Showing papers in "Occupational and Environmental Medicine in 2007"

Temperature, temperature extremes, and mortality: a study of acclimatisation and effect modification in 50 US cities.

Abstract: Objectives: The authors examined the increase in mortality associated with hot and cold temperature in different locations, the determinants of the variability in effect estimates, and its implications for adaptation. Methods: The authors conducted a case-crossover study in 50 US cities. They used daily mortality and weather data for 6 513 330 deaths occurring during 1989–2000. Exposure was assessed using two approaches. First, the authors determined exposure to extreme temperatures using city-specific indicator variables based on the local temperature distribution. Secondly, they used piecewise linear variables to assess exposure to temperature on a continuous scale above/below a threshold. Effects of hot and cold temperature were examined in season-specific models. In a meta-analysis of the city-specific results, the authors examined several city characteristics as effect modifiers. Results: Mortality increases associated with both extreme cold (2-day cumulative increase 1.59% (95% CI 0.56 to 2.63)) and extreme heat (5.74% (95% CI 3.38 to 8.15)) were found, the former being especially marked for myocardial infarction and cardiac arrest deaths. The increase in mortality was less marked at less extreme temperatures. The effect of extreme cold (defined as a percentile) was homogeneous across cities with different climates, suggesting that only the unusualness of the cold temperature (and not its absolute value) had a substantial impact on mortality (that is, acclimatisation to cold). Conversely, heat effects were quite heterogeneous, with the largest effects observed in cities with milder summers, less air conditioning and higher population density. Adjustment for ozone led to similar results, but some residual confounding could be present due to other uncontrolled pollutants. Conclusions: The authors confirmed in a large sample of cities that both cold and hot temperatures increase mortality risk. These findings suggest that increases in heat-related mortality due to global warming are unlikely to be compensated for by decreases in cold-related mortality and that population acclimatisation to heat is still incomplete.

The Pro-Inflammatory Effects Of Low toxicity low solubility Particles, Nanoparticles and Fine Particles, on Epithelial Cells In Vitro: the Role of Surface Area.

Abstract: Rats exposed to high airborne mass concentrations of low solubility low toxicity particles (LSLTP) have been reported to develop lung disease such as fibrosis and lung cancer. These particles are regulated on a mass basis in occupational settings, but mass might not be the appropriate metric as animal studies have shown that nanoparticles (ultrafine particles) produce a stronger adverse effect than fine particles when delivered on an equal mass basis. The present study investigated whether the surface area of LSLTP is a better descriptor than mass of their ability to stimulate pro-inflammatory responses in vitro. In a human alveolar epithelial Type II-like cell line, A549, we measured interleukin-8 (IL-8) mRNA, IL-8 protein release and glutathione (GSH) depletion as markers of pro-inflammatory effects and oxidative stress after treatment with a range of LSLTP (fine and nanoparticles) and DQ12 quartz, a particle with a highly reactive surface. In all the assays, nanoparticle preparations of titanium dioxide [TiO2-np] and of Carbon Black [CB-np] produced much stronger pro-inflammatory responses than the same mass dose of fine TiO2 and CB. The results of the GSH assay confirmed that oxidative stress was involved in the response to all the particles, and two ultrafine metal dusts (cobalt and nickel) produced GSH depletion similar to TiO2-np, for similar surface-area dose. As expected, DQ12 quartz was more strongly inflammatory than the low toxicity dusts, on both a mass and surface area basis. Dose response relationships observed in the in vitro assays appeared to be directly comparable to dose response relationships in vivo when the doses were similarly standardised. Both sets of data suggested a threshold in dose measured as surface area of particles relative to the surface area of the exposed cells, at around 1 to 10 cm 2 /cm 2 . These findings are consistent with the hypothesis that surface area is a more appropriate dose metric than mass for the pro-inflammatory effects of LSLTP in vitro and in vivo and consequently that the high surface area of nanoparticles is a key factor in their inflammogenicity.

