bluuebunny/crossref_metadata_2025 huggingface dataset:
People can detect poor air quality well below guideline concentrations: a prevalence study of annoyance reactions and air pollution from traffic.
Authors: Forsberg B , Stjernberg N , Wall S
Published: December 2008

OBJECTIVES: Motor vehicle exhaust fumes are the main source of atmospheric pollution in cities in industrialised countries. They cause respiratory disease and annoy people exposed to them. The relation between ambient exposure to air pollution mainly from motor vehicles and annoyance reactions in a general population was assessed. Also, the importance of factors such as age, sex, respiratory disease, access to the use of a car, and smoking habits on the reporting of these reactions was studied. METHODS: A postal questionnaire was sent out in 55 urban areas in Sweden that had nearly identical air quality monitoring stations of the urban air monitoring network. From each area, 150 people aged 16-70 were randomly selected. The questionnaire contained questions on perception of air quality as well as a question on how often exhaust fumes were annoying. RESULTS: Six-monthly nitrogen dioxide concentrations correlated consistently with the prevalence of reported annoyance related to air pollution and traffic exhaust fumes. Black smoke and sulphur dioxide had no significant effects. The frequency of reporting annoyance reactions was higher among people with asthma, women, and people with lack of access to a car. CONCLUSIONS: In this study town dwellers could detect poor air quality at concentrations well below current guidelines for outdoor air pollution. This suggests that questionnaire studies have a place in monitoring air quality.
Prevalence of the sick building syndrome symptoms in office workers before and six months and three years after being exposed to a building with an improved ventilation system.
Authors: Bourbeau J , Brisson C , Allaire S
Published: December 2008

OBJECTIVE: The prevalence of symptoms associated with the sick building syndrome (SBS) has recently been shown to decrease by 40% to 50% among office workers six months after they were exposed to a building with an improved ventilation system. The objective of the present study was to find whether the decrease in the prevalence of symptoms was maintained three years later. METHODS: Workers from the same organisation occupied five buildings in 1991 and moved during that year to a single building with an improved ventilation system. All buildings had sealed windows with mechanical ventilation, air conditioning, and humidification. Workers completed a self administered questionnaire during normal working hours in February 1991 before moving, in February 1992 six months after moving, and in February 1995, three years after moving. The questionnaire encompassed symptoms of the eyes, nose and throat, respiratory system, skin, fatigue, and headache, as well as difficulty concentrating, personal, psychosocial, and workstation factors. During normal office hours of the same weeks, environmental variables were measured. RESULTS: The study population comprised 1390 workers in 1991, 1371 in 1993, and 1359 in 1995, which represents 80% of the population eligible each year. The prevalence of most symptoms decreased by 40% to 50% in 1992 compared with 1991. This was similar in 1995. These findings were significant and remained generally similar after controlling for personal, psychosocial, and work related factors. CONCLUSION: In this study, the decrease of 40% to 50% in the prevalence of most symptoms investigated six months after workers were exposed to a new building with an improved ventilation system was maintained three years later. The results of the present follow up study provide further support for a real effect of exposure to a new building with an improved ventilation system on the prevalence of symptoms associated with the SBS.
Assessment of occupational exposure in a population based case-control study: comparing postal questionnaires with personal interviews.
Authors: Blatter B M , Roeleveld N , Zielhuis G A , Verbeek A L
Published: December 2008

BACKGROUND: In case-control studies, data collection on occupational exposures by means of personal interviews is usually costly and time consuming. As detailed semiquantitative information on exposure from these interviews often has to be dichotomised in the analyses due to the small numbers of exposed subjects, the question is raised whether simple postal questionnaires yield the same results for occupational exposure in epidemiological studies as job specific personal interviews. METHODS: Data on occupational exposures during pregnancy were compared from 121 women who both completed a checklist with 17 occupational exposure categories in a postal questionnaire and were personally interviewed with specific questions on exposure with details of job and task. kappa Coefficients were calculated as measures of agreement corrected for chance, and sensitivity and positive predictive values as measures of validity and usefulness, with the exposure assessment based on information from the interview as the gold standard. RESULTS: Values of kappa varied from 0.09 for domestic cleaning agents to 0.70 for pesticides, indicating only low to moderate agreement between the questionnaire and the interview. Sensitivity ranged from 38% to 100%, with the highest values for agents used by healthcare workers. Positive predictive values were lower, between 9% and 63%, which indicates that overreporting was more common than underreporting in the questionnaire. CONCLUSIONS: These results underline the high potential for misclassification of occupational exposure in studies based on questionnaires. Therefore, postal questionnaires are not considered an alternative to job and task specific personal interviews in epidemiological studies.
Hepatitis A among workers from a waste water treatment plant during a small community outbreak.
Authors: De Serres G , Laliberté D
Published: December 2008

