bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased morbidity odds ratio of primary liver cancer and cirrhosis of the liver among vinyl chloride monomer workers.
Authors: Du C L , Wang J D
Published: January 2009

OBJECTIVES: To determine if there is an increased risk of admission to hospital for various diseases among vinyl chloride monomer (VCM) workers. METHODS: 2224 workers with occupational exposure to VCM were identified for occurrence of disease based on a search of hospital computer files on labour insurance. These data were compared with those of workers manufacturing optical equipment and motorcycles from 1 January 1985 to 31 March 1994. Cardiovascular and cerebrovascular diseases were used as reference diseases, and the age adjusted morbidity odds ratio (MOR) was calculated. RESULTS: A significantly increased risk of admission to hospital among VCM workers due to primary liver cancer (MOR 4.5-6.5), cirrhosis of the liver (MOR 1.7-2.1), and other chronic diseases (MOR 1.5-2.0) was found. There were eight cases of primary liver cancer, all with heavy previous exposure to VCM. Another four cases of hepatoma in polyvinyl chloride (PVC) workers were found in the death registry. Ten out of 11 cases of hepatoma, with detailed medical information, were carriers of hepatitis B virus. The average latent period (20 years) was not different from other studies. Alternative agents of primary liver cancer were largely ruled out, suggesting that the combination of hepatitis B and VCM may lead to primary liver cancer. CONCLUSION: There is an increased risk of primary liver cancer in workers exposed to VCM, although the incomplete coverage of the Labor Insurance Bureau data warrants cautious interpretation of the results. Further study exploring the synergistic effects of VCM and hepatitis B is also indicated.
Association between hospital emergency visits for asthma and air pollution in Valencia, Spain.
Authors: Tenías J M , Ballester F , Rivera M L
Published: January 2009

OBJECTIVE: To assess the short term effect of concentrations of black smoke, sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) in ambient air on emergency room visits for asthma in the city of Valencia, Spain during the period 1994-5. METHODS: Ecological study with time series data and application of Poisson regression. Associations between number of daily emergency visits in a city's hospital and concentrations of air pollutants were analysed taking into account potential confounding factors by the standardised protocol of the air pollution and health: a European approach (APHEA) project. RESULTS: Mean (range) daily number of emergency room visits for asthma was 1 (0-5). Concentrations of all pollutants studied remained within current air quality standards. The association between an increase of 10 micrograms/m3 in ambient air pollution and asthma, measured as a relative risk (RR) of emergency visits, was significant for NO2 24 hour mean (lag 0, RR 1.076, 95% confidence interval (95% CI) 1.020 to 1.134), NO2 hour maximum (lag 0, RR 1.037, 95% CI 1.008 to 1.066), and O3 hour maximum (lag 1, RR 1.063, CI 95% 1.014 to 1.114). The association was not significant for SO2 or for black smoke during the period analysed. The effects were not significantly different for the time of year, cold months (November to April), or warm months (May to October). CONCLUSIONS: Current concentrations of ambient air pollution in Valencia are significantly associated with emergency room visits for asthma. This association is high and more consistent for NO2 and O3 than for particulate matter and SO2 (classic pollutants).
Job strain, social support at work, and incidence of myocardial infarction.
Authors: Hammar N , Alfredsson L , Johnson J V
Published: January 2009

OBJECTIVES: The combination of high psychological job demands and low decision latitude (high job strain) has been associated with an increased risk of coronary heart disease. It has been proposed that this may also be the case for low social support at work. The aim of this study was to analyse the relations between these psychosocial factors and incidence of myocardial infarction. METHODS: Associations between psychosocial work characteristics and incidence of myocardial infarction was investigated through a population based case-control study. The study base comprised employed men and women in five Swedish counties during the years 1976-84. Cases of first myocardial infarction were identified from hospital discharge registers and death records from outside hospital, controls were selected through a random sample, and psychosocial work environment was assessed through a job exposure matrix on the basis of the occupation in the 1970 and 1975 censuses. RESULTS: An increased incidence of myocardial infarction was found for men and women in occupations characterised by low decision latitude. For men this increase was seen primarily in combination with high psychological demands (high job strain) and low social support at work. Younger men (30-54 years of age) in occupations with both high job strain and low social support at work had a relative risk of 1.79 (95% confidence interval (95% CI) 1.22 to 2.65) compared with subjects in low strain and high social support jobs after controlling for age, county of residence, and socioeconomic group. CONCLUSIONS: Our results indicate that jobs characterised by low decision latitude, high job strain, or low social support at work may be associated with an increased risk of acute myocardial infarction. If these associations are causal they may be of substantial importance from the point of view of workers' health.
Risk of hepatitis A infection in sewage workers.
Authors: Brugha R , Heptonstall J , Farrington P , Andren S , Perry K , Parry J
Published: January 2009