Wind turbine noise, annoyance and self-reported health and well-being in different living environments

Abstract: Aims The aims of this thesis were to describe and gain an understanding of how people who live in the vicinity of wind turbines are affected by wind turbine noise, and how individual, situational and visual factors, as well as sound properties, moderate the response. Methods A cross-sectional study was carried out in a flat, mainly rural area in Sweden, with the objective to estimate the prevalence of noise annoyance and to examine the dose-response relationship between Aweighted sound pressure levels (SPLs) and perception of and annoyance with wind turbine noise. Subjective responses were obtained through a questionnaire (n = 513; response rate: 68%) and outdoor, Aweighted SPLs were calculated for each respondent. To gain a deeper understanding of the observed noise annoyance, 15 people living in an area were interviewed using open-ended questions. The interviews were analysed using the comparative method of Grounded Theory (GT). An additional cross-sectional study, mainly exploring the influence of individual and situational factors, was carried out in seven areas in Sweden that differed with regard to terrain (flat or complex) and degree of urbanization (n = 765; response rate: 58%). To further explore the impact of visual factors, data from the two cross-sectional studies were tested with structural equation modelling. A proposed model of the influence of visual attitude on noise annoyance, also comprising the influence of noise level and general attitude, was tested among respondents who could see wind turbines versus respondents who could not see wind turbines from their dwelling, and respondents living in flat versus complex terrain. Results Dose-response relationships were found both for perception of noise and for noise annoyance in relation to A-weighted SPLs. The risk of annoyance was enhanced among respondents who could see at least one turbine from their dwelling and among those living in a rural in comparison with a suburban area. Noise from wind turbines was appraised as an intrusion of privacy among people who expected quiet and peace in their living environment. Negative experiences that led to feelings of inferiority added to the distress. Sound characteristics describing the amplitude modulated aerodynamic sound were appraised as the most annoying (swishing, whistling and pulsating/throbbing). Wind turbines were judged as environmentally friendly, efficient and necessary, but also as ugly and unnatural. Being negative towards the visual impact of the wind turbines on the landscape scenery, rather than towards wind turbines as such, was strongly associated with annoyance. Self-reported health impairment was not correlated to SPL, while decreased well-being was associated with noise annoyance. Indications of possible hindrance to psychophysiological restoration were observed. Conclusions Wind turbine noise is easily perceived and is annoying even at low A-weighted SPLs. This could be due to perceived incongruence between the characteristics of wind turbine noise and the background sound. Wind turbines are furthermore prominent objects whose rotational movement attracts the eye. Multimodal sensory effects or negative aesthetic response could enhance the risk of noise annoyance. Adverse reactions could possibly lead to stress-related symptoms due to prolonged physiological arousal and hindrance to psychophysiological restoration. The observed differences in prevalence of noise annoyance between living environments make it necessary to assess separate doseresponse relationships for different types of landscapes.

Bias in occupational epidemiology studies

Abstract: The design of occupational epidemiology studies should be based on the need to minimise random and systematic error. The latter is the focus of this paper, and includes selection bias, information bias and confounding. Selection bias can be minimised by obtaining a high response rate (and by appropriate selection of the control group in a case-control study). In general, it is important to ensure that information bias is minimised and is also non-differential (for example, that the misclassification of exposure is not related to disease status) by collecting data in a standardised manner. A major concern in occupational epidemiology studies usually relates to confounding, because exposure has not been randomly allocated, and the groups under study may therefore have different baseline disease risks. For each of these types of bias, the goal should be to avoid the bias by appropriate study design and/or appropriate control in the analysis. However, it is also important to attempt to assess the likely direction and strength of biases that cannot be avoided or controlled.

Psychosocial predictors of failure to return to work in non-chronic non-specific low back pain: a systematic review

Abstract: Objectives: To identify psychosocial predictors of failure to return to work in non-chronic (lasting less than 3 months) non-specific low back pain (NSLBP). Methods: A systematic review of prognostic studies was carried out. Medline, Embase, PsychINFO, CINAHL and PEDro electronic bibliographic databases up to April 2006 were searched. Included studies took baseline measures in the non-chronic phase of NSLBP (ie, within 3 months of onset), included at least one psychosocial variable and studied a sample in which at least 75% of participants had NSLBP. Baseline measures had to be used to predict at least one work-specific outcome. Results: The search identified 24 studies meeting the inclusion criteria. From these studies there is strong evidence that recovery expectation is predictive of work outcome and that depression, job satisfaction and stress/ psychological strain are not predictive of work outcome. There is moderate evidence that fear avoidance beliefs are predictive of work outcome and that anxiety is not predictive of work outcome. There is insufficient evidence to determine whether compensation or locus of control are predictive of work outcome. Conclusions: To predict work outcome in non-chronic NSLBP, psychosocial assessment should focus on recovery expectation and fear avoidance. More research is needed to determine the best method of measuring these constructs and to determine how to intervene when a worker has low recovery expectations.