OBJECTIVE: This is a case report describing the occurrence of hepatitis A in three workers at a waste water treatment plant during a small community outbreak involving 16 cases. CASE REPORT: The first case was a 26 year old operator who had worked in the plant for two years, the second was a 23 year old employee hired to add new biolite in the secondary treatment area. These two cases never worked together and only met two or three times before the onset of disease in the second case. The third case occurred three months later in a 34 year old ventilation mechanic. All three cases were confirmed by IgM serology and virus was recovered by polymerase chain reaction in the stools of the last two cases. Despite an extensive search for other risk factors for hepatitis A in these workers none was found. CONCLUSION: This report confirms that hepatitis A is an occupational hazard for sewage workers. The numerous potential sources of contamination associated with that occupation support the use of vaccine to provide effective prevention.
Occupational exposure to magnetic fields in relation to mortality from brain cancer among electricity generation and transmission workers.
Authors: Harrington J M , McBride D I , Sorahan T , Paddle G M , van Tongeren M
Published: December 2008

OBJECTIVE: To investigate whether the risks of mortality from brain cancer are related to occupational exposure to magnetic fields. METHODS: A total of 112 cases of primary brain cancer (1972-91) were identified from a cohort of 84,018 male and female employees of the (then) Central Electricity Generating Board and its privatised successor companies. Individual cumulative occupational exposures to magnetic fields were estimated by linking available computerised job history data with magnetic field measurements collected over 675 person-workshifts. Estimated exposure histories of the case workers were compared with those of 654 control workers drawn from the cohort (nested case-control study), by means of conditional logistic regression. RESULTS: For exposure assessments based on arithmetic means, the risk of mortality from brain cancer for subjects with an estimated cumulative exposure to magnetic fields of 5.4-13.4 microT.y v subjects with lower exposures (0.0-5.3 microT.y) was 1.04 (95% confidence interval (95% CI) 0.60 to 1.80). The corresponding relative risk in subjects with higher exposures (> or = 13.5 microT.y) was 0.95 (95% CI 0.54 to 1.69). There was no indication of a positive trend for cumulative exposure and risk of mortality from brain cancer either when the analysis used exposure assessments based on geometric means or when the analysis was restricted to exposures received within five years of the case diagnosis (or corresponding period for controls). CONCLUSIONS: Although the exposure categorisation was based solely on recent observations, the study findings do not support the hypothesis that the risk of brain cancer is associated with occupational exposure to magnetic fields.
Sarin poisoning of a rescue team in the Matsumoto sarin incident in Japan.
Authors: Nakajima T , Sato S , Morita H , Yanagisawa N
Published: December 2008

OBJECTIVES: A nerve agent sarin (isopropyl methyl phosphonofluoridate) was released in Matsumoto city, Japan, on 27 June 1994. About 600 people were affected by the sarin, including seven who died. Fifty two rescuers engaged in helping the victims and 18 were affected. The aim was to investigate how the rescuers were affected by sarin. METHODS: Health examinations and a questionnaire survey were conducted with all rescuers. RESULTS: A rescuer who was one of the first engaged and who worked for about five hours in areas contaminated with sarin was admitted to hospital after poisoning; the others did not consult doctors although they showed slight muscarinic symptoms. The later the rescuers started their work, the less likely they were to experience symptoms of sarin exposure, and no one starting work 270 minutes after the original release of sarin was affected. The symptoms of exposure included ocular pain, darkness of visual field, nausea, vomiting, headache, rhinorrhea, narrowing of visual field, sore throat, fatigue, and dyspnoea, which were similar to those reported by the citizens who were sarin victims. There were no rescuers who had abnormal physical or neurological signs associated with sarin at the time of the physical examination conducted three weeks after the sarin release. A year after the sarin incident, the symptoms of all the rescuers had resolved. CONCLUSIONS: Rescuers should protect themselves with appropriate clothing, gloves, and a mask to prevent a secondary disaster for at least 24 hours after a similar accident.
Mortality of workers exposed to dieldrin and aldrin: a retrospective cohort study.
Authors: de Jong G , Swaen G M , Slangen J J
Published: December 2008

OBJECTIVE: To investigate the occurrence of long term health effects in humans exposed to aldrin and dieldrin, with an update of an earlier retrospective cohort mortality study. METHODS: A group of 570 workers employed between 1 January 1954 and 1 January 1970 either in a production or formulation plant were followed up for mortality until 1 January 1993. There were extensive industrial hygiene data available and biological monitoring data of aldrin and dieldrin for most of the workers. From these data individual estimates were made of the total intake of dieldrin. A total number of 2539.37 person-years at risk was added to the original study. RESULTS: 118 deaths were observed compared with 156 expected. No increase in mortality from liver cancer was found. However, there was an excess in mortality from rectal cancer. This excess was inversely related to the dose gradient. An analysis by job title did not show any excess cancer in any particular job. CONCLUSION: The study does not support a carcinogenic effect of dieldrin and aldrin in humans.
Mortality of Dutch coal miners in relation to pneumoconiosis, chronic obstructive pulmonary disease, and lung function.
Authors: Meijers J M , Swaen G M , Slangen J J
Published: December 2008