OBJECTIVE: To evaluate the risk of hepatitis A virus (HAV) infection among sewage workers from occupational exposure to raw sewage. METHODS: An analytical cross sectional study of 241 company employees with possible occupational exposure to sewage in a large water and sewerage company was carried out. Previous exposure to hepatitis A virus infection was assessed, as were its associations with possible risk factors. RESULTS: Frequent occupational exposure to raw sewage was a significant risk factor for HAV infection, independently of other known risk factors (odds ratio 3.73, 95% confidence interval 1.48 to 9.37). Of 50 employees who reported occupational exposure to raw sewage most of the time, 30 (60%) had had HAV infection. CONCLUSION: Employees who are likely to be at risk of frequent exposure should have their immunity ensured. The salivary assay for IgG anti-HAV used in the study was highly specific and would be suitable for prevaccination testing of older employees, who are more likely to be immune.
Exposure to blood borne viruses and the hepatitis B vaccination status among healthcare workers in inner London.
Authors: Gyawali P , Rice P S , Tilzey A J
Published: January 2009

Occupational exposure to blood borne viruses was examined during one year at a London teaching hospital. A total of 236 incidents occurred of which 83% were related to sharps, 32% were clearly avoidable, and 7% involved an infected source patient. Overall uptake of hepatitis B vaccine was 78% but it was particularly low in paramedical (70%) and domestic staff (45%). Continued effort needs to be applied to improve uptake of hepatitis B vaccine and to maintain high standards of control of infection.
Chinese herbal medicine, sibship, and blood lead in children.
Authors: Cheng T J , Wong R H , Lin Y P , Hwang Y H , Horng J J , Wang J D
Published: January 2009

OBJECTIVES: Risk factors for increased blood lead concentration (BPb) has been investigated. However, the effect of sibship and Chinese herbal medicine on BPb has not been systematically studied. In this study BPb data from voluntary testing was used to determine if Chinese herbal medicine and sibship were associated with BPb. METHODS: 319 children aged 1-7 were tested for BPb. Meanwhile, parents were interviewed to obtain information including consumption of Chinese herbal medicine, living environment, lifestyle, and sibship of the children tested. RESULTS: The mean (SD) BPb of 319 preschool children was 4.4 (2.4) micrograms/dl. The consumption of Ba-baw-san (a Chinese herbal medicine) was significantly associated with increased BPb in children (p = 0.038). Further multivariate regression analysis of BPb in 50 pairs of siblings showed the factors of being brothers explained 75% of variation for BPb, and being sisters and brother-sister explained 51% and 41% of variation respectively. CONCLUSION: Chinese herbal medicine and children's play patterns within the family expressed in different types of sibship are the main determinants of low concentrations of BPb in preschool children of Taiwan.
Correlation between the prevalence of certain fungi and sick building syndrome.
Authors: Cooley J D , Wong W C , Jumper C A , Straus D C
Published: January 2009

OBJECTIVE: To examine the role of fungi in the production of sick building syndrome. METHODS: A 22 month study in the United States of 48 schools (in which there had been concerns about health and indoor air quality (IAQ). Building indoor air and surface samples, as well as outdoor air samples were taken at all sites to look for the presence of fungi or their viable propagules. RESULTS: Five fungal genera were consistently found in the outdoor air and comprised over 95% of the outdoor fungi. These genera were Cladosporium (81.5%), Penicillium (5.2%), Chrysosporium (4.9%), Alternaria (2.8%), and Aspergillus (1.1%). At 20 schools, there were significantly more colony forming units per cubic metre (CFU/m3) (p < 0.0001) of propagules of Penicillium species in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. At five schools, there were more, although not significant (p = 0.10), Penicillium propagules in the air samples from complaint areas when compared with the outdoor air samples and the indoor air samples from noncomplaint areas. In 11 schools, the indoor air (complaint areas) fungal ratios were similar to that in the outdoor air. In these 11 schools Stachybotrys atra was isolated from swab samples of visible growth under wetted carpets, on wetted walls, or behind vinyl wall coverings. In the remaining 11 schools, the fungal ratios and CFU/m3 of air were not significantly different in different areas. Many of the schools took remedial action that resulted in an indoor air fungal profile that was similar to that outdoors. CONCLUSIONS: Propagules of Penicillium and Stachybotrys species may be associated with sick building syndrome.
Cancer incidence in urban bus drivers and tramway employees: a retrospective cohort study.
Authors: Soll-Johanning H , Bach E , Olsen J H , Tüchsen F
Published: January 2009