Environmental risk factors for Parkinson's disease and parkinsonism: the Geoparkinson study

Abstract: Objective: To investigate the associations between Parkinson's disease and other degenerative parkinsonian syndromes and environmental factors in five European countries. Methods: A case-control study of 959 prevalent cases of parkinsonism (767 with Parkinson's disease) and 1989 controls in Scotland, Italy, Sweden, Romania and Malta was carried out. Cases were defined using the United Kingdom Parkinson's Disease Society Brain Bank criteria, and those with drug-induced or vascular parkinsonism or dementia were excluded. Subjects completed an interviewer-administered questionnaire about lifetime occupational and hobby exposure to solvents, pesticides, iron, copper and manganese. Lifetime and average annual exposures were estimated blind to disease status using a job-exposure matrix modified by subjective exposure modelling. Results were analysed using multiple logistic regression, adjusting for age, sex, country, tobacco use, ever knocked unconscious and family history of Parkinson's disease. Results: Adjusted logistic regression analyses showed significantly increased odds ratios for Parkinson's disease/parkinsonism with an exposure-response relationship for pesticides (low vs no exposure, odds ratio (OR) = 1.13, 95% CI 0.82 to 1.57, high vs no exposure, OR = 1.41, 95% CI 1.06 to 1.88) and ever knocked unconscious (once vs never, OR = 1.35, 95% CI 1.09 to 1.68, more than once vs never, OR = 2.53, 95% CI 1.78 to 3.59). Hypnotic, anxiolytic or antidepressant drug use for more than 1 year and a family history of Parkinson's disease showed significantly increased odds ratios. Tobacco use was protective (OR = 0.50, 95% CI 0.42 to 0.60). Analyses confined to subjects with Parkinson's disease gave similar results. Conclusions: The association of pesticide exposure with Parkinson's disease suggests a causative role. Repeated traumatic loss of consciousness is associated with increased risk.

Dose-effect relationships between manganese exposure and neurological, neuropsychological and pulmonary function in confined space bridge welders.

Abstract: Background: Although adverse neuropsychological and neurological health effects are well known among workers with high manganese (Mn) exposures in mining, ore-processing and ferroalloy production, the risks among welders with lower exposures are less well understood. Methods: Confined space welding in construction of a new span of the San Francisco-Oakland Bay Bridge without adequate protection was studied using a multidisciplinary method to identify the dose-effect relationship between adverse health effects and Mn in air or whole blood. Bridge welders (n = 43) with little or no personal protection equipment and exposed to a welding fume containing Mn, were administered neurological, neuropsychological, neurophysiological and pulmonary tests. Outcome variables were analysed in relation to whole blood Mn (MnB) and a Cumulative Exposure Index (CEI) based on Mn-air, duration and type of welding. Welders performed a mean of 16.5 months of welding on the bridge, were on average 43.8 years of age and had on average 12.6 years of education. Results: The mean time weighted average of Mn-air ranged from 0.11-0.46 mg/m(3) (55% > 0.20 mg/m(3)). MnB > 10 mu g/l was found in 43% of the workers, but the concentrations of Mn in urine, lead in blood and copper and iron in plasma were normal. Forced expiratory volume at 1s: forced vital capacity ratios (FEV1/FVC) were found to be abnormal in 33.3% of the welders after about 1.5 years of welding at the bridge. Mean scores of bradykinesia and Unified Parkinson Disease Rating Scale exceeded 4 and 6, respectively. Computer assisted tremor analysis system hand tremor and body sway tests, and University of Pennsylvania Smell Identification Test showed impairment in 38.5/61.5, 51.4 and 88% of the welders, respectively. Significant inverse dose-effect relationships with CEI and/or MnB were found for IQ (p <= 0.05), executive function (p <= 0.03), sustaining concentration and sequencing (p <= 0.04), verbal learning (p <= 0.01), working (p <= 0.04) and immediate memory (p <= 0.02), even when adjusted for demographics and years of welding before Bay Bridge. Symptoms reported by the welders while working were: tremors (41.9%); numbness (60.5%); excessive fatigue (65.1%); sleep disturbance (79.1%); sexual dysfunction (58.1%); toxic hallucinations (18.6%); depression (53.5%); and anxiety (39.5%). Dose-effect associations between CEI and sexual function (p < 0.05), fatigue (p < 0.05), depression (p < 0.01) and headache (p < 0.05) were statistically significant. Conclusions: Confined space welding was shown to be associated with neurological, neuropsychological and pulmonary adverse health effects. A careful enquiry of occupational histories is recommended for all welders presenting with neurological or pulmonary complaints, and a more stringent prevention strategy should be considered for Mn exposure due to inhalation of welding fume.