OBJECTIVES: To analyse the mortality patterns of former Dutch coal miners, focusing on coal workers' pneumoconiosis (CWP) and chronic obstructive pulmonary diseases (COPD) in relation to pre-existing impairment of lung function. METHODS: 3790 selected miners, medically examined between 1952 and 1963, were followed up to the end of 1991 with the municipal population registries and the causes of death from the death certificates were ascertained and converted to the codes from the ninth revision of the international classification of diseases (ICD-9). Mortality comparisons were made with the male population in The Netherlands, resulting in standardised mortality ratios (SMRs). 3367 miners had radiological manifestation of CWP at medical examinations. RESULTS: 80% of the miners died during the follow up period. Excess mortalities from CWP (SMR 4523) and COPD (SMR 179) were found. Coal miners without CWP also showed an increased mortality from COPD (SMR 2913). A diminished lung function (forced expiratory volume in one second (FEV1), or FEV1/FVC (forced vital capacity) ratio) at medical examination resulted in a significantly increased SMR for COPD (322 and 212 respectively) whereas normal lung function yielded expected mortalities from COPD. A positive correlation also emerged between diminished lung function and the SMR due to CWP. The body mass index (BMI) at the moment of medical examination was correlated with the risk of dying of COPD and CWP: a decreasing BMI resulting in an increased SMR. CONCLUSIONS: Not only infectious diseases and CWP but also COPD is an important cause of occupational mortality in miners with extensive exposure to coal mine dust. No obvious connection between pre-existing CWP and the COPD mortality exists. Impaired FEV1 and FEV1/FVC ratios are predictors of an increased risk of COPD death. The BMI seems to indicate the severity of the COPD, resulting in premature death.
Efficiency of different grouping schemes for dust exposure in the European carbon black respiratory morbidity study.
Authors: van Tongeren M , Gardiner K , Calvert I , Kromhout H , Harrington J M
Published: December 2008

OBJECTIVES: The aim of this study was to assess the theoretical efficiencies of different grouping strategies and its effect on the exposure-response relation in a study of respiratory morbidity associated with exposure to total inhalable and respirable carbon black dust. METHODS: A large epidemiological study is being undertaken to investigate the respiratory health of employees in the European carbon black manufacturing industry in relation to exposure to carbon black dust. In phase 2 of the study, repeated measurements of total inhalable and respirable dust were taken which enabled estimation of various components of variability in the exposure data (within and between worker variance and within and between group variance). These variance components were used to calculate the contrast in exposure between the groups in various classification schemes and to calculate the theoretical attenuation of the exposure-response relation and the standard error (SE) of the slope. RESULTS: High contrast in exposure was found when workers were classified according to the combination of their factory and job category as well as when these combinations were amalgamated into five exposure groups. Attenuation was minimal with most grouping schemes; only with the individual based strategy was the attenuation large. The SE of the theoretically attenuated exposure-response slope was smallest for the strategy based on individual people followed by the classification scheme based on factory and job category. CONCLUSIONS: It was concluded that, although some assumptions for the calculations of the attenuation of the exposure-response slope were not met, the most appropriate classification scheme of the worker seems to be by the combination of factory and job category.
Cancer mortality among electric utility workers exposed to polychlorinated biphenyls.
Authors: Loomis D , Browning S R , Schenck A P , Gregory E , Savitz D A
Published: December 2008

OBJECTIVES: To assess whether excess mortality from cancer, malignant melanoma of the skin, and cancers of the brain and liver in particular, is associated with long term occupational exposure to polychlorinated biphenyls (PCBs). METHODS: An epidemiological study of mortality was conducted among 138,905 men employed for at least six months between 1950 and 1986 at five electrical power companies in the United States. Exposures were assessed by panels composed of workers, hygienists, and managers at each company, who considered tasks performed by workers in 28 job categories and estimated weekly exposures in hours for each job. Poisson regression was used to examine mortality in relation to exposure to electrical insulating fluids containing PCBs, controlling for demographic and occupational factors. RESULTS: Neither all cause nor total cancer mortality was related to cumulative exposure to PCB insulating fluids. Mortality from malignant melanoma increased with exposure; rate ratios (RRs) relative to unexposed men for melanoma were 1.23 (95% confidence interval (95% CI) 0.56 to 2.52), 1.71 (0.68 to 4.28) and 1.93 (0.52 to 7.14) for men with < 2000, > 2000-10,000, and > 10,000 hours of cumulative exposure to PCB insulating fluids, respectively, without consideration of latency. Lagging exposure by 20 years yielded RRs of 1.29 (0.76 to 2.18), 2.56 (1.09 to 5.97), and 4.81 (1.49 to 15.50) for the same exposure levels. Mortality from brain cancer was modestly increased among men with < 2000 hours (RR 1.61, 95% CI 0.86 to 3.01) and > 2000-10,000 hours exposure (RR 1.79, 95% CI 0.81 to 3.95), but there were no deaths from brain cancer among the most highly exposed men. A lag of five years yielded slightly increased RRs. Mortality from liver cancer was not associated with exposure to PCB insulating fluids. CONCLUSIONS: This study was larger and provided more detailed information on exposure than past investigations of workers exposed to PCBs. The results suggest that PCBs cause cancer, with malignant melanoma being of particular concern in this industry.
Risk of cancer among paper recycling workers.
Authors: Rix B A , Villadsen E , Engholm G , Lynge E
Published: December 2008

