Relationship between magnesium levels in drinking water and sudden infant death syndrome

The possible association between the risk of death from sudden infant death syndrome (SIDS) and the levels of magnesium in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Characteristics for all SIDS deaths (501 cases) among Taiwan residents from 1988 through 1997 were compared with those of people who died from other causes (501 controls). The levels of magnesium in the drinking water of these residents were determined from data obtained from the Taiwan Water Supply Corporation (TWSC). The controls were pair-matched to the SIDS cases by sex, month and year of birth. The results of our study show that there is a significant trend towards a decreased risk of SIDS with increasing magnesium levels in drinking water.

Increased risk of preterm delivery in areas with air pollution from a petroleum refinery plant in Taiwan

The petrochemical and petroleum industries are among the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to a petroleum refinery plant. The prevalence of delivery of preterm birth infants was significantly higher in mothers living in a petroleum refinery area compared to controls in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.41 (95% CI = 1.08-1.82) for delivery of preterm infants in the polluted region. Data support the view that air pollution can affect the outcome of pregnancy.

Obstructive pulmonary function defects among Taiwanese firebrick workers in a 2-year follow-up study

The purpose of the study was to follow up an earlier observation of pulmonary function among workers employed in firebrick-manufacturing factories. A 2-year follow-up study of pulmonary function among 442 workers in 30 firebrick-manufacturing factories was designed. Excluding 79 workers with a history of other occupational dust exposure, changes in pulmonary function of 291 firebrick workers were compared with pulmonary function in 72 control subjects over a period of 2 years. Baseline pulmonary function values (i.e., forced expiratory volume in 1 second [FEV1]/forced vital capacity [FVC] and forced expiratory flow after 50% of vital capacity has been expelled [FEF50%] in smoking firebrick workers, and FEV1/FVC and FEF75% in nonsmoking firebrick workers) were significantly lower than those in the comparison group. The statistical method for repeated measurements was used for comparison of the difference between follow-up and baseline lung function. There was no significant difference in FVC and FEV1 changes between firebrick workers and those in the comparison group during the 2-year follow-up period. The decreases in FEV1/FVC, peak expiratory flow rate, maximal midexpiratory flow, and FEF50% in the firebrick workers were significantly greater than in the comparison group, after adjustment for smoking status. The FEV1, maximal midexpiratory flow, FEF50%, and FEF75% also showed a dose-response relationship with job titles. The decrement of pulmonary function in the 2-year follow-up period was the worst in burning work, followed by crushing and molding. The results show that workers in firebrick-manufacturing factories with exposure to silica-containing dusts may contract obstructive pulmonary function defects.

Adverse pregnancy outcome in a petrochemical polluted area in Taiwan

The petrochemical industry is the main source of industrial air pollution in Taiwan. Reported here are the results from an ongoing study of outdoor air pollution and the health of individuals living in a community in close proximity to petrochemical industrial complexes. The prevalences of term low birth weight (LBW) in the petrochemical municipality and control municipality were 3.22%, and 1.84%, respectively. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.767 (1.002-3.116) for term LBW in the petrochemical municipality. Data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.

A pilot evaluation of tibia lead concentrations in Taiwan

BACKGROUND

The aims of this study were to examine some of the factors that influence tibia lead concentrations, tibia lead x-ray fluorescence measurement uncertainty and blood lead concentrations, and to compare tibia lead concentrations in Taiwanese lead workers to those observed in lead workers from other countries.

METHODS

A pilot evaluation of 43 adult lead workers who underwent measurements of tibia lead and blood lead concentrations.

RESULTS

Mean and maximum tibia lead concentrations were 54 microg of Pb per g of bone mineral(microg/g) and 193 microg/g, respectively. Mean and maximum blood lead concentrations were 44 microg/dl and 92 microg/dl, respectively.

CONCLUSION

Past occupational control of lead exposure in Taiwan, ROC, did not prevent these workers from accumulating tibia lead concentrations greater than those in similar workers elsewhere in the world.

Carbon disulfide vasculopathy: a small vessel disease

We present the clinical manifestations of 4 male patients with acute stroke-like symptoms and polyneuropathy after long-term exposure to carbon disulfide (CS2) in a viscose rayon plant. The ages of onset of polyneuropathy ranged from 42 to 45 years with a duration of CS2 exposure between 6 and 21 years. The ages of onset of stroke were from 42 to 48 years. The risk factors for stroke including heart disease and diabetes were denied, except for smoking in 4, hyperlipidemia in 2 and hypertension in 1. At the initial visit in 1992, only 2 patients developed sudden onset of hemiparesis suggesting a lacunar stroke before the diagnosis of CS2 intoxication. Brain computed tomography (CT) scans showed low-density lesions in the basal ganglia in 2 patients, cortical atrophy in 1 and normal in 1. Brain magnetic resonance image (MRI) study disclosed multiple lesions in the corona radiata and basal ganglia on T(2)-weighted images in 3 patients and cortical atrophy in 1. After the diagnosis, they left their jobs for a CS2-free environment, and improvement of the working conditions was noted. During 5 years follow-up period, another 2 patients also developed an acute episode of stroke with hemiparesis. Brain CT and/or MRI follow-up studies in these 2 patients revealed new lesions in the basal ganglia and corona radiata. Intriguingly, a patient with previous stroke also developed new lesions in the bilateral thalami and brainstem. Carotid Doppler scan, transcranial Doppler scan and/or cerebral angiography did not show any prominent stenosis or occlusion in the major intracranial large arteries. We conclude that encephalopathy may occur in patients after long-term CS2 exposure, probably due to impaired cerebral perfusion. The lesions tend to occur in the basal ganglia, corona radiata and even brainstem, particularly involving the small-sized vessels. In addition, the cerebral lesions may progress even after cessation of CS2 exposure. Therefore, we suggest that CS2 exposure may be a risk factor for stroke.