Effort-reward imbalance, procedural injustice and relational injustice as psychosocial predictors of health: Complementary or redundant models?

Abstract: Objective: Effort-reward imbalance at work is an established psychosocial risk factor but there are also newer conceptualisations, such as procedural injustice (decisions at work lack consistency, openness and input from all affected parties) and relational injustice (problems in considerate and fair treatment of employees by supervisors). The authors examined whether procedural injustice and relational injustice are associated with employee health in addition to, and in combination with, effort-reward imbalance. Methods: Prospective survey data from two cohorts related to public-sector employees: the 10-Town study (n = 18 066 (78% women, age range 19–62) and the Finnish Hospital Personnel study (n = 4833, 89% women, age range 20–60). Self-rated poor health, minor psychiatric morbidity and doctor-diagnosed depression were assessed at baseline (2000–2) and at follow-up (2004). To determine incident morbidity, baseline cases were excluded. Results: In multivariate models including age, sex, occupational status and all three psychosocial factors as predictors, high effort-reward imbalance and either high procedural injustice or high relational injustice were associated with increased morbidity at follow-up in both cohorts. After combining procedural and relational injustice into a single measure of organisational injustice, high effort-reward imbalance and high injustice were both independently associated with health. For all outcome measures, a combination of high effort-reward imbalance and high organisational injustice was related to a greater health risk than high effort-reward imbalance or injustice alone. Conclusion: Evidence from two independent occupational cohorts suggests that procedural and relational components of injustice, as a combined index, and effort-reward imbalance are complementary risk factors.

Long-term use of cellular phones and brain tumours - increased risk associated with use for > 10 years

Abstract: Aim: To evaluate brain tumour risk among long-term users of cellular telephones. Methods: One cohort study and 13 case-control studies were identified on this topic. Data were scrutinized for use of mobile phone for > 10 years and ipsilateral exposure if presented. Results: The cohort study was of limit value due to methodological shortcomings in the study. Of the 13 case-control studies, 9 gave results for > 10 years use or latency period. Most of these results were based on low numbers. Clearly an association with acoustic neuroma was found in four studies with two- to three-fold increased risk in the group with at least 10 years use of a mobile phone. No risk was found in one study, but the tumour size was significantly larger among users. Five studies gave results for malignant brain tumours in that latency group. All gave increased OR especially for ipsilateral exposure. Highest OR = 5.4, 95 % CI = 3.0-9.6 was calculated for high-grade glioma and ipsilateral exposure in one study. Conclusions: Results from present studies on use of mobile phones for > 10 years give a consistent pattern of an increased risk for acoustic neuroma and glioma, most pronounced for high-grade glioma. The risk is highest for ipsilateral exposure.

Interventions to prevent back pain and back injury in nurses: a systematic review

Abstract: A systematic literature review was undertaken to assess the effectiveness of interventions that aim to prevent back pain and back injury in nurses. Ten relevant databases were searched; these were examined and reference lists checked. Two reviewers applied selection criteria, assessed methodological quality and extracted data from trials. A qualitative synthesis of evidence was undertaken and sensitivity analyses performed. Eight randomised controlled trials and eight non-randomised controlled trials met eligibility criteria. Overall, study quality was poor, with only one trial classified as high quality. There was no strong evidence regarding the efficacy of any interventions aiming to prevent back pain and injury in nurses. The review identified moderate level evidence from multiple trials that manual handling training in isolation is not effective and multidimensional interventions are effective in preventing back pain and injury in nurses. Single trials provided moderate evidence that stress management programs do not prevent back pain and limited evidence that lumbar supports are effective in preventing back injury in nurses. There is conflicting evidence regarding the efficacy of exercise interventions and the provision of manual handling equipment and training. This review highlights the need for high quality randomised controlled studies to examine the effectiveness of interventions to prevent back pain and injury in nursing populations. Implications for future research are discussed.