OBJECTIVE: To investigate the risk of cancer associated with exposure to air pollution among bus drivers and tramway employees. METHODS: A retrospective cohort study of 18,174 bus drivers or tramway employees in Copenhagen in the period 1900-94. Data on employment were obtained from company files. Information on cancer was obtained from the Danish Cancer Registry. RESULTS: Findings showed that bus drivers or tramway employees had an increased risk of all malignant neoplasms (standardised incidence ratio (SIR) 1.24, 95% confidence interval (95% CI) 1.19 to 1.30). The relative risk was significantly increased for both men and women (SIR 1.24, 95% CI 1.19 to 1.30 and 1.28, 1.06 to 1.53, respectively). People employed for < 3 months had no increased risk of cancer (1.04, 0.81 to 1.31). For men who were employed for > 3 months the risk of lung cancer (1.6, 1.5 to 1.8), laryngeal cancer (1.4, 1.0 to 1.9), kidney cancer (1.6, 1.3 to 2.0), bladder cancer (1.4, 1.2 to 1.6), skin cancer (1.1, 1.0 to 1.2), pharyngeal cancer (1.9, 1.2 to 2.8), rectal cancer (1.2, 1.0 to 1.5) and liver cancer (1.6, 1.2 to 2.2) was significantly increased. For women employed for > 3 months the risk of lung cancer was significantly increased (2.6, 1.5 to 4.3). CONCLUSION: This cohort study shows that bus drivers and tramway employees are at an increased risk of developing several types of cancer. This might be due to the exposure to air pollution during working hours or to other risk factors, primarily smoking.
Air pollution and daily mortality in Rome, Italy.
Authors: Michelozzi P , Forastiere F , Fusco D , Perucci C A , Ostro B , Ancona C , Pallotti G
Published: January 2009

OBJECTIVES: To assess the relation between several daily indicators of air pollution (particulates and gases) and daily mortality in the metropolitan area of Rome and in the central part of the city. METHODS: Time series analysis. The associations between daily concentrations of pollutants (particles, SO2, NO2, CO, O3) recorded by five fixed monitors and daily total mortality in the period from January 1992 to June 1995 were evaluated. The analysis included examination of the pollution effect on mortality by place of residence within the metropolitan area, by season, age, place of death (in and out a hospital), and cause of death (cardiovascular and respiratory disease). The Poisson model included loses smooth functions of the day of study, mean temperature, mean humidity, and indicator variables for day of the week and holidays. RESULTS: The mean daily number of deaths was 56.9 (44.8 among people > or = 65 years old). A mean of 36.3 deaths occurred in the city centre; 37.3 deaths a day were recorded in a hospital. Total mortality was significantly associated with a 10 micrograms/m3 increase in particles (0.4%) on that day (log 0), and with a 10 micrograms/m3 increase in NO2 at lag 1 (0.3%) and lag 2 (0.4%) (1 and 2 days before, respectively). The effect of particles (lag 0) and of NO2 (lag 2) on total mortality was higher among those living in the city centre (0.7% and 0.5%, respectively). The risk estimates were higher in the warmer season (1.0% and 1.1%, respectively), whereas no difference was found for those dying in or out of the hospital. The effect of particles was robust to a sensitivity analysis and to the inclusion of NO2 in the regression model. CONCLUSIONS: Increase in particulates and NO2, generated by the same mobile combustion sources, is associated with a short term increase in mortality in Rome. The effect is more evident among residents in the city centre, where the levels of exposure to pollutants recorded by fixed monitors are probably more reliable indicators of personal exposure.
Small area study of mortality among people living near multiple sources of air pollution.
Authors: Michelozzi P , Fusco D , Forastiere F , Ancona C , Dell'Orco V , Perucci C A
Published: January 2009

OBJECTIVE: In the area of Malagrotta, a suburb of Rome (Italy), a large waste disposal site, a waste incinerator plant, and an oil refinery plant became operational in the early 1960s and have represented three major sources of air pollution. To evaluate the potential health risk due to airborne contamination around these point sources, a small area analysis of mortality was conducted. Cancer of the liver, larynx, lung, kidney, lymphatic, and haematopoietic systems were evaluated. METHODS: Sex and age specific mortality (1987-93) and population denominators (1991) were available for the census tracts of the metropolitan area of Rome. Standardised mortality ratios (SMRs) were computed separately for males and females in bands of increasing distance from the plants, up to a radius of 10 km. Stone's test for the decline in risk with distance was performed with increments in radius of 1 km; SMRs were also computed after adjusting for a four level index of socioeconomic status. RESULTS: No overall excess or decline in risk with distance was found for liver, lung, and lymphohaematopoietic cancers in either sex. For laryngeal cancer, an increased but not significant risk was found at 0-3 km and at 3-8 km. A significant decline with distance in mortality from laryngeal cancer was found among men (p = 0.03); the trend remained after adjusting for the socioeconomic index (p = 0.06). CONCLUSIONS: The study showed no association between proximity to the industrial sites and mortality for most of the several conditions considered. However, mortality from laryngeal cancer declined with distance from the sources of pollution. This result is interesting, as previous findings of an increased risk of laryngeal cancer near incinerators have been controversial.
Health survey of former workers in a Norwegian coke plant: Part. 1. Estimation of historical exposures.
Authors: Romundstad P R , Rønneberg A , Leira H L , Bye T
Published: January 2009