Adverse health effects among household waste collectors in Taiwan

Household waste collectors (HWCs) are potentially exposed to a variety of bioaerosols and toxic materials. Collection of household waste is also a job which requires repeated heavy physical activity such as lifting, carrying, pulling, and pushing. The object of this study was to assess whether there is an excess of adverse health outcomes among HWCs. The subjects were all current employees of the Household Waste Collection Department in the County of Kaohsiung, Taiwan. The survey questionnaire was completed by 533 HWCs and 320 office workers. Our data indicate that household waste collection presents a risk for the development of chronic respiratory symptoms (cough, phlegm, wheezing, and chronic bronchitis), musculoskeletal symptoms (low back pain and elbow/wrist pain), and injuries caused by sharp objects.

Chlorination of drinking water and sex ratio at birth in Taiwan

Chlorination has been the major strategy for disinfecting drinking water in Taiwan. The objective of the present study was to determine whether the chlorination of drinking water was associated with abnormal sex ratios, an indicator of exposure to pollutants. A "chlorinating municipality" (CHM) was defined as one in which more than 90% of the municipality population was served with chlorinated water. A "nonchlorinating municipality" (NCHM) was one in which less than 5% of the municipality population was served with chlorinated water. The results of this study found no association between the use of chlorinated drinking water and abnormal sex ratios at birth in Taiwan. The imbibing of chlorinated water may not reflect contaminant exposure using sex ratio as a biomonitor.

Association between chlorination of drinking water and adverse pregnancy outcome in Taiwan

Chlorination has been the major means of disinfecting drinking water in Taiwan. The use of chlorinated water has been hypothesized to lead to several adverse birth outcomes, including low birth weight and preterm delivery. We performed a study to examine the relationship between the use of chlorinated water and adverse birth outcomes in Taiwan. The study areas included 14 chlorinating municipalities (CHMs), which were defined as municipalities in which > 90% of the municipal population was served by chlorinated water, and 14 matched nonchlorinating municipalities (NCHMs), defined as municipalities in which < 5% of the municipal population is served by chlorinated water. The CHMs and NCHMs were similar to one another in terms of level of urbanization and sociodemographic characteristics. The study population comprised 18,025 women residing in the 28 municipalities who had a first parity singleton birth between 1 January 1994 and 31 December 1996 and for which complete information on maternal age, education, gestational age, birth weight, and sex of the baby were available. The results of our study suggest that there was no association between consumption of chlorinated drinking water and the risk of low birth weight.

Calcium and magnesium in drinking water and the risk of death from breast cancer

The relationship between mortality from breast cancer and the levels of calcium and magnesium in drinking water was examined using an ecological design. The study area consisted of 2.52 municipalities in Taiwan. Data on the levels of calcium and magnesium in drinking water were collected from the Taiwan Water Supply Corporation (TWSC). The age-standardized mortality rate (ASR) for breast cancer ( 1982-1991) was compared among municipalities with different levels of magnesium and calcium in drinking water. Weighted multivariate regression analysis was used, and after adjusting for fertility rates and urbanization, there was a significant inverse relationship between the levels of calcium and magnesium in drinking water and risk of death from breast cancer.

Female lung cancer mortality and sex ratios at birth near a petroleum refinery plant

This study was conducted to assess whether female mortality from lung cancer is associated with residence in communities adjacent to a petroleum refinery plant and whether petroleum air pollution could affect the sex ratios of births. The Kaohsiung Refinery of the Chinese Petroleum Corp. is the oldest oil refinery in Taiwan and is located between the Tso-Ying and the Nan-Tzu municipalities. Standardized mortality ratios (SMRs) for female lung cancer and sex ratios of births were calculated for each municipality for the years 1971-1996. Cumulative-sum techniques were used to detect the occurrence of changes in the SMRs. The study results show that mortality from female lung cancer rose gradually about 30 to 37 years after the operation of a petroleum refinery plant began. However, the association between exposure to the petroleum air pollution and abnormal sex ratios at birth was not significant.

Effects of lead and noise exposures on hearing ability

Lead and noise, via different mechanisms, may damage hearing ability, and, in some cases, cause severe and irreversible damage. To explore possible independent and synergistic effects of lead and noise on auditory function, the authors conducted a cross-sectional study in two lead-battery manufacturing factories. Lead and noise were the two most common sources of occupational exposures in the factories. Blood lead level, ambient lead concentration, noise exposure level, and hearing thresholds of 339 lead-battery workers-including clerical and managerial staffs-were measured. The authors obtained demographics and working histories via an interview-based structured questionnaire. A total of 220 lead-battery workers were exposed to high levels of lead and noise; their average blood lead concentration was 56.9 microg/dl, and their average noise exposure level was 86.0 dBALeq. Multivariate analysis, in which possible risk factors of hearing ability were considered, demonstrated a significant correlation between a high, long-term lead exposure index (defined by duration of employment and ambient lead concentration) and decreased hearing ability. In contrast, such a correlation between short-term lead exposure (defined by blood lead level) and hearing ability was not significant. Furthermore, neither noise exposure level alone nor the interaction between noise exposure level and short- or long-term lead exposure was correlated significantly with hearing ability. The present study raises an important, but typically ignored, issue: lead exposure might precipitate a more severe auditory than noise-exposure effect. The preservation of workers' hearing ability requires that preventive measures be taken against noise exposure, which is as essential as measures taken against lead exposure.