Follow-up study of chrysotile textile workers: cohort mortality and exposure-response.

Abstract: Objectives: This report provides an update of the mortality experience of a cohort of South Carolina asbestos textile workers. Methods: A cohort of 3072 workers exposed to chrysotile in a South Carolina asbestos textile plant (1916–77) was followed up for mortality through 2001. Standardised mortality ratios (SMRs) were computed using US and South Carolina mortality rates. A job exposure matrix provided calendar time dependent estimates of chrysotile exposure concentrations. Poisson regression models were fitted for lung cancer and asbestosis. Covariates considered included sex, race, age, calendar time, birth cohort and time since first exposure. Cumulative exposure lags of 5 and 10 years were considered by disregarding exposure in the most recent 5 and 10 years, respectively. Results: A majority of the cohort was deceased (64%) and 702 of the 1961 deaths occurred since the previous update. Mortality was elevated based on US referent rates for a priori causes of interest including all causes combined (SMR 1.33, 95% CI 1.28 to 1.39); all cancers (SMR 1.27, 95% CI 1.16 to 1.39); oesophageal cancer (SMR 1.87, 95% CI 1.09 to 2.99); lung cancer (SMR 1.95, 95% CI 1.68 to 2.24); ischaemic heart disease (SMR 1.20, 95% CI 1.10 to 1.32); and pneumoconiosis and other respiratory diseases (SMR 4.81, 95% CI 3.84 to 5.94). Mortality remained elevated for these causes when South Carolina referent rates were used. Three cases of mesothelioma were observed among cohort members. Exposure-response modelling for lung cancer, using a linear relative risk model, produced a slope coefficient of 0.0198 (fibre-years/ml) (standard error 0.00496), when cumulative exposure was lagged 10 years. Poisson regression modelling confirmed significant positive relations between estimated chrysotile exposure and lung cancer and asbestosis mortality observed in previous updates of this cohort. Conclusions: This study confirms the findings from previous investigations of excess mortality from lung cancer and asbestosis and a strong exposure-response relation between estimated exposure to chrysotile and mortality from lung cancer and asbestosis.

Multidisciplinary consensus on the terminology and classification of complaints of the arm, neck and/or shoulder

Abstract: Background: There is no universally accepted way of labelling or defining upper-extremity musculoskeletal disorders. A variety of names are used and many different classification systems have been introduced. Objective: To agree on an “unambiguous language” concerning the terminology and classification that can be used by all relevant medical and paramedical disciplines in the Netherlands. Methods: A Delphi consensus strategy was initiated. The outcomes of a multidisciplinary conference were used as a starting point. In total, 47 experts in the field of upper-extremity musculoskeletal disorders were delegated by 11 medical and paramedical professional associations to form the expert panel for the Delphi consensus strategy. Each Delphi round consisted of a questionnaire, an analysis and a feedback report. Results: After three Delphi rounds, consensus was achieved. The experts reported the consensus in a model. This so-called CANS model describes the term, definition and classification of complaints of arm, neck and/or shoulder (CANS) and helps professionals to classify patients unambiguously. CANS is defined as “musculoskeletal complaints of arm, neck and/or shoulder not caused by acute trauma or by any systemic disease”. The experts classified 23 disorders as specific CANS, because they were judged as diagnosable disorders. All other complaints were called non-specific CANS. In addition, the experts defined “alert symptoms” on the top of the model. Conclusions: The use of the CANS model can increase accurate and meaningful communication among healthcare workers, and may also have a positive influence on the quality of scientific research, by enabling comparison of data of different studies.

Short-term effects of ozone air pollution on ischaemic stroke occurrence: a case-crossover analysis from a 10-year population-based study in Dijon, France.