OBJECTIVES: Studies in traditional paper mills have indicated an excess cancer risk, and mutagenic compounds have been identified in the industry. No studies have reported on risk of cancer in paper recycling. Therefore the cancer incidence in Danish paper recycling mills was investigated. METHODS: 5377 employees in five paper recycling plants were included in a historical cohort study. The workers had been employed in paper recycling in 1965-90, and the cohort was followed up until 31 December 1993. The expected number of cancer cases was calculated from national rates. RESULTS: There was significantly more pharyngeal cancer among male workers (seven observed (standardised incidence ratio (SIR) 3.33, 95% confidence interval (95% CI) 1.34 to 6.87)). There was slightly more lung cancer among male workers in production (39 observed, SIR 1.21, 95% CI 0.86 to 1.65). Risk of Hodgkin's disease was doubled in male production worker (four observed, SIR 1.90, 95% CI 0.51 to 4.85). CONCLUSIONS: The increased risk of pharyngeal cancer found in this study is interesting but may be influenced by confounders such as smoking and alcohol intake. This study also indicates an excess risk of Hodgkin's disease, which is in accordance with some studies in the traditional paper mills. As this is the first report on risk of cancer in paper recycling, further studies are needed.
Risk factors for carpal tunnel syndrome in a general population.
Authors: Nordstrom D L , Vierkant R A , DeStefano F , Layde P M
Published: December 2008

OBJECTIVE: To determine the individual, physical, and psychosocial risk factors for carpal tunnel syndrome in a general population. METHODS: Population based case-control study in Marshfield epidemiological study area in Wisconsin, USA. Cases were men and women aged 18-69 with newly diagnosed carpal tunnel syndrome (n = 206 (83.1%) of 248 eligible). Controls were a random sample of residents of the study area who had no history of diagnosed carpal tunnel syndrome (n = 211 (81.5%) of 259 eligible). Cases and controls were matched by age. Telephone interviews and reviews of medical records obtained height and weight, medical history, average daily hours of exposure to selected physical and organisational work factors, and self ratings on psychosocial work scales. RESULTS: In the final logistic regression model, five work and three non-work variables were associated with risk of carpal tunnel syndrome, after adjusting for age. For each one unit of increase in body mass index (kg/m2), risk increased 8% (odds ratio (OR) 1.08; 95% confidence interval (95% CI) 1.03 to 1.14). Having a previous musculoskeletal condition was positively associated with carpal tunnel syndrome (OR 2.54; 95% CI 1.03 to 6.23). People reporting the least influence at work had 2.86 times the risk (95% CI, 1.10 to 7.14) than those with the most influence at work. CONCLUSIONS: Carpal tunnel syndrome is a work related disease, although some important measures of occupational exposure, including keyboard use, were not risk factors in this general population study. The mechanism whereby a weight gain of about six pounds increases the risk of disease 8% requires explanation.
Neurological signs in relation to cancer in patients with asbestosis.
Authors: Juntunen J , Oksa P , Pukkala E , Laippala P
Published: December 2008

OBJECTIVE: To chart the subtle neurological abnormalities in patients with asbestosis relative to possible development of cancer. METHODS: In 1979-81 a standardised neurological examination was made of 115 patients with asbestosis who carried a high risk of occupational cancer and their cancer morbidity was analysed 15 years later. RESULTS: Slight disturbances of unknown aetiology were found in the central nervous system (CNS) of 33 and in the peripheral nervous system (PNS) of 41 patients. Of these 17 had disturbances of both the CNS and PNS. This cohort was followed up to the end of 1994. During this time 47 of the patients developed cancer. Statistical analyses showed that disturbances of the CNS such as psycho-organic syndrome, cerebellar dysfunction, and motor disturbances of unknown origin were significantly associated with cancer, whereas no such association was found for peripheral neuropathy. Interaction between the radiological progression of asbestosis and disturbances of the CNS was an even stronger predictor of cancer. CONCLUSIONS: It seems that slight disturbances of the CNS are predictors of development of cancer. Whether or not these disturbances are manifestations of involvement of a paraneoplastic nervous system or some factor associated with progression of asbestosis remains open.
Why and how to control for age in occupational epidemiology.
Authors: Consonni D , Bertazzi P A , Zocchetti C
Published: December 2008