OBJECTIVE: To estimate historical exposure levels at a coke plant for all agents considered to be of importance for epidemiological studies of mortality and cancer incidence. METHODS: Time weighted average exposure (8 h TWA) was estimated based on personal measurements for polycyclic aromatic hydrocarbons (PAHs) and carbonaceous particulates. Exposure to quartz was estimated relative to the concentration of carbonaceous particulates. These estimates were adjusted for the use of airstream helmets. Exposure to other agents were estimated qualitatively (asbestos, benzene, and arsenic) or semi-quantitatively (carbon monoxide (CO) and heat) based on measurements and other indicators of exposure. RESULTS: Exposure to PAHs was highest for those who worked at the top of the ovens (300 micrograms/m3) in the period from 1970-6. The estimated PAH exposure was reduced to an average of 65 micrograms/m3 after the introduction of exposure control measures in 1976. The estimates for carbonaceous particulates ranged from 1 to 16 mg/m3, with the highest exposure for workers at the top of the ovens and at the coke screening station. CONCLUSIONS: The exposure of greatest concern in this study is to PAHs, but exposures to carbonaceous particulates and CO may also be of importance. The major limitations of this study are the lack of personal measurements before 1975 and the total lack of measurements for some of the exposed categories of workers. Despite these limitations, we think that this assessment reflects the actual exposures for most of the former employees. The assessment thus provides a reasonable tool for the subsequent epidemiological study and for future epidemiological follow up studies at the coke plant.
Occupational exposures to solvents and aluminium and estimated risk of Alzheimer's disease.
Authors: Graves A B , Rosner D , Echeverria D , Mortimer J A , Larson E B
Published: January 2009

OBJECTIVES: To study the role of occupational exposures to solvents and aluminium in the aetiology of Alzheimer's disease (AD). An industrial hygienist rated exposure. METHODS: 89 subjects diagnosed with probable AD were matched by age, sex, and type of informant to 89 controls. Subjects were identified from a large health maintenance organisation in Seattle, WA. A complete occupational history was obtained from spouses of cases and controls as well as from controls themselves. After the interview an industrial hygienist, blinded to case-control status, rated exposures. RESULTS: Non-significant associations were found between AD and ever having been occupationally exposed to solvents (odds ratio (OR) 1.77, 95% confidence interval (95% CI) 0.81 to 3.90) and aluminium (OR 1.46, 95% CI 0.62 to 3.42). Although an increasing risk was found with increasing number of years of exposure to solvents, there was an inverse association between exposure intensity and AD, and measures of cumulative exposure taking into account both intensity and duration of exposure were not significant. Analysis of the age at which half the cumulative exposure to solvents was achieved showed that an older age incurred a greater risk of AD than a younger age. However, the total amount of exposure carried no risk. CONCLUSIONS: The results suggest that lifetime occupational exposure to solvents and aluminium are not likely to be important risk factors for Alzheimer's disease.
Best estimate of the magnitude of mortality due to occupational exposure to hazardous substances.
Authors: Morrell S , Kerr C , Driscoll T , Taylor R , Salkeld G , Corbett S
Published: January 2009

OBJECTIVES: With a proportionate attributable risk approach, to estimate the magnitude of premature mortality induced by exposure to hazardous substances in the Australian workforce. METHODS: Estimates of the magnitude of mortality induced by exposure to hazardous substances in the Australian work-force were calculated by the proportionate attributable risk approach after careful consideration of options for methodological refinements. The main data sources used were unit mortality datasets (individual deidentified death records), and tabulations when these were unavailable. RESULTS: The estimated number of deaths that occurred in Australia each year from occupational exposure to hazardous substances was 2290; 78% of these were men. The rate of mortality attributable to occupational exposure to hazardous substances was three to four times greater in male workers than in female workers. Male (productive) person-years of life lost (PYLL) were generally eight times higher than female PYLL. Cancer was the prime cause of death, followed by renal, cardiovascular, neurological, and chronic respiratory disease. Acute toxic episodes accounted for a small proportion of mortality but yielded a much larger proportion of PYLL, reflecting the relatively young ages of those who experienced fatal effects. CONCLUSIONS: Although national estimates of the proportions of mortality attributable to occupational exposure to hazardous substances seemed to be validly derived, uncertainties remain associated with the lack of an empirical basis for derivation of proportionate risk fractions used in the calculations. The finding of an appreciable burden of mortality that is attributable to past occupational exposure to hazardous substances emphasises the necessity for occupational health and safety authorities to measure and reduce worksite exposures. There is also an incentive to encourage the construction of appropriately designed cohort studies across industries and occupational groupings so that, ultimately, risk estimates may be directly calculated and applied to total workforce data for the definitive estimation of the magnitude of harm induced by occupational exposure to hazardous substances.
Effects of experimental exposure to triethylamine on vision and the eye.
Authors: Järvinen P , Engström K , Riihimäki V , Ruusuvaara P , Setälä K
Published: January 2009