Hantavirus infection in Taiwan: the experience of a geographically unique area

Hantaviruses are rodent-borne viruses, and they, mainly the Hantaan (HTN) serotype, are the causative agents of a group of febrile nephropathies known as "hemorrhagic fever with renal syndrome (HFRS). " Despite the fact that HFRS is frequently reported in China, with an annual incidence of 50,000-100,000 cases, one puzzling observation that no local case of HFRS has been confirmed in Taiwan has yet to be explained. We hypothesized that the hantavirus strain prevailing in Taiwan mainly belongs to the mild strain, the Seoul (SEO) strain, and the absence of severe disease was related to the absence of HTN. To test these hypotheses, this epidemiologic study was performed, including a seroprevalence survey and phylogenetic analysis on hantavirus isolated from the rodent population trapped in major seaports, rural, and mountainous areas of Taiwan. This study also included rodents and viruses from two isolated islands, Kinmen and Matzu, which are geographically adjacent to the east coast of mainland China. There were a total of 5,461 rodents of 16 species captured, and R. norvegicus was the most common species, with an antibody prevalence much higher in international seaports (20%) than in rural regions (approximately 5%) and intermediate in some domestic seaports. By reverse transcriptase polymerase chain reaction (RT-PCR), 33.9% of the seropositive R. norvegicus were found to have amplifiable hantavirus sequences in their lung tissues, and subsequent phylogenetic analyses indicated that almost all hantavirus in Taiwan was most closely related to the prototype SEO strain, and no HTN strain was recovered from any rodent species indigenous to Taiwan. The seroprevalence of SEO infection in R. norvegicus on Kinmen and Matzu was also different from that in southern provinces of China but closely resembled that in seaports in Taiwan, and the SEO identified was genetically linked to Taiwanese SEO strains. These results substantiate our hypotheses, and suggest that the epidemiology of hantavirus infection in Taiwan are different from that in China, where the HTN and SEO strains and HFRS concurrently prevail.

Association between aminolevulinate dehydrogenase genotype and blood lead levels in Taiwan

This study was designed to evaluate the association between the aminolevulinate dehydrogenase (ALAD) genotype and blood lead levels in a general population environmentally exposed to lead. This study population of 660 subjects was secondarily sampled from the 3000 random samples of Taiwanese general population to study the distribution of blood lead levels in the Taiwanese population. A simple assay based on the polymerase chain reaction-restriction fragment length polymorphism technique was used to determine the genotype of the ALAD gene. This study found that most of the Taiwanese population was ALAD 1-1 (95.4%). Only 4.6% (30 subjects) of population were found to be 1-2 or 2-2. It has been hypothesized that the ALAD2 allele is associated with increased absorption of lead. This study found that individuals with ALAD2 alleles had 20% higher blood lead levels than persons with ALAD1 alleles (7.83 +/- 5.95 vs 6.51 +/- 5.03 micrograms/dL). However, the difference was not statistically significant, even after adjustment for other risk factors of environmental exposure. The result supports the previous finding that individuals with ALAD2 allele had higher blood lead levels. The small sample size and large amount of variation in our study may account for the insignificant association.

Increased chromosome-type chromosome aberration frequencies as biomarkers of cancer risk in a blackfoot endemic area

To examine whether biomarkers such as sister chromatid exchanges (SCEs) and chromosome aberrations (CAs) can predict cancer development, a nested case-control study was performed in a blackfoot endemic area with a known high cancer risk. A cohort of 686 residents was recruited from three villages in the blackfoot endemic area. Personal characteristics were collected, and venous blood was drawn for lymphocyte culture and stored in a refrigerator. The vital status and cancer development were followed using the National Death Registry, Cancer Registry, and Blackfoot Disease Registry. The follow-up period was from August 1991 to July 1995. During this 4-year period, 31 residents developed various types of cancer. Blood culture samples from nine of these subjects were unsuitable for experiments due to improper storage. Finally, a total of 22 cancer cases had cytogenetic samples that could be analyzed. Twenty-two control subjects were selected from those who did not develop cancer in the study period, and these subjects were matched to cases by sex, age, smoking habits, and residential area. The results showed that there was no significant difference in the frequencies of SCE and chromatid-type CAs between the case and control groups. However, the frequencies of chromosome-type CAs, e.g., chromosome-type gaps, chromosome-type breaks, chromosome-type breaks plus exchanges, total chromosome-type aberrations, and total frequencies of CAs in the case group, were significantly higher than those in the control group (P < 0.05). The odds ratio of cancer risk in subjects with more than zero chromosome-type breaks was 5.0 (95% confidence interval = 1.09-22.82) compared to those with zero chromosomal breaks. The odds ratios for more than zero chromosome-type breaks plus exchanges and a frequency of total chromosome-type aberrations of >1.007% were 11.0 and 12.0, respectively (P < 0.05). Subjects with a total CA frequency of >4.023% had a 9-fold increase for cancer risk. These results indicate that chromosome-type CAs are good biomarkers for the prediction of cancer development, whereas SCEs and chromatid-type CAs cannot predict cancer risk.

Reappraisal of the relation between blood lead concentration and blood pressure among the general population in Taiwan

OBJECTIVES

The relation between blood lead concentration (PbB) and blood pressure was examined in a Taiwan nationwide population survey of PbB from July 1993 to June 1994.

METHODS

After multistage sampling procedures, 2800 subjects (1471 males and 1329 females) with a mean (range) age of 44 (15-85) years were enrolled in this study. Anthropometric, blood pressure, and lifestyle factors were measured during household visits. The PbB was measured with a flameless atomic absorption spectrophotometer and all specimens were analysed in triplicate.