In occupational epidemiology, the need to consider the age factor properly influences the choice of study design and analytical techniques. In most studies, age is viewed as a potential confounder. Age is strongly associated with end points of interest in occupational epidemiology (diseases, physiological characteristics, doses of xenobiotics, etc), but to measure age as a confounder it must be associated with the exposure under study. When the exposure of interest is time related-for example, duration of employment, time since first exposure, cumulative exposure-a strong intrinsic association with age can be anticipated, and age will behave as a (usually strong) confounder. When occupational exposures without a direct relation with age-for example, job, department, type of exposure-are evaluated, the degree and direction of confounding bias cannot be anticipated. Control of the confounding effect of age can be accomplished in the design phase of a study by way of randomisation, restriction, and matching. Randomisation is seldom viable in occupational settings. Restriction is rarely used in the case of age. Matching is often used in a case-control study as a method to increase the study efficiency, but it must be followed by proper matched or stratified analysis. Options for age adjustment in the analysis phase involve stratification and regression methods. In longitudinal studies the modified life table analysis is used to take into account the fact that subjects cross categories of age as the study proceeds. Stability of relative measures of effect over age strata favoured the greater use of relative risks than risk differences. In the presence of effect modification the influence of age should not be eliminated; its interaction with exposure should be explicitly considered.
Selection related to musculoskeletal complaints among employees.
Authors: de Zwart B C , Broersen J P , van der Beek A J , Frings-Dresen M H , Van Dijk F J
Published: December 2008

OBJECTIVES: To (a) describe differences in the outcome of cross sectional and longitudinal analysis on musculoskeletal complaints relative to age and work demands, and (b) to assess the entrance and drop out selection on musculoskeletal complaints among groups of employees relative to age and work demands. METHODS: A study population was selected on the basis of questionnaire data from periodical occupational health surveys of almost 45,000 employees collected between 1982 and 1993. From all companies within this data base that participated twice in company wide surveys four years apart, male employees were selected, and stratified for age and work demands. There were several populations: follow up (participation in both surveys); drop out (participation only in the first survey); entrance (participation only at the second survey); and two cross sectional populations (all participants at each survey). Prevalences of back complaints and turnover rates were analysed. RESULTS: Reported back complaints in the cross sectional analysis declined over the oldest age groups in heavy physical work versus a small increase in the longitudinal analysis. The age group 50-9 and back complaints were identified as predictors at the first survey for not participating at the second survey. Neither age nor work demands at the first survey indicated drop out among those employees with back complaints at the first survey. The effects of entrance selection on estimated prevalences were small. CONCLUSIONS: The results indicate that musculoskeletal disorders lead to selection out of work, affecting the validity of both cross sectional and longitudinal epidemiological studies. In future studies analyses of turnover figures on musculoskeletal complaints relative to work demands and age are recommended.
Spontaneous abortion in dry cleaning workers potentially exposed to perchloroethylene.
Authors: Doyle P , Roman E , Beral V , Brookes M
Published: December 2008

OBJECTIVES: To investigate the association between spontaneous abortion and work within dry cleaning units in the United Kingdom where the solvent perchloroethylene is used. METHODS: A retrospective occupational study of reproductive outcome in 7305 women aged 16 and 45 years, who were currently or previously employed in dry cleaning or laundry units in the United Kingdom. Data on workplace exposures and reproductive outcome were obtained by postal survey. A sample of reported spontaneous abortions was validated from medical records. Machine operator versus non-operator was used as a surrogate for exposure to perchloroethylene in dry cleaning units as no data on individual doses were available for women in this study. RESULTS: The response rate was higher for current workers of dry cleaning units (78%), than for past workers of dry cleaning units (46%). Similarly, the response for current laundry workers (65%) was higher than that for past laundry workers (40%). Overall, the reproductive characteristics of the respondents were similar to expectation. Examination of exposure at the time of pregnancy, however, showed that the rate of spontaneous abortion varied according to the type of work the women did during the pregnancy or in the three months before conception: being lowest for pregnancies not exposed to either dry cleaning or laundry work (10.9%), higher for those exposed to laundry work (13.4%), and higher still for those exposed to dry cleaning work (14.8%). Within the group of pregnancies exposed to dry cleaning, the proportion was higher if the woman reported that she worked as an operator at the time of the pregnancy (17.1%) rather than as a non-operator (11.6%). Adjusted odds ratios for the period 1980-95 showed that the risk was over 50% higher in operators than non-operators (p = 0.04). The physical demands of the two jobs are likely to be similar. A higher risk was found when work as a dry cleaning operator was compared with no work in either dry cleaning or laundry units during pregnancy. Exposure to dry cleaning as a non-operator was not associated with any excess risk. CONCLUSIONS: Women who worked in dry cleaning shops at the time of their pregnancy or in the three months before who described themselves as operators were about half as likely again to report that their pregnancy ended in a spontaneous abortion than women who described themselves as non-operators.
Vibrotactile sense and hand symptoms in blue collar workers in a manufacturing industry.
Authors: Flodmark B T , Lundborg G
Published: December 2008