OBJECTIVES: To determine the effect of triethylamine (TEA) on the cornea and to evaluate the cause of blurred vision. To find the lowest observed effect concentration of exposure to TEA. METHODS: Four people were exposed to TEA for 4 hours at concentrations of 40.6, 6.5, and 3.0 mg/m3. Before and after every exposure, symptoms and ocular microscopy findings were recorded. Binocular visual acuity and contrast sensitivity at 2.5% contrast were also measured. Also, before and after the 40.6 mg/m3 exposure, corneal thickness was measured and ocular dimensions were recorded by ultrasonography, endothelial cells of the cornea were analysed, and serum and lacrimal specimens were collected for the analysis of TEA. RESULTS: After exposure to 40.6 mg/m3 TEA there was a marked oedema in the corneal epithelium and subepithelial microcysts. However, corneal thickness increased only minimally because of the epithelial oedema. The lacrimal concentrations of TEA were, on average (range) 41 (18-83) times higher than the serum TEA concentrations. The vision was blurred in all subjects and visual acuity and contrast sensitivity had decreased in three of the four subjects. After exposure to TEA at 6.5 mg/m3 two subjects experienced symptoms, and contrast sensitivity had decreased in three of the four subjects. There were no symptoms or decreases in contrast sensitivity after exposure to a TEA concentration of 3.0 mg/m3. CONCLUSIONS: TEA caused a marked oedema and microcysts in corneal epithelium but only minor increases in corneal thickness. The effects may be mediated by the lacrimal fluid owing to its high TEA concentration. Four hour exposure to a TEA concentration of 3.0 mg/m3 seemed to cause no effects, whereas exposure to 6.5 mg/m3 for the same period caused blurred vision and a decrease in contrast sensitivity.
Oral and dermal absorption of chlorpyrifos: a human volunteer study.
Authors: Griffin P , Mason H , Heywood K , Cocker J
Published: January 2009

OBJECTIVES: To determine the kinetics of elimination of urinary dialkylphosphate metabolites after oral and dermally applied doses of the organophosphate pesticide chlorpyrifos to human volunteers and to determine whether these doses affected plasma and erythrocyte cholinesterase activity. METHOD: Five volunteers ingested 1 mg (2852 nmol) of chlorpyrifos. Blood samples were taken over 24 hours and total void volumes of urine were collected over 100 hours. Four weeks later 28.59 mg (81567 nmol) of chlorpyrifos was administered dermally to each volunteer for 8 hours. Unabsorbed chlorpyrifos was washed from the skin and retained for subsequent measurement. The same blood and urine sampling regime was followed as for the oral administration. Plasma and erythrocyte cholinesterase concentrations were determined for each blood sample. The concentration of two urinary metabolites of chlorpyrifos--diethylphosphate and diethyl-thiophosphate--was determined for each urine sample. RESULTS: The apparent elimination half life of urinary dialkylphosphates after the oral dose was 15.5 hours and after the dermal dose it was 30 hours. Most of the oral dose (mean (range) 93% (55-115%)) and 1% of the applied dermal dose was recovered as urinary metabolites. About half (53%) of the dermal dose was recovered from the skin surface. The absorption rate through the skin, as measured by urinary metabolites was 456 ng/cm2/h. Blood plasma and erythrocyte cholinesterase activity did not fall significantly during either dosing regime. CONCLUSION: An oral dose of chlorpyrifos was readily absorbed through the skin and almost all of the dose was recovered as urinary dialkylphosphate metabolites. Excretion was delayed compared with the oral dose. Only a small proportion of the applied dose was recovered during the course of the experiment. The best time to collect urine samples for biological monitoring after dermal exposure is before the shift the next day. The amounts of chlorpyrifos used did not depress acetyl cholinesterase activity but could be readily detected as urinary dialkylphosphate metabolites indicating that the urinary assay is a more sensitive indicator of exposure.
Reappraisal of the relation between blood lead concentration and blood pressure among the general population in Taiwan.
Authors: Chu N F , Liou S H , Wu T N , Chang P Y
Published: January 2009

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.
Perceived job stress and mental health in precision machine workers of Japan: a 2 year cohort study.
Authors: Mino Y , Shigemi J , Tsuda T , Yasuda N , Bebbington P
Published: January 2009

OBJECTIVES: To determine whether perceived job stress affects mental health in occupational settings. METHODS: A 2 year cohort study was conducted. Initially, a survey including the general health questionnaire (GHQ) and a questionnaire about perceived job stress was carried out. Of 462 workers who initially showed a GHQ score of < or = 7,310 were successfully followed up for 2 years. The 2 year risks of developing mental ill health (a GHQ score > or = 8) were assessed relative to perceived job stress. To control for potential confounding factors, multiple logistic regression analyses were conducted. RESULTS: The overall 2 year risk for developing mental ill health was high at 57.7%. Workers who reported aspects of perceived job stress showed a greater 2 year risk than those without stress. Multiple logistic regression analyses showed that some components of perceived job stress were associated with a higher 2 year risk, among which "not allowed to make mistakes" showed the largest adjusted odds ratio (OR) (95% confidence interval (95% CI) of 2.37 (1.32 to 4.29). "Poor relationship with superior" had a significant effect on mental health only in women, with an adjusted OR (95% CI) of 3.79 (1.65 to 8.73). CONCLUSIONS: Certain specific items of perceived job stress seem to be associated with mental ill health in workers. These could broadly be described as job strain, or job demand items. The type of job stress that predicts mental health may be dependent on the characteristics of the workplace investigated.
Abnormal tear dynamics and symptoms of eyestrain in operators of visual display terminals.
Authors: Nakaishi H , Yamada Y
Published: January 2009