RESULTS

The mean (range) PbB among all study subjects was 6.5 (0.1-69.1) micrograms/dl; among males it was 7.3 (0.1-69.1) micrograms/dl and among females 5.7 (0.1-40.1) micrograms/dl). The mean (range) systolic blood pressure among all subjects was 123 (80-210) mm Hg, among males it was 127 (80-200) mm Hg and among females 119 (80-210) mm Hg. The diastolic blood pressure among all subjects was 78 (40-150) mm Hg; among males it was 80 (40-130) mm Hg; and among females 75 (40-150) mm Hg. Age, body height, body weight, and body mass index (BMI) were significantly correlated with systolic blood pressure or diastolic blood pressure in both sexes. The PbB (or the natural logarithmic transformed PbB) was not significantly correlated with blood pressure among males or females. After adjustment for the potential confounders of age, age2, BMI, milk intake, alcohol consumption, and cigarette smoking, systolic blood pressure was significantly associated with PbB among males with a regression coefficient (beta) of 0.185 (p = 0.015). No significant association between PbB and blood pressure was found among females.

CONCLUSIONS

From this study, only a weak association between systolic blood pressure and PbB was found among males. There was no strong evidence that PbB was a good predictor of blood pressure. However, the possibility that long term high body lead burden could cause high blood pressure could not be ruled out on the basis of this survey.

Sentinel surveillance for enterovirus 71, Taiwan, 1998

Outbreaks of enterovirus 71 have been reported around the world since 1969. The most recent outbreak occurred in Taiwan during April-July 1998. This hand, foot, and mouth disease epidemic was detected by a sentinel surveillance system in April at the beginning of the outbreak, and the public was alerted.

Chronic inorganic mercury induced peripheral neuropathy

We report the clinical features, electrophysiological studies, and morphometric analysis of sural nerve pathology in a patient with polyneuropathy due to inorganic mercury intoxication. He developed slowly progressive generalized paralysis of all limbs after 3 months ingestion of herb drugs which contained mercuric sulfate. Electrophysiologic studies revealed axonal polyneuropathy involving both motor and sensory fibers. Sural nerve biopsy demonstrated axonal degeneration with demyelination and a predominant loss of large myelinated fibers. His muscle strength showed only mild improvement after 2 years' follow-up. We concluded that inorganic mercury exposure may induce severe axonal sensorimotor polyneuropathy in humans and that neurological deficits may persist in severe cases.

Risk factors for high blood lead levels among the general population in Taiwan

PURPOSE

Environmental and occupational lead pollution is a common problem in both developing and industrialized countries. The purpose of this study is to evaluate the risk factors for high blood lead levels among the general population in Taiwan.

METHODS

After multi-stage sampling, we randomly selected 2803 subjects (1471 males and 1332 females) for this study. Univariate and multivariate logistic regression analyses were conducted to evaluate the risk of high blood lead. To control for differences in age and gender, all analyses were with age-adjusted and gender-stratified.

RESULTS

Among males, the mean age is 46 years (15 to 85 years), mean and median blood lead levels is 7.3 and 6.3 microg/dl, respectively. Among females, the mean age is 43 years (15 to 84 years), mean and median blood lead level is 5.7 and 4.8 microg/dl, respectively. Among males, the history of herbal drug use, drinking water from well or spring sources, and occupational lead exposure are significantly different between relatively high and normal blood lead level subjects. The history of occupational lead exposure, history of herbal drug use, and well or spring sources of drinking water are the major risk factors for high blood lead with odds ratio of 4.62 (95% CI: 2.82-7.55), 3.09 (95% CI: 1.60-5.97), 2.06 (95% CI: 1.13-3.76), and 2.37 (95% CI: 1.39-4.04), respectively. Among females, these characteristics remain important except the sources of drinking water. The history of herbal drug use and occupational lead exposure become the major risk factors for high blood lead with odds ratio of 2.94 (95% CI: 1.26-6.88) and 7.72 (95% CI: 3.51-16.99), respectively. In multivariate logistic regression analyses, we find that the risk factors for high blood lead in both genders include a history of herbal drug use and occupational lead exposure. Among males, the drinking water sources and factories in the neighboring areas are also significant factors for high blood lead.

CONCLUSIONS

For the goal of reducing prevalence of high blood lead by the year 2000, the improvement and monitoring of the working environment, the careful attention to herbal drug use and the lead-free drinking water sources should be executed as thoroughly as possible to reduce the probability of lead pollution.

Lyme disease in Taiwan: first human patient with characteristic erythema chronicum migrans skin lesion

We report herein the first laboratory-diagnosed case of Lyme disease in a human in Taiwan. A 45-year-old Taiwanese man living in Taipei, in northern Taiwan, had an expanding skin lesion (measuring 23 by 15 cm) on his abdomen for 2 to 3 weeks and recurrent attacks of pain and swelling of the knee joint. Serologic tests indicated a significantly elevated titer of antibody to Borrelia burgdorferi. After appropriate antibiotic treatment for 3 weeks, the skin lesion was cured and the joint swelling was improved. Although several strains of Borrelia spirochetes had been isolated from rodents (Rattus losea) in Taiwan, the tick vector responsible for the transmission remains to be identified.

Surveillance of noise-induced hearing loss in Taiwan, ROC: a report of the PRESS-NHL results

BACKGROUND

To understand the extent of noise-induced hearing loss (NIHL) among noise-exposed workers, an ongoing public health surveillance system (Program to Reduce Exposure by Surveillance System or PRESS-NIHL) was established in Taiwan in 1995 to monitor the prevalence of NIHL.

METHODS

A total of 9,535 noise-exposed (> 85 dBA) workers were recruited into PRESS-NIHL from January to June 1995. Each received a periodic annual audiometric examination at 1 of 73 well-qualified audiometric examination rooms in accredited hospitals. Among those examined, 9,463 audiograms were acceptable for evaluation to determine the severity of NIHL at 4K Hz.