OBJECTIVES: To study whether vibrotactile sense combined with questionnaires (subjective complaints) and a clinical examination (including scoring of the Stockholm workshop scale (sensorineural staging)) could serve as a screening procedure, in the health care service, for sensorineural symptoms. A group of blue collar workers exposed to vibration in a manufacturing industry (rock crushing plants) was used as the study group. Another group of workers not exposed to vibration but subjected to heavy manual work served as the control group. METHODS: Vibrotactile sense was determined. The index and the little fingers of both hands were investigated. A clinical examination was performed. Questionnaires were used for exposure data and for assessment of symptoms. RESULTS: Important findings were that impairment in vibrotactile sense correlated with impairment in grip force, cold sensitivity, and other sensorineural symptoms--such as numbness and tendency to drop items. Clinical findings such as Phalen's test and two point discrimination were related only in those workers with the poorest vibrotactile sense. There was a relation between vibrotactile sense and the Stockholm workshop scale (sensorineural staging) for the sensorineural symptoms. Muscle and joint problems were more often seen in workers with decreased vibrotactile sense. CONCLUSIONS: Tactilometry for assessment of vibrotactile sense is a useful tool in assessing and evaluating the severity of vibration induced neuromuscular symptoms and verifying the patients' clinical complaints. Heavy manual work without exposure to vibration may contribute to impairment of vibrotactile sense. The relation between impairment in vibrotactile sense and grip strength indicates that impaired sensory feedback may contribute to muscle weakness.
Childhood exposure to PM10: relation between personal, classroom, and outdoor concentrations.
Authors: Janssen N A , Hoek G , Harssema H , Brunekreef B
Published: December 2008

OBJECTIVES: To investigate the validity of outdoor concentrations of particulate matter < 10 microns diameter (PM10) as a measure of exposure in time series studies, and to study the extent to which differences between personal and outdoor PM10 concentrations can be explained. METHODS: Four to eight repeated measurements of personal and outdoor PM10 concentrations were conducted for 45 children, aged 10-12 years, from four schools in Wageningen and Amsterdam, The Netherlands. Repeated PM10 measurements in the classrooms were conducted in three of the schools. Averaging time was 24 hours for the personal and outdoor measurements, and eight hours (daytime) and 24 hours for the classroom measurements. For each child separately, personal exposures were related to outdoor concentrations in a regression analysis. The distribution of the individual correlation and regression coefficients was investigated. Information about factors that might influence personal exposures was obtained by questionnaire. RESULTS: Median Pearson's correlations between personal and outdoor concentrations were 0.63 for children with parents who did not smoke and 0.59 for children with parents who smoked. For children with parents who did not smoke, excluding days with exposure to environmental tobacco smoke (ETS) improved the correlation to a median R of 0.73. The mean personal PM10 concentration was 105 micrograms/m3; on average 67 micrograms/m3 higher than the corresponding outdoor concentrations. The main part of this difference could be attributed to exposure to ETS, to high PM10 concentrations in the classrooms, and to (indoor) physical activity. CONCLUSIONS: The results show a reasonably high correlation between repeated personal and outdoor PM10 measurements within children, providing support for the use of fixed site measurements as a measure of exposure to PM10 in epidemiological time series studies. The large differences between personal and outdoor PM10 concentrations probably result from a child's proximity to particle generating sources and particles resuspended by personal activities.
Survey of the use of personal protective equipment and prevalence of work related symptoms among dental staff.
Authors: Allsopp J , Basu M K , Browne R M , Burge P S , Matthews J B
Published: December 2008

OBJECTIVES: Dental instruments such as the right angle or straight handpiece, air turbine, and ultrasonic scaler have the ability to produce dental aerosols containing water, saliva, microorganisms, blood, tooth particles, lubricating oil, and restorative materials. The purpose of this study was to find out whether personal protective equipment (mask, glasses) was used by dental personnel, and to investigate possible work related disease in the dental profession. METHODS: Cross sectional data were collected with a self administered questionnaire sent to 69 randomly chosen general dental practices in the West Midlands Region. All members of the dental team completed questionnaires (dentists (n = 122); nurses (n = 115); hygienists (n = 86); and receptionists (n = 74) and answered questions on use of personal protective equipment and the prevalence of upper and lower respiratory tract, eye, and skin symptoms (reported and work related). Reception staff were included as a low exposure, control group. Also, a longitudinal study of dental hygienists was carried out on 31 people who had taken part in a similar study five years earlier. RESULTS: Use of a face mask and glasses differed between clinical groups with hygienists and nurses being the most and least prevalent users respectively. Although several reported symptoms were significantly more prevalent among clinical staff, only one work related symptom (skin rashes or itchy or dry skin) was reported by the clinical staff more than by the non-clinical receptionists. Among female clinical staff, age < 35 years and atopy were the factors that predisposed to work related symptoms. Also, reported symptoms were related to duration of use of instruments that generated aerosols. CONCLUSIONS: This study shows a low level of work related symptoms in dentistry, but highlights a group vulnerable to prolonged exposures to dental aerosols. It also supports the need for enforcement of the use of personal protective equipment among dental nurses.
Measurement of exposure to mouse urinary proteins in an epidemiological study.
Authors: Gordon S , Kiernan L A , Nieuwenhuijsen M J , Cook A D , Tee R D , Newman Taylor A J
Published: December 2008