OBJECTIVES: To clarify the relation between the prevalence of dry eye syndrome and subjective symptoms of asthenopia in visual display terminal (VDT) operators. METHOD: 722 VDT workers (242 subject workers with symptoms of asthenopia and 480 controls without such symptoms) without obvious organic ocular diseases received an ophthalmological examination consisting of refractometry and a tear function (phenol red thread) test. RESULTS: More than 30% of symptomatic workers were found to meet the criteria of dry eye, and the odds ratio compared with the controls was 4.61 (p < 0.001). This odds ratio was significantly greater than that obtained for refractive errors (2.31). CONCLUSIONS: Although this cross sectional study could not prove that dry eyes are the cause of asthenopia, the profound association of dry eyes with symptoms of asthenopia could be verified. It would be useful to carry out tear function tests in workers with symptoms of asthenopia.
A relative power table for nested matched case-control studies.
Authors: Pang D
Published: January 2009

OBJECTIVE: To calculate relative powers for nested case-control studies for different values of both relative risk and numbers of controls per case, given a fixed number of cases available for analysis. METHODS: Algebraic and numerical methods. RESULTS: In nested case-control studies, statistical power is a function of relative risk, rarity of exposure, number of case-control sets, and the number of controls per case. CONCLUSION: The dictum that sufficient power will be obtained in a nested case-control study by selecting only four controls per case cannot be sustained. Appropriate numbers need to be calculated for specific studies.
Analysis of a petrol plume over England: 18-19 January 1997.
Authors: Welch F , Murray V S , Robins A G , Derwent R G , Ryall D B , Williams M L , Elliott A J
Published: January 2009

OBJECTIVES: About 7000 tonnes of unleaded petrol were discharged into the English Channel after a tanker collision off Ostend on Saturday 18 January 1997. The petrol evaporated and the vapour plume was carried across the central part of England to Wales, resulting in reports of unidentified odours, and irritation of the eyes, skin, and upper respiratory tract. This work uses this incident to show how marine and atmospheric dispersion modelling together with routine air quality monitoring can assist in identifying hazards to the population at risk from chemical incidents. METHODS: Public health surveillance and results from environmental sampling were compared with the behaviour of the plume as predicted by computer modelling. RESULTS: The predicted plume path and dispersion were shown to correlate well with the results from surveillance and environmental analysis. CONCLUSIONS: There is a need for public health professionals to interact with medical toxicologists, atmospheric and marine scientists and engineers, and other environmental experts in managing events of this nature.
Reproductive endocrine effects of acute exposure to toluene in men and women.
Authors: Luderer U , Morgan M S , Brodkin C A , Kalman D A , Faustman E M
Published: January 2009

OBJECTIVES: Despite observation of adverse reproductive effects of toluene, including alterations of serum gonadotropins (luteinising hormone (LH) and follicle stimulating hormone (FSH)) in humans, little is known of the mechanism of toxicity. The hypothesis was tested that toluene acutely suppresses pulsatile gonadotropin secretion by measuring LH and FSH at frequent intervals during controlled exposure to toluene. METHODS: Women in the follicular and luteal phases of the menstrual cycle and men were randomised to inhale filtered air with or without 50 ppm toluene through a mouthpiece for 3 hours (19% of the OSHA permissible exposure limit). Blood was sampled by intravenous catheter at 20 minute intervals for 3 hours before, 3 hours during, and 3 hours after exposure. Plasma LH, FSH, and testosterone were measured. Pulse amplitude, pulse frequency, and mean concentrations of LH and FSH for each of the 3 hour periods before, during and after exposure to toluene versus sham exposure were calculated with the ULTRA pulse detection program and compared by analysis of variance (ANOVA) with repeated measures. RESULTS: In men mean concentrations of LH showed a significant interaction (p < 0.05) between exposure and sampling period, with a greater LH decline during exposure to toluene than sham exposure. However, there was no concomitant effect on testosterone concentrations. The LH pulse frequency of women in the luteal phase showed a trend towards a significant interaction between exposure and sampling period (p = 0.06), with a greater decline in pulse frequency during exposure to toluene than sham exposure. There were no other significant effects of exposure to toluene. CONCLUSIONS: Three hour exposure to 50 ppm toluene did not result in abnormal episodic LH or FSH secretion profiles, however, subtle effects on LH secretion in men and women in the luteal phase were found. The clinical relevance of these effects is unclear, indicating the need for further study of reproductive function in exposed workers.
Mortalities of workers at the Nitro plant with exposure to 2-mercaptobenzothialzole.
Authors: Collins J J , Strauss M E , Riordan S G
Published: January 2009