RESULTS

The mean hearing threshold at 4K Hz was 36.8 dB among male workers and 29.7 dB among female workers. The mean hearing loss at 4K Hz of male workers was higher than that of female workers. Among both men and women, hearing ability was found to decrease with increasing age. A total of 3,216 (34.0%) workers were found to have NIHL, with a hearing threshold higher than 40 dB (NIHL) in either one or both ears. Among these workers, 1,886 (19.9%) had mild NIHL (hearing threshold between 40 and 55 dB) and 1,330 (14.1%) had severe NIHL (hearing threshold above 55 dB) in either one or both ears. The proportion of severe NIHL was higher in certain industries, including construction (38.6%), ship building/repairing (19.2%), and weapon manufacturing (13.6%).

CONCLUSION

This surveillance system for NIHL is on of the first surveillance systems in the world established to monitor and control NIHL in the setting of industrial hygiene and occupational disease prevention. Our finding of a high prevalence of NIHL in certain industries will trigger immediate actions to control noise hazard, which in turn will provide better protection for noise-exposed workers.

Reducing lead exposure by surveillance system: the Taiwan experience

To evaluate the performance of a lead-surveillance program in reducing blood lead levels of workers in Taiwan, the authors conducted prospective and cross-sectional studies. A total of 6 905 workers, whose job titles indicated a direct exposure to lead in 1995, were included in this surveillance system. In this study, the authors compared the mean blood lead levels in 1994 (i.e., year of onset of surveillance) with that in 1995 in workers of major industries. Lead-exposed workers had a statistically significant decrease (i.e., average of 1.8 microg/dl) in blood lead levels during this 1-y period. The decrease was particularly obvious in individuals who worked in chemical products manufacturing, ship building/repairing, and plastic products manufacturing. The significant decreases in blood lead levels in these workers indicated that this surveillance system was effective. Surveillance, combined with control measures, might be an important means by which occupational lead exposure can be reduced.

Occupational neurotoxic diseases in Taiwan: a review of the outbreaks and clinical features

In the past 20 years, several outbreaks of neurotoxic disease due to occupational exposure have occurred in Taiwan. The most notorious outbreaks were 'Yu-cheng' due to contamination of polychlorinated biphenyls in cooking oil, lead poisoning in battery manufacturers and workers in a ship-scrapping yard, tile factory and battery recycling plants, and n-Hexane intoxication in press-proffers and ball-manufacturers. In addition, there were manganese intoxication in ferromanganese smelters, mercury intoxication in lamp-socket workers, carbon disulfide intoxication in viscose rayon workers and hydrogen sulfide intoxication in chemical synthetic plants. Although the incidence of occupational neurotoxic diseases has increased, the real incidence is probably still underestimated. The reasons for the underestimation include: 1) the education for workers in industrial hygiene is inadequate; 2) high risk workers are not screened well; 3) physicians are not well trained in early diagnosis of occupational diseases; 4) material safety data information is not readily available in the factories; and 5) the threshold limit values for toxic substances are relatively high in Taiwan, compared with other developed countries.

Epidemiologic study of occupational injuries among foreign and native workers in Taiwan

This study was designed to compare the risk of occupational injuries in foreign workers compared to native workers in Taiwan. The cohort of foreign workers under study was constructed by records of legally registered workers migrated from foreign countries to Taiwan from July 1, 1991 to December 31, 1993. The native Taiwanese workers for comparison were labor-insured workers working in the same industries as foreign workers in 1992. The number of occupational injuries in the first year of employment were obtained by matching the cohort of foreign workers with the labor insurance payment records by name, birth date and passport number. The 1-year incidence rate of occupational injuries in the first year of employment was calculated and a standardized morbidity ratio (SMR) was used for comparison with adjustment for age distribution and to accommodate the small sample size of foreign workers. The risk to occupational injuries among total (SMR = 0.86) and male (SMR = 0.58) foreign workers was not higher; indeed, it was even lower, than that among native workers in Taiwan. However, the risk to female migrant workers, especially in the construction industry, was significantly higher than that of female Taiwanese workers (SMR = 1.60). Stratified by industry, the incidence was high in the fabricated metal products manufacturing industry and in machinery and equipment manufacturing industry for male foreign workers, while a high incidence for the female foreign workers occurred in construction industry and rubber products manufacturing industry. The risk of occupational injuries was greater for foreign workers who had been in Taiwan for only a short time. Most of the injuries occurred within the first 6 months of employment. Eighty-four out of the 394 occupational injuries among foreign workers resulted in disabilities. None of the accidents was fatal, but most of the disabilities were severe. The most common disabling injuries were cut or crushed fingers. The finding of a similar distribution of occupational injuries among foreign and native workers indicates that control measures are needed to reduce occupational injuries for all foreign and native workers in Taiwan.

The epidemiology and surveillance of blood lead in Taiwan (ROC): a report on the PRESS-BLL project

To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July 1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 micrograms/dl in male workers and 11.6 micrograms/dl in female workers. The mean BLL of lead-exposed workers was significantly (P < 0.05, z-test) higher than that of the general Taiwanese population (8.6 micrograms/dl for males and 6.7 micrograms/dl for females). In addition, the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 micrograms/dl for males; 30 micrograms/dl for females). The workplaces and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination. These actions identified the causes of elevated BLLs and set up strategies to reduce workers' lead exposure. The establishment of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae.

A study of the relationship between ambient lead and blood lead among lead battery workers

OBJECTIVE

To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead.

METHOD

A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history.

DESIGN

Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation.

RESULTS

A high correlation (r = 0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions.

CONCLUSION

Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories.