Abstract: Objective: To evaluate the association between air pollutants and the occurrence of acute stroke from 10-year population-based study. Methods: The daily stroke count was obtained from Dijon Stroke Register between March 1994 and December 2004. The register recorded all first-ever strokes among residents of Dijon (150 000 inhabitants) in France, using standard diagnostic criteria. Pollutant concentrations (SO 2 , CO, NO 2, O 3 and PM 10 ) were measured hourly. A bi-directional case-crossover design was used to examine the association between air pollutant and stroke onset. The conditional logistic regression model included the meteorological parameters (temperature, relative humidity), influenza epidemics and holidays. Results: The authors collected 493 large artery infarcts, 397 small artery infarcts, 530 cardio-embolic infarcts, 67 undeterminate infarcts, 371 transient ischaemic attacks and 220 haemorrhagic strokes. For single-pollutant model and for a 10 mg/m 3 increase of O 3 exposure, a positive association was observed only in men, over 40 years of age, between ischaemic stroke occurrence and O 3 levels with 1-day lag, (OR 1.133, 95% CI 1.052 to 1.220) and 0-day lag (OR 1.058, 95% CI 0.987 to 1.134). No significant associations were found for haemorrhagic stroke. In two-pollutant models, the effects of O 3 remained significant after each of the other pollutants were included in the model, in particular with PM 10 . A significant association was observed for ischaemic strokes of large arteries (p = 0.02) and for transient ischaemic attacks (p = 0.01). Moreover, the authors found an exposure-response relations between O 3 exposure and ischaemic stroke (test for trend, p = 0.01). An increase in association in men with several cardiovascular risk factors (smoker, dyslipidemia and hypertension) was also observed. Conclusion: These observational data argue for an association between ischaemic stroke occurrence and O 3 pollution levels; these results still need to be confirmed by other studies.

Short-term associations between fine and coarse particles and hospital admissions for cardiorespiratory diseases in six French cities.

Abstract: Objectives: Little is known about the potential health effects of the coarse fraction of ambient particles The aim of this study is to estimate the links between fine (PM25) and coarse particle (PM25210) levels and cardiorespiratory hospitalisations in six French cities during 2000–2003 Methods: Data on the daily numbers of hospitalisations for respiratory, cardiovascular, cardiac and ischaemic heart diseases were collected Associations between exposure indicators and hospitalisations were estimated in each city using a Poisson regression model, controlling for confounding factors (seasons, days of the week, holidays, influenza epidemics, pollen counts, temperature) and temporal trends City-specific findings were combined to obtain excess relative risks (ERRs) associated with a 10 mg/m 3 increase in PM25 and PM25210 levels Results: We found positive associations between indicators of particulate pollution and hospitalisations for respiratory infection, with an ERR of 44% (95% CI 09 to 80) for PM25210 and 25% (95% CI 01 to 48) for PM25 Concerning respiratory diseases, no association was observed with PM25, whereas positive trends were found with PM25210, with a significant association for the 0– 14-year-old age group (ERR 62%, 95% CI 04 to 123) Concerning cardiovascular diseases, positive associations were observed between PM25 levels and each indicator, although some did not reach significance; trends with PM25210 were weaker and non-significant except for ischaemic heart disease in the elderly (ERR 64%, 95% CI 16 to 114) Conclusions: In accordance with other studies, our results indicate that the coarse fraction may have a stronger effect than the fine fraction on some morbidity endpoints, especially respiratory diseases

Work patterns and fatigue-related risk among junior doctors.

Abstract: Background: To reduce fatigue-related risk among junior doctors, recent initiatives in Europe and the USA have introduced limits on work hours. However, research in other industries has highlighted that other aspects of work patterns are important in generating fatigue, in addition to total work hours. The Australian Medical Association AMA has proposed a more comprehensive fatigue risk management approach. Objectives: To evaluate the work patterns of New Zealand junior doctors based on the AMA approach, examining relationships between different aspects of work and fatigue-related outcomes. Methods: An anonymous questionnaire mailed to all house officers and registrars dealt with demographics, work patterns, sleepiness, fatigue-related clinical errors, and support for coping with work demands. Each participant was assigned a total fatigue risk score combining 10 aspects of work patterns and sleep in the preceding week. Results: The response rate was 63 1366 questionnaires from doctors working 40 hours a week. On fatigue measures, 30 of participants scored as excessively sleepy Epworth Sleepiness Score >10, 24 reported falling asleep driving home since becoming a doctor, 66 had felt close to falling asleep at the wheel in the past 12 months, and 42 recalled a fatigue-related clinical error in the past 6 months. Night work and schedule instability were independently associated with more fatigue measures than was total hours worked, after controlling for demographic factors, The total risk score was a significant independent risk factor for all fatigue measures, in a dose-dependent manner all p Conclusions: To reduce fatigue-related risk among junior doctors, account must be taken of factors in addition to total hours of work and duration of rest breaks. The AMA fatigue risk assessment model offers a useful example of a more comprehensive approach.