OBJECTIVES: An update of a study of workers exposed to 2-mercaptobenzothiazole (MBT) at a rubber chemicals plant in Nitro, West Virginia is reported. The earlier study found high rates of lung cancer, prostate cancer, and bladder cancer in these workers who also had potential exposure to 4-aminobiphenyl (PAB), a potent bladder carcinogen. METHODS: This cohort mortality study examines the mortalities of 1059 full time white male production workers employed at the plant from 1955 to 1977. A detailed exposure assessment was done on the 600 workers with exposure to MBT. Nine years of additional follow up to the previous study are added. RESULTS: It was found that MBT workers have expected rates of lung (standardised mortality ratio (SMR) = 1.0 95% confidence interval (95% CI) 0.7 to 1.5) and prostate (SMR = 0.9, 95% CI 0.2 to 2.3) cancer. There was an excess of bladder cancer among MBT workers who had definite exposure to PAB (SMR = 27.1, 95% CI 11.7 to 53.4), and MBT workers with potential exposure to PAB (SMR = 4.3, 95% CI 1.4 to 10.0). However, there were no deaths from bladder cancer among workers with no exposure to PAB (SMR = 0.0, 95% CI 0.0 to 24.7), although there were only 0.2 deaths expected. CONCLUSIONS: The potential confounding of exposure to an unknown portion of PAB in the MBT workers makes it impossible to evaluate risk of bladder cancer in this population at this time. However, exposure to MBT does not seem to increase the risk of most cancers including cancers of the lung and prostate.
Correlation between urinary 2-methoxy acetic acid and exposure of 2-methoxy ethanol.
Authors: Shih T S , Liou S H , Chen C Y , Chou J S
Published: January 2009

OBJECTIVES: To examine the correlation between airborne 2-methoxy ethanol (ME) exposures and the urinary 2-methoxy acetic acid (MAA) and to recommend a biological exposure index (BEI) for ME. METHODS: 8 Hour time weighted average (TWA) personal breathing zone samples and urine samples before and after the shift were collected from Monday to Saturday for 27 workers exposed to ME and on Friday for 30 control workers. RESULTS: No correlation was found between airborne exposure to ME and urinary MAA for nine special operation workers due to the use of personal protective equipment. For 18 regular operation workers, a significant correlation (r = 0.702, p = 0.001) was found between urinary MAA (mg/g creatinine) on Friday at the end of the shift and the weekly mean exposures of ME in a 5 day working week. The proposed BEI, which corresponds to exposure for 5 days and 8 hours a day to 5 ppm, extrapolated from the regression equation is 40 mg MAA/g creatinine. A significant correlation was also found between the weekly increase of urinary MAA (Friday after the shift minus Monday before the shift) and the weekly mean exposures of ME (r = 0.741). The recommended value of the weekly increase of urinary MAA for 5 days repeated exposures of 5 ppm ME is 20 mg/g creatinine. No urinary MAA was detected in workers in the non-exposed control group. CONCLUSIONS: The Friday urinary MAA after the shift or the weekly increase of urinary MAA is a specific and a good biomarker of weekly exposure to ME.
Air pollution and hospital admissions for respiratory and cardiovascular diseases in Hong Kong.
Authors: Wong T W , Lau T S , Yu T S , Neller A , Wong S L , Tam W , Pang S W
Published: January 2009

OBJECTIVE: To investigate short term effects of concentrations of pollutants in ambient air on hospital admissions for cardiovascular and respiratory diseases in Hong Kong. METHODS: Retrospective ecological study. A Poisson regression was performed of concentrations of daily air pollutant on daily counts of emergency hospital admissions in 12 major hospitals. The effects of time trend, season, and other cyclical factors, temperature, and humidity were accounted for. Autocorrelation and overdispersion were corrected. Daily concentrations of nitrogen dioxide (NO2), sulphur dioxide (SO2), ozone (O3), and particulate matter < 10 microns in aerodynamic diameter (PM10) were obtained from seven air monitoring stations in Hong Kong in 1994 and 1995. Relative risks (RR) of respiratory and cardiovascular disease admissions (for an increase of 10 micrograms/m3 in concentration of air pollutant) were calculated. RESULTS: Significant associations were found between hospital admissions for all respiratory diseases, all cardiovascular diseases, chronic obstructive pulmonary diseases, and heart failure and the concentrations of all four pollutants. Admissions for asthma, pneumonia, and influenza were significantly associated with NO2, O3, and PM10. Relative risk (RR) for admissions for respiratory disease for the four pollutants ranged from 1.013 (for SO2) to 1.022 (for O3), and for admissions for cardiovascular disease, from 1.006 (for PM10) to 1.016 (for SO2). Those aged > or = 65 years were at higher risk. Significant positive interactions were detected between NO2, O3, and PM10, and between O3 and winter months. CONCLUSIONS: Adverse health effects are evident at current ambient concentrations of air pollutants. Further reduction in air pollution is necessary to protect the health of the community, especially that of the high risk group.
Clearance of man made mineral fibres from the lungs of sheep.
Authors: Dufresne A , Perrault G , Yamato H , Massé S , Bégin R
Published: January 2009