OBJECTIVES: To develop an assay to measure airborne mouse urinary protein (MUP) and to assess the occupational exposure to MUP in the workforce of three establishments as part of an epidemiological study examining the influence of aeroallergen exposure on the development of allergic respiratory disease. METHODS: Personal air samples were collected from nine exposure groups during a workshift. A sensitive and reproducible competitive inhibition assay, which used rabbit antisera specific for MUP, was developed and used to measure the occupational exposure to MUP. RESULTS: The personal measurements of MUP showed that people with direct contact with mice (animal technicians) had the highest exposure followed in decreasing order by those working with anaesthetised animals or their tissue (postmortem workers and scientists) and those with indirect contact with mice (supervisors, office workers, and slide production workers). The only difference in concentrations of MUP between the three establishments were found for cage cleaners, which reflected differences in working practises for this exposure category. Air samples collected during the performance of specific tasks showed that high exposures to MUP were associated with handling mice, indirect contact with mice, and washing floors. CONCLUSIONS: Exposure to mouse urinary proteins has been measured in the occupational environment. This information can be used to determine the relation between exposure to MUP and the development of allergic and respiratory disease.
Methods for assessing the extent of exposure and effects of air pollution.
Authors: Krzyzanowski M
Published: December 2008

BACKGROUND AND OBJECTIVES: In many places in Europe, the ambient air pollution exceeds the levels considered to be safe for health. The objective of the paper is to review and summarise the methods of assessment of its impact on health, and to indicate the contributions of various research disciplines, particularly environmental epidemiology. METHODS: The framework for assessment of impact is based on a four stage model: assessment of release of pollutant; assessment of exposure; assessment of the consequence; and risk estimation. RESULTS: Epidemiology is crucial in providing the data for the assessment of consequence. The criteria that determine the use of epidemiological studies for this task include lack of bias, correct control of confounding, and measured estimates of exposure. At present, those criteria are easier to satisfy for studies of short term effects on health than for the delayed consequences of exposure, or exposure accumulated over a prolonged period. Combinations of results from various populations through meta-analysis of existing studies or conducting multicentre studies is often necessary to increase the reliability of the consequence assessment stage. CONCLUSION: To assess the impact on health systematically helps to focus on actions to limit air pollutants with the greatest impacts on human health and on the most affected populations. This method allows identification of the most pertinent questions which have to be answered by studies on relations between pollution and health and on exposure of populations to air pollutants. Epidemiology has considerable potential to contribute to this research.
Increased risk of lung cancer among male professional drivers in urban but not rural areas of Sweden.
Authors: Jakobsson R , Gustavsson P , Lundberg I
Published: December 2008

OBJECTIVES: To study the risk of lung cancer in different subgroups of professional drivers in urban and rural areas of Sweden. METHODS: Information on occupation and geographical region was obtained from the Swedish census of 1970 and data on the incidence of lung cancer between 1971 and 1984 from the National Swedish Cancer Registry. Professional drivers were separated into bus, taxi, and long and short distance lorry drivers. Comparisons of cumulative incidence of lung cancer were made between each particular group of drivers and gainfully employed men in the same region. RESULTS: Taxi drivers, and long and short distance lorry drivers in Stockholm County showed increased relative risks (RRs) of lung cancer with the highest risk among the short distance lorry drivers (RR 2.0, 95% confidence interval (95% CI) 1.5 to 2.6). These categories of drivers also showed increased risks in the other two large conurbations in Sweden. In the rest of the country (mainly rural areas) there were no increased RRs for any category of driver. The RR for bus drivers was not increased in any region. After adjustment for assumed differences in smoking habits the RRs remained significantly increased for lorry drivers in Stockholm but not for other groups of drivers in other areas. However, the RRs remained numerically higher in large conurbations than in rural regions for all groups of drivers. CONCLUSIONS: These findings suggest that some factors present in the urban environment play a substantial part in the excess of lung cancer among short distance lorry drivers in urban areas of Sweden. Exposure to motor exhaust fumes may have contributed to this excess.
Lung cancer mortality in a cohort of workers employed at a cadmium recovery plant in the United States: an analysis with detailed job histories.
Authors: Sorahan T , Lancashire R J
Published: December 2008