Occupational risk factors in Alzheimer's disease: a review assessing the quality of published epidemiological studies.

Abstract: Epidemiological evidence of an association between Alzheimer's disease (AD) and the most frequently studied occupational exposures—pesticides, solvents, electromagnetic fields (EMF), lead and aluminium—is inconsistent. Epidemiological studies published up to June of 2003 were systematically searched through PubMed and Toxline. Twenty‐four studies (21 case–control and 3 cohort studies) were included. Median GQI was 36.6% (range 19.5–62.9%). Most of the case–control studies had a GQI of <50%. The study with the highest score was a cohort study. Likelihood of exposure misclassification bias affected 18 of the 24 studies. Opportunity for bias arising from the use of surrogate informants affected 17 studies, followed by disease misclassification (11 studies) and selection bias (10 studies). Eleven studies explored the relationship of AD with solvents, seven with EMF, six with pesticides, six with lead and three with aluminium. For pesticides, studies of greater quality and prospective design found increased and statistically significant associations. For the remaining occupational agents, the evidence of association is less consistent (for solvents and EMF) or absent (for lead and aluminium).

Occupational exposure to particulate air pollution and mortality due to ischaemic heart disease and cerebrovascular disease.

Abstract: OBJECTIVES: A growing number of epidemiological studies are showing that ambient exposure to particulate matter air pollution is a risk factor for cardiovascular disease; however, whether occupational exposure increases this risk is not clear. The aim of the present study was to examine whether occupational exposure to particulate air pollution increases the risk for ischaemic heart disease and cerebrovascular disease. METHODS: The study population was a cohort of 176,309 occupationally exposed Swedish male construction workers and 71,778 unexposed male construction workers. The definition of exposure to inorganic dust (asbestos, man-made mineral fibres, dust from cement, concrete and quartz), wood dust, fumes (metal fumes, asphalt fumes and diesel exhaust) and gases and irritants (organic solvents and reactive chemicals) was based on a job-exposure matrix with focus on exposure in the mid-1970s. The cohort was followed from 1971 to 2002 with regard to mortality to ischaemic heart disease and cerebrovascular disease. Relative risks (RR) were obtained by the person-years method and from Poisson regression models adjusting for baseline values of blood pressure, body mass index, age and smoking habits. RESULTS: Any occupational particulate air pollution was associated with an increased risk for ischemic heart disease (RR 1.13, 95% CI 1.07 to 1.19), but there was no increased risk for cerebrovascular disease (RR 0.97, 95% CI 0.88 to 1.07). There was an increased risk for ischaemic heart disease and exposure to inorganic dust (RR 1.07, 95% CI 1.03 to 1.12) and exposure to fumes (RR 1.05, 95% CI 1.00 to 1.10), especially diesel exhaust (RR 1.18, 95% CI 1.13 to 1.24). There was no significantly increased risk for cerebrovascular disease and exposure to inorganic dust, fumes or wood dust. CONCLUSIONS: Occupational exposure to particulate air pollution, especially diesel exhaust, among construction workers increases the risk for ischaemic heart disease.

The use of salivary biomarkers in occupational and environmental medicine

Abstract: The use of saliva as a diagnostic fluid is a relatively recent trend. This is not surprising when one considers its many advantages and the fact that saliva contains a wide array of constituents.1 Saliva collection is non-invasive compared with phlebotomy, and, as a result, more acceptable to patients. As obtaining saliva is easy, self-collection after instruction is possible and there is no need for trained staff. Moreover, it does not carry the risk of needle-stick injuries. Saliva collection is also less likely to cause stress compared with other invasive procedures such as phlebotomy, an important consideration when researching biomarkers of stress. Lastly, saliva samples can reflect real-time levels of biomarkers, unlike other biological fluids, such as urine, which is stored in the bladder for a few hours before sampling. A wide range of biomarkers is measurable in saliva, including heavy metals (eg, lead), hormones (eg, cortisol, dehydroxyepiandrosterone (DHEA)), toxins and their metabolites (eg, cotinine), enzymes (eg, lysozyme, α-amylase), immunoglobulins (eg, IgA), other proteins (eg, eosinophil cationic protein) and DNA. Researchers are also studying the proteomic components of saliva in the hope of identifying novel biomarkers of disease.2,3 A search of PubMed using the medical subject heading terms “saliva” and “biological markers” showed an increase in the number of studies using salivary biomarkers in the past decade (fig 1). However, when a search using the terms “saliva”, “markers” and “occupation” was performed, the numbers of occupational health papers using salivary markers lagged far behind. Of the 20 papers obtained from the second search, a review of abstracts showed that only 11 had actually used saliva biomarkers in occupational health research. These 11 papers were classified according to areas of occupational health research and the biomarker studied (table 1). The subsequent part of this paper will discuss these …