OBJECTIVES: To compare the clearance rate, the related pathology, and the chemical and morphological changes of three man made mineral fibres (MMMFs) in the sheep model of pneumoconiosis. METHODS: Fibrous particles were extracted from lung parenchyma and analysed by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). RESULTS: The concentration of MMMF11, MMMF21, refractory ceramic fibre (RCF-1), and crocidolite asbestos fibres decreased with time according to a slow and a fast kinetic component. There was a statistical difference in the four regression lines as a function of time and the type of fibres (p < 0.001). The diameter of MMMFs decreased during the course of the time, whereas the crocidolite fibres did not seem to show any change. There was a statistical difference in the four regression lines as a function of time (p = 0.037) and type of fibres (p < 0.001). Ferruginous bodies were counted in the 40 sheep for which the latency period was 2 years. No typical ferruginous bodies were found in the groups exposed to MMMFs. The geometric mean concentration of asbestos bodies in the group exposed to crocidolite was 2421 bodies/g lung tissue (95% CI 385 to 15260). CONCLUSIONS: The number of initially retained fibres decreased with time according to a slow and a fast kinetic component. MMMF11 and MMMF21 have similar clearance, faster than RCF-1 and crocidolite. The geometric mean diameter and length of MMMF decreased with time, but crocidolite did not. After 2 years in the sheep tracheal lobe, ferruginous bodies were not found in all three MMMF groups but were substantial in the crocidolite group. Clearance is thought to proceed through dissolution and macrophage translocation.
Analysis by sex of low back pain among workers from small companies in the Paris area: severity and occupational consequences.
Authors: Alcouffe J , Manillier P , Brehier M , Fabin C , Faupin F
Published: January 2009

OBJECTIVES: To describe workers with low back symptoms, to identify risk factors and to assess the occupational consequences separately in men and women. METHODS: A descriptive study was conducted between 1 October 1996 and 31 December 1996 in a sample of workers selected at random from all types of small companies in the Paris area. A group of 202 occupational physicians interviewed 7129 workers with a standardised questionnaire including the Nordic questionnaire. Data analysis was performed by sex in the two groups: with low back pain and without low back pain over the previous 12 months. The group with low back pain was then divided into four subgroups: mild cases (without referred pain), moderate cases (with referred pain above the knee), serious cases (with referred pain below the knee), and low back pain with occupational consequences. RESULTS: 7010 questionnaires were able to be evaluated. The sample consisted of 54.8% of men (3842) and 45.2% of women (3168), with a mean age of 37.8 and 37.0 years, respectively (p < 0.05). The following risk factors occurred significantly more often in men: high weight, height, body mass index (BMI), smoking, number of children, increased driving time and work time, material handling tasks, uncomfortable working positions. Most women were clerks (53%). Non-conditional logistic regression applied to the whole sample identified female sex as a risk factor (odds ratio (OR) = 1.85, 95% confidence interval (95% CI) 1.58 to 2.13). The following risk factors were common to both sexes: lifting weights > 10 kg, in women (OR 1.69, 95% CI 1.27 to 2.25) and in men (OR 1.27, 95% CI 1.06 to 1.53), uncomfortable working positions (OR 2.04, 95% CI 1.58 to 2.17 and OR 1.85, 95% CI 1.69 to 2.43), and absence of means to achieve good quality work (OR 1.39, 95% CI 1.19 to 1.63 and OR 1.38, 95% CI 1.15 to 1.65), respectively. Driving was a risk factor only in men and its importance increased with driving time (driving > 4 hours a day (OR 1.61, 95% CI 1.24 to 2.09)). Severe low back pain was linked to female sex (10.2% of women v 6.6% of men), high BMI, aging, and uncomfortable working positions. Low back pain with occupational consequences (n = 258) was not linked to sex, but only to aging and severity. CONCLUSIONS: The incidence and severity of low back pain were higher in women, although they seemed to be less exposed to known occupational risk factors. However, our results indicate a preponderance of these risk factors among female workers. Particular attention must therefore be paid to lifting of weights and uncomfortable working positions in female jobs (clerk, trading, health care staff).
Analysis of sickness absence among employees of four NHS trusts.
Authors: Ritchie K A , Macdonald E B , Gilmour W H , Murray K J
Published: January 2009

OBJECTIVES: To determine the value of using routinely collected sickness absence data as part of a health needs assessment of healthcare workers. METHOD: Sickness absence records of almost 12900 NHS staff for one calendar year were analysed. Three measures of absence, the absence rate, the absence frequency rate, and the mean duration of absence, were assessed for the population and comparisons made between men and women, full and part time and different occupational groups of staff. Also, the main causes of sickness absence were found. RESULTS: Almost 60% of the study population had no spells of sickness absence in the year of study and almost 20% had only one spell of sickness absence. Female staff were more likely to have experienced sickness absence than male staff. Although absence due to conditions related to pregnancy were included in the analysis, the incidence of these was not sufficient to account for the higher rates of absence among female staff. In general, full time staff had greater rates of sickness absence than part time staff. 71% of all absences were of < 1 week duration. The main known causes of sickness absence were respiratory disorders, digestive disorders, and musculoskeletal disorders. CONCLUSIONS: The transition from units managed directly from the health board to trusts with individual responsibility for personnel issues at the time of data collection resulted in variations in the quality of data available for analysis. This together with the use of "dump" codes has influenced the quality of the analysis. However, such data should be available for analysis to tailor occupational health care to the needs of the population.