OBJECTIVES: To identify and measure any relations between occupational exposure to cadmium compounds (oxide, sulphide, and sulphate) and the risk of mortality from lung cancer. METHODS: The mortality experience of 571 male production workers from a cadmium recovery facility in the United States was investigated for the period 1940-82. All study subjects were first employed in the period 1926-69; they had all been employed for at least six months between 1 January 1940 and 31 December 1969. Newly abstracted detailed job histories for the period 1926-76 were combined with assessments of exposures to cadmium over time to develop individual estimates of cumulative exposure to cadmium (total exposure and exposures received both in the presence and absence of "high" exposures to arsenic trioxide). Poisson regression was used to investigate risks of mortality from lung cancer in relation to four concentrations of cumulative exposure to cadmium (< 400, 400-999, 1000-1999, > 2000 mg.m-3.days). RESULTS: After adjustment for age attained, year of hire, and Hispanic ethnicity, there was a significant positive trend (P < 0.05) between cumulative exposure to cadmium and risks of mortality from lung cancer. Relative to a risk of unity for the lowest exposure category (first level), risks were 2.30 (95% confidence interval (95% CI) 0.72 to 7.36), 2.83 (95% CI 0.75 to 10.72), and 3.88 (95% CI 1.04 to 14.46) for the second, third, and fourth categories, respectively. Similar findings were obtained after adjustment for age only. Trends were more pronounced when employment histories were lagged first by 10 years and then by 20 years. A separate analysis examined the independent effects of exposure to cadmium received in the presence of high exposures to arsenic trioxide (mainly cadmium oxide) and exposures to cadmium received without such exposure to arsenic (mainly cadmium sulphide and cadmium sulphate). A significant trend for a risk of lung cancer was found only for exposures to cadmium received in the presence of arsenic trioxide. CONCLUSIONS: Hypotheses which are consistent with the study findings include: (a) cadmium oxide in the presence of arsenic trioxide is a human lung carcinogen, (b) cadmium oxide and arsenic trioxide are human lung carcinogens and cadmium sulphate and cadmium sulphide are not (or they are less potent carcinogens), or (c) arsenic trioxide is a human lung carcinogen and cadmium oxide, cadmium sulphate, and cadmium sulphide are not. There were only 21 deaths from lung cancer available for this analysis and it is impossible to gauge which, if any, of these hypotheses are correct.
Occupational exposure to ionising radiation and mortality among workers of the former Spanish Nuclear Energy Board.
Authors: Rodríguez Artalejo F , Castaño Lara S , de Andrés Manzano B , García Ferruelo M , Iglesias Martín L , Calero J R
Published: December 2008

OBJECTIVES: Firstly, to ascertain whether mortality among workers of the former Spanish Nuclear Energy Board (Junta de Energía Nuclear-JEN) was higher than that for the Spanish population overall; and secondly, if this were so, to ascertain whether this difference was associated with exposure to ionising radiation. METHODS: A retrospective follow up of a cohort of 5657 workers was carried out for the period 1954-92. Cohort mortality was compared with that for the Spanish population overall, with standardised mortality ratios (SMRs) adjusted for sex, age, and calendar period. Also, Poisson models were used to analyse mortality from lung cancer in the cohort by level of exposure to ionising radiation. RESULTS: Workers' median and mean cumulative exposures were 4.04 and 11.42 mSv, respectively. Mean annual exposure was 1.33 mSv. Excess mortality due to bone tumours was found for the cohort as a whole (six deaths observed; SMR 2.95; 95% confidence interval (95% CI) 1.08 to 6.43). Among miners, excess mortality was found for non-malignant respiratory diseases (SMR 2.94; 95% CI 2.27 to 3.75), and for lung cancer bordering on statistical significance (SMR 1.50; 95% CI 0.96 to 2.23; P = 0.055). Relative risks of dying of lung cancer from ionising radiation in the dose quartiles 2, 3, and 4 versus the lowest dose quartile, were 1.00, 1.64, and 0.94, respectively. CONCLUSIONS: Excess mortality from lung cancer was found among JEN miners. Nevertheless, no clear relation was found between mortality from lung cancer and level of exposure to ionising radiation in the JEN cohort. Continued follow up of the cohort is required to confirm excess mortality from bone tumours.
Are aluminium potroom workers at increased risk of neurological disorders?
Authors: Sim M , Dick R , Russo J , Bernard B , Grubb P , Krieg E , Mueller C , McCammon C
Published: December 2008

OBJECTIVE: To determine whether long term potroom workers in an aluminium smelter are at increased risk of neurological disorders. METHODS: Cross sectional study of 63 current and former aluminium potroom workers first employed before 1970 and with at least 10 years of service. A group of 37 cast house and carbon plant workers with similar durations of employment and starting dates in the same smelter were used as controls. The prevalence of neurological symptoms was ascertained by questionnaire. Objective tests of tremor in both upper and lower limbs, postural stability, reaction time, and vocabulary were conducted. All subjects were examined by a neurologist. RESULTS: No significant differences in age, race, or education were found between the two groups. Although the potroom group had higher prevalences for all but one of the neurological symptoms, only three odds ratios (ORs) were significantly increased; for incoordination (OR 10.6), difficulty buttoning (OR 6.2), and depression (OR 6.2). Tests of arm or hand and leg tremor in both the visible and non-visible frequencies did not show any significant differences between the two groups. Testing of postural stability showed no definitive pattern of neurologically meaningful differences between the groups. There were no significant differences between the two groups in reaction time, vocabulary score, or clinical neurological assessment. CONCLUSIONS: The objective measures of neurological function provided little support for the finding of increased neurological symptom prevalences in the potroom workers, although increased symptoms may be an indicator of early, subtle neurological changes. The results provide no firm basis for concluding that neurological effects among long term potroom workers are related to the working environment, in particular aluminium exposure, in potrooms. These findings should be treated with caution due to the low participation of former workers and the possibility of information bias in the potroom group.