Establishment of a work-related diseases surveillance system in Taiwan, Republic of China

BACKGROUND

The occurrence of occupational illness and injury has been seriously underestimated in Taiwan, which subsequently contributes to difficulties in performing effective control of occupational hazards and implementing intervention programs for protecting workers.

METHODS

Based on the successful experience of the nationwide blood lead level surveillance program, the Department of Health, the Executive Yuan, Taiwan, Republic of China, has established a work-related diseases surveillance system. This government-administered system requests practicing physicians to report the suspected cases suffering from six categories of work-related disorders.

RESULTS

An occupational illness and injury surveillance program in Taiwan has been in operation since June of 1995.

CONCLUSION

Background information of work-related diseases obtained from this surveillance system will be useful for providing better management of available resources for occupational medicine, for preventing hazards, and for enforcing occupational diseases prevention programs. Our experience in establishing this surveillance system will be used in other countries and settings.

Survey on the distribution of Vibrionaceae at the seaport areas in Taiwan, 1991-1994

A monthly survey on the distribution of human-pathogenic Vibrionaceae of the seawater from five principal harbors in Taiwan was conducted by National Quarantine Service from July, 1991 to February, 1994. Of the total 1,167 Vibrionaceae isolates, strains of Vibrio alginolyticus (449 strains) were the most frequently isolated, followed by Vibrio parahaemolyticus (262) , Aeromonas hydrophila (153), Vibrio cholerae non-O1 (86), and Vibrio vulnificus (67). None of Vibrio cholerae O1 was isolated. The pH, salinity, and water temperature in this study ranged from 5.8 to 8.6, 0.1 to 4.2% , and 15 to 34 degrees C, respectively. It is concluded that the family Vibrionaceae exists autochthonously around the coastal waters in Taiwan.

Carbon disulfide induced polyneuropathy: sural nerve pathology, electrophysiology, and clinical correlation

We report the clinical features, electrophysiological studies, sural nerve pathology and recovery course of carbon disulfide-(CS2) induced polyneuropathy in a 48-year-old man who worked in a viscose rayon plant. Sural nerve biopsy 2 years later still showed degeneration of both axon and myelin with a predominant loss of large myelinated fibers and remyelination. Electrophysiologic studies revealed mixed axonal and demyelinating polyneuropathy. To our knowledge, this is the first human report of sural nerve pathology in the recovery stage due to CS2 intoxication. After diagnosis, the patient was removed from the toxic environment. In the following three years, he showed part recovery predominantly in motor function compatible with the serial nerve conduction studies. We conclude that CS2 polyneuropathy may partly recover years after cessation of exposure.

Occupational lead exposure and blood pressure

BACKGROUND

To assess the relation between occupational lead exposure and elevated blood pressure with consideration of a possible confounding effect by noise exposure.

MATERIALS AND METHOD

Some 112 male and 110 female workers at two lead battery manufacturing factories were recruited for this 1992 study in Taiwan. Study participants received regular physical examinations, including standard measurement of blood pressure, body height/weight. Current occupational exposures to lead and noise were measured by a personal sampling scheme and instruments, and included individual ambient lead/noise exposure and blood lead level.

RESULTS

Among the 222 battery-factory workers, the average blood lead level was 56.9 +/- 25.5 micrograms/dl (mean +/- standard deviation), the average concentration of ambient lead exposure was 0.190 +/- 0.331 mg/m3, average noise exposure was 85.9 +/- 5.7 dBA, average systolic blood pressure was 125.2 +/- 14.9 mmHg, average diastolic pressure was 80.2 +/- 10.9 mmHg, and average mean arterial pressure was 95.2 +/- 11.1 mmHg. After considering all possible confounding variables, multivariate regression analyses demonstrated that current blood lead level was not a significant predictor for both systolic and diastolic blood pressures in either sex. In the final model, body mass index and years of working in the factory were the only two factors significantly associated with a change in blood pressure. No evidence of an effect of ambient lead exposure or noise exposure on blood pressure were found.

CONCLUSIONS

The present study suggests that short-term lead exposure, either ambient lead exposure or blood lead level, was not related to blood pressure change among workers who had been exposed at work to occupational lead. These results add to the body of evidence indicating that blood lead exposure does not adversely affect blood pressure.

Prospective study of noise exposure during pregnancy on birth weight

To examine the effect of noise exposure during pregnancy on infant birth weight, a well-characterized cohort of 200 pregnant women in the first trimester participating in prenatal care clinics was followed throughout gestation (in Taiwan, 1991). Individual 24-hour noise exposure of all women was prospectively measured, and information regarding possible noise exposure from traffic and occupation was also obtained. Noise exposure during pregnancy was correlated with the birth weights of the women's babies. No association between personal noise exposure measured in decibels (less than 85 dBALeq during pregnancy) and birth weight was found. Possible occupational noise exposure (indicated by working in a manual job), traffic noise exposure (indicated by distance between the home and main streets), and a history of listening to amplified music and using personal listening devices during pregnancy also showed no effect on infant birth weight. Maternal weight, maternal weight gained during pregnancy, gestational age, and infant's sex were the four factors that correlated significantly with birth weight. The noise exposure experienced by women during pregnancy may not be great enough to affect their infants' birth weight.

Lead poisoning caused by contaminated Cordyceps, a Chinese herbal medicine: two case reports

Two cases of lead poisoning, caused by the Chinese herbal medicine Cordyceps, were reported to the Department of Health in a laboratory-based blood lead surveillance program. Such unusual cases of lead poisoning have not been previously reported. These two patients took Cordyceps herbal medicine for treatment of underlying diseases. Loss of appetite and anemic signs of lead poisoning were manifested in one patient with a blood lead level of 130 microg/dl, while the other patient was asymptomatic with a blood lead level of 46 microg/dl. The lead content in the Cordyceps powder was found to be as high as 20 000 ppm. After cessation of intake in the asymptomatic patient, and cessation of intake and treatment with chelating agents in the symptomatic patient, the blood lead levels returned to normal range. This report raises concerns about lead poisoning from unusual herbal medicine worldwide.

