the results of low-volume air samplinggravimetry. Application in 64 workplaces of various type dust work with dust concentrations of up to 1.6 mg/m3 showed that the agreement was generally good with a correlation coefficient (r) >0.64. The calculated regression line had a slope close to one, and the intercept on the axis was next to nil, suggesting that the measurement with PDR is essentially the same with that by low-volume air sampling. Further analysis by types of dust work disclosed that the correlation was best when examined in 12 foundries with r as large as 0.95. In contrast, r was small (0.52) in 11 welding workplaces, possibly due to smaller particle size of dust generated during welding.
To establish the prevalence of skin disease among nursing home workers in southern Taiwan, dermatological examination was performed on 75 nursing home staff from 11 institutions in Tainan county. Fungal infections were the most common skin diseases identified, affecting 21.4% of all employees. Other conditions included xerosis (13.3%), scabies (10.7%) and dermatitis (8.0%). Fungus was found mainly on the feet and hands (68.7% and 31.3% of all fungal cases respectively). Most xerosis sites were identified on the lower leg (90.0% of all xerosis cases), while all workers with scabies had the disease on their forearm. Dermatitis was diagnosed predominately on the forearm (50.0% of all dermatitis cases). The prevalence of fungus and scabies was higher than other studies, while dermatitis occurred less frequently than previous reports. Although not statistically significant, we believe that wet work and occupational contact with nursing home patients may have been important risk factors for these conditions.
The purpose of this study was to understand the peculiarity of the development of Hand- Arm Vibration Syndrome (HAVS) in a subtropical area of Japan. We analyzed the medical records of 21 subjects reported by the Okinawa Labor Bureau, and tried to determine whether the warm environment has any effect on the severity of HAVS. The mean operating time of vibration tools for all the subjects was over 10, 000 hrs. Almost all the subjects from Okinawa had been working only in Okinawa. The presence of Vibration Induced White Fingers (VWF) was markedly smaller in the subjects from Okinawa as compared to those from other prefectures. The results of Cold Water Immersion Tests were similar for all subjects. Ten minutes after the Cold Water Immersion Test, themean finger skin temperature was about 19°C in all subjects. These findings suggest that not only the operating time of vibration tools but also the warm environment might have an effect on the severity of HAVS. However, the number of subjects in our study was very small. There is the need therefore for further investigations with a larger number of subjects.
In an electronics plant, a new one-component naphthalene type epoxy resin was used as an adhesive for reinforcing a circuit board. The resinous part of the adhesive consisted of diglycidyl ether of bisphenol A (DGEBA) and 1, 6-bis(2, 3-epoxypropoxy)naphthalene type epoxy resins. The hardener was methylhexahydrophthalic anhydride (MHHPA). Of 54 workers, 15 (27.8%) were diagnosed to have work-related dermatitis but were not patch tested. Therefore, it was impossible to determine the specific agent responsible for the worker's symptoms or to distinguish between allergic and irritant contact dermatitis. They worked without protective gloves until they started to develop skin symptoms. The hands were the commonly affected region (13 out of 15 cases). The latent period of dermatitis was very short (mean 2.2 weeks). Of these, 10 cases (66.7%) received medication for dermatitis, and 9 cases (60%) were transferred to other work. The work-related skin symptoms were closely related to the specific tasks, i.e., filling dispensers with the adhesive and manual application of the adhesive to a portion of a circuit board using a dispenser. For occupational hygiene reasons, contact with epoxy resins should be minimized by taking all possible measures into use, including protective gloves. Further studies are required to clarify the allergenicity of 1, 6- bis(2, 3-epoxypropoxy)naphthalene, since very little is known about the mechanism through which it leads to the symptoms of dermatitis.