Occupational risk factors for asthma among nurses and related healthcare professionals in an international study.

Abstract: Objective: The authors examined the relations between self-reported work tasks, use of cleaning products and latex glove use with new-onset asthma among nurses and other healthcare workers in the European Community Respiratory Health Survey (ECRHS II). Methods: In a random population sample of adults from 22 European sites, 332 participants reported working in nursing and other related healthcare jobs during the nine-year ECRHS II follow-up period and responded to a supplemental questionnaire about their principal work settings, occupational tasks, products used at work and respiratory symptoms. Poisson regression models with robust error variances were used to compare the risk of new-onset asthma among healthcare workers with each exposure to that of respondents who reported professional or administrative occupations during the entire follow-up period (n=2481). Results: Twenty (6%) healthcare workers and 131 (5%) members of the referent population reported new-onset asthma. Compared to the referent group, the authors observed increased risks among hospital technicians (RR 4.63; 95% Cl 1.87 to 11.5) and among those using ammonia and/or bleach at work (RR 2.16; 95% Cl 1.03 to 4.53). Conclusions: In the ECRHS II cohort, hospital technicians and other healthcare workers experience increased risks of new-onset current asthma, possibly due to specific products used at work.

Gene-environment interactions in parkinsonism and Parkinson’s disease: the Geoparkinson study

Abstract: Objectives: To investigate associations of Parkinson's disease (PD) and parkinsonian syndromes with polymorphic genes that influence metabolism of either foreign chemical substances or dopamine and to seek evidence of gene-environment interaction effects that modify risk. Methods: A case-control study of 959 prevalent cases of parkinsonism (767 with PD) and 1989 controls across five European centres. Occupational hygienists estimated the average annual intensity of exposure to solvents, pesticides and metals, (iron, copper, manganese), blind to disease status. CYP2D6, PON1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, CYP1B1, MAO-A, MAO-B, SOD 2, EPHX, DATl, DRD2 and NAT2 were genotyped. Results were analysed using multiple logistic regression adjusting for key confounders. Results: There was a modest but significant association between MAO-A polymorphism in males and disease risk (G vs T, OR 1.30, 95% C1 1.02 to 1.66, adjusted). The majority of gene-environment analyses did not show significant interaction effects. There were possible interaction effects between GSTM1 null genotype and solvent exposure (which were stronger when limited to PD cases only). Conclusions: Many small studies have reported associations between genetic polymorphisms and PD. Fewer have examined gene-environment interactions. This large study was sufficiently powered to examine these aspects. GSTM1 null subjects heavily exposed to solvents appear to be at increased risk of PD. There was insufficient evidence that the other gene-environment combinations investigated modified disease risk, suggesting they contribute little to the burden of PD.

Incidence of hand eczema in female Swedish hairdressers

Abstract: Objective: To estimate the occurrence of hand eczema in hairdressers in Sweden. Methods: The occurrence of hand eczema was estimated in a Swedish longitudinal retrospective cohort study including all female graduates from vocational schools for hairdressers from 1970 to 1995. A stratified sample from the general population acted as controls. A self-administered questionnaire including questions on the occurrence of hand eczema, skin atopy, working periods and number of hair treatments performed per week was sent to the participants. Incidence rate ratios (IRRs) of hand eczema were estimated. Results: The incidence rate of hand eczema in hairdressers was 23.8 cases/1000 person-years, whereas in hairdressers who were aged Conclusion: Hairdressers are highly exposed to skin-damaging substances. The self-reported incidence of hand eczema was substantially higher in female