Blood lead levels in Taiwanese adults: distribution and influencing factors

Five-thousand nine-hundred thirteen Taiwanese adults were selected by multistage sampling methods to investigate environmental lead exposure in Taiwan. The blood specimens were distributed to six laboratories for blood lead levels (BLL) measurement. The mean BLL of the 5913 Taiwanese adults was 8.28 +/- 5.39 microg/dl, with a maximum level of 57.6 microg/dl. The median was 7.0 microg/dl and 90th percentile was 15.0 microg/dl. BLLs were associated with gender, ethnic group, education level, smoking, alcohol consumption, herbal drug consumption, milk consumption, sources of drinking water, level of urbanization, and occupational lead exposure. These results showed that BLLs in Taiwanese adults were stable during the 2-year study. Most of the influencing factors were consistent with other studies, while local risk factors, such as Chinese herbal drug consumption are important ways of preventing the general population from overexposure to lead.

Acute health hazards of firefighters after fighting a department store fire

The purpose of this study was to evaluate the health hazards of firefighters after fighting a department store fire which lasted for 40 hours. Respiratory symptoms of 168 firefighters were collected and the pulmonary functions of 149 firefighters were measured by spirometer two days after fighting the fire and compared to 32 controls. The principal symptoms manifested by firefighters were burning eyes and mucous membrane irritation. Cross-sectional study of the pulmonary functions showed that FEV1.0, FEV1.0/FVC and the flow rates (MMF, FEF25%, and FEF75%) in smoking exposed firefighters were significantly lower than those in smoking controls. However, only FEV1.0 (%) was significantly lower in nonsmoking exposed firefighters than in nonsmoking controls. Both FVC and FEV1.0 showed a declining trend with the duration of fire fighting. This study provides further evidence that firefighters are exposed to irritants during fighting a fire. Exposure to the combustion products could lead to pulmonary function defects, especially in smoking firefighters.

Three-year survey of blood lead levels in 8828 Taiwanese adults

The purpose of this study was to investigate environmental lead exposure in the general Taiwanese population. A total of 8828 Taiwanese adults selected by a multistage sampling method were investigated. Characteristics of the participants were ascertained by questionnaire and 10 ml venous blood was drawn by public health nurses. The blood specimens were distributed to six laboratories for blood lead level (BLL) measurement. A quality control program was applied during the analysis of the BLLs in order to improve precision and accuracy. The arithmetic mean BLL of the 8828 Taiwanese adults was 7.70 +/- 5.23 micrograms/dl, with a maximal level of 69.1 micrograms/dl. The median was 6.5 micrograms/dl and the 90th percentile was 14.0 micrograms/dl. After logarithmic transformation, the geometric mean was 1.84 +/- 0.67 microgram/dl. This study also found that elevated BLLs were associated with certain personal characteristics, i.e., gender, ethnic group, and education level; life-style factors, such as smoking, alcohol consumption, Chinese herbal drug consumption, milk consumption, and sources of drinking water; residential location, i.e., level of urbanization; and occupational history of lead exposure. However, age, floor level of residence, distance from house to road, and betel nut consumption were not associated with elevated BLLs. These results showed that BLLs in the Taiwanese population were not higher than those in developed and developing countries. Most of the influencing factors were also found in other studies; however, local factors such as ethnic group, Chinese herbal drug consumption, and sources of drinking water are important considerations in Taiwan when examining ways to prevent overexposure to lead in the general population.

Molecular epidemiological studies of Vibrio cholerae in Taiwan: genotyping by polymerase chain reaction and DNA sequencing

To type the Vibrio cholerae strains isolated from sporadic and epidemic cases in Taiwan, 28 toxigenic isolates were studied by sequencing polymerase chain reaction-amplified cholera toxin gene (ctx) fragments. Based on specific base substitutions on positions 115 and 203 of ctxB and comparison with previously published typing system from Centers for Disease Control and Prevention (Olsvik theta et al., J Clin Microbiol 1993; 31:22-5, Ref.1), two genotypes were identified. Cholera strains from imported seafood and sporadic cases in Taiwan had ctxB polymorphism of genotype 1; strains from patients in the 1962 Taiwan epidemic and Taiwan raised soft-shell turtles had ctxB polymorphism of genotype 3. Moreover, one toxigenic non-O1 strain was found to have other 11 different nucleotides in ctxB compared with those of the O1 and O139 strains. Therefore, DNA sequencing is a useful method for obtaining more complete genetic information. The approach could be improved by applying it to other more polymorphic regions of bacterial genome to obtain better epidemiological information among infected cases.

Aircraft noise, hearing ability, and annoyance

The relationship between aircraft noise, loss of hearing, and annoyance was explored in a study in two schools located near an international airport in Taiwan. Sixth-grade students (N = 242) were recruited from two schools and were classified into high- and low-noise-exposure groups, based on environmental noise measurements. Personal-equivalent 24-h noise exposure was measured to determine noise exposure at the individual level, and it was compared with hearing threshold level and with aircraft noise measured at the environmental level. Individual hearing threshold levels did not differ between environmental high- and low-noise-exposure groups, as evidenced by the lack of difference between the two groups for noise exposure measured at the individual level. However, the proportion of students who were annoyed by aircraft noise was higher in the environmental high-noise-exposure group, although personal 24-h noise exposure was not a factor for annoyance. The results indicated that environmental noise measurement was not an appropriate criterion for assessment of auditory damage (or noise-induced hearing loss) in Taiwan. As well, aircraft-noise exposure in Taiwan did not appear to affect the hearing threshold but nonetheless annoyed schoolchildren near the airport.

Assessment of interlaboratory performance on the measurement of blood lead levels in Taiwanese adults

The purpose of this proficiency study was to assess the accuracy and consistency of blood lead level (BLLs) measurements in a study of Taiwanese adults. Three methods, including a certified blood accuracy test, an interlaboratory precision test and an intertime repeated measurement test, were applied to the six participating laboratories. Accuracy tests showed that most of the blood lead measurements were within the acceptable criteria proposed by United States Center for Disease Control and Prevention (U.S. CDC). However, an average of 11% underestimation was found at BLLs below 15 micrograms/dl. Coefficients of variation (CVs) were high in the first 3 months. After technical improvements, the CVs were reduced to acceptable limits of around 15% at low target lead values and 7% at high lead values. Interlaboratory variations of measurements in blood from ten normal healthy donors showed that the standard deviations were less than 2 micrograms/dl, which is within the acceptable criteria of +/- 4 micrograms/dl, in 8 out of 10 samples. Repeated measurements of BLLs in 54 blood samples over two months showed that most of the differences were within the acceptable range with a few exceptions. The mean BLLs measured in the baseline (pre-test) and two months later (post-test) were nearly identical. This proficiency test provides comparable and reliable results of BLL estimations in this multilaboratory study. However, the accuracy and consistency at low BLLs need to be improved.

Establishment of an occupational diseases surveillance system to monitor blood lead levels in Taiwan

BACKGROUND

Occupational diseases share many common characteristics with infectious diseases. However, the successful approach of using surveillance systems to eradicate infectious diseases has never been applied to the control and prevention of occupational diseases.

METHODS

On the basis of a nationwide survey of blood lead levels in the general population in Taiwan, we (the Ministry of Health, Taiwan) have developed an obligatory surveillance system for blood lead.

RESULTS

This government-administered system, which uses laboratory data as its source of information, enrolls all workers whose blood lead level exceeds regulation points (40 microgram/dl for men and 30 micrograms/dl for women). A Group of Health Promotion of Lead-using Workers (GHPLW) has been organized to be responsible for conducting epidemiological investigations to locate exposure sources in the workplace and to improve the working environment of cases and other workers with the same exposure.

CONCLUSIONS

We emphasize that the accomplishment of the GHPLW's task depends not only on "curing" the case, but also on eradicating the lead exposure source and decreasing the blood lead level of workers in the workplace during long-term follow-up. The system aims to upgrade occupational disease control to the stage of specific prevention and health promotion. The establishment of this system is a historic step in industrial hygiene and occupational disease prevention in Taiwan.

Blood lead levels in the general population of Taiwan, Republic of China

The purpose of this study was to investigate the environmental lead exposure of the general population in Taiwan. A total of 2919 residents of Taiwan were selected by multistage sampling methods. The participants were characterized by questionnaires and 10 ml venous blood was collected for blood lead measurement. A quality assurance/quality control program was designed during the analysis of blood lead levels. The mean blood lead level of 2719 residents without occupational lead exposure was 8.29 +/- 5.92 micrograms/dl. After adjustment for age and sex distribution to the Taiwan general population, the mean blood lead level was 8.10 micrograms/dl. Adjusted for an 11% underestimation of blood lead levels among the six laboratories, the mean blood lead level was estimated to be 8.99 micrograms/dl. This study also found that blood lead levels were associated with personal characteristics, i.e., gender, ethnic group, education level; lifestyle factors, i.e., smoking, alcohol consumption, sources of drinking water; and residential location, i.e., levels of urbanization, distance of house from the road. However, age, floor of residence, milk consumption, betel nut consumption, and Chinese herbal drug consumption were not found to be associated with blood lead levels. These results show that blood lead levels in Taiwan residents were not higher than in most developed and developing countries. Environmental lead pollution does not seem to be a serious problem in Taiwan.

Comparison of blood pressure in deaf-mute children and children with normal hearing: association between noise and blood pressure

The present study assessed the relationship between noise exposure and blood pressure. The study population consisted of 892 children from two elementary schools. The noise-sensitive group comprised 583 subjects with normal hearing from one school, while the noise-insensitive group comprised 309 deaf-mutes from another school. The deaf subjects had significantly lower blood pressure than the subjects with normal hearing (P < 0.05) after adjustment for age. Multiple regression analysis revealed that body mass index, age, and hearing ability explained a significant amount of the variation in systolic and diastolic blood pressure (R2 = 0.17 and 0.16, respectively). On the basis of the results, it is suggested that noise exposure is associated with higher systolic and diastolic blood pressure.

Prevalence of shoulder and upper-limb disorders among workers in the fish-processing industry

A cross-sectional study was conducted among fish-processing workers to evaluate the prevalence of shoulder and upper-limb discomforts and to assess the associated ergonomic risk factors. A prestructured interview, a medical check-up, and job analyses were performed to determine musculoskeletal disorders among 207 workers in eight factories. The results showed shoulder girdle pain (30.9%), epicondylitis (14.5%), and carpal tunnel syndrome (15.0%) as the three most common soft-tissue disorders. The odds ratio of shoulder girdle pain was 1.6 (95% CI 1.1-2.5) among the workers who performed tasks with repetitive movement of their upper limbs, while it was 1.8 (95% CI 1.2-2.5) for the workers who sustained forceful movement of their upper limbs during work. Women taking oral contraceptives had a 2.0 times higher odds ratio for carpal tunnel syndrome than did other women. It would appear that untrained or unskilled workers were prone to suffer from musculoskeletal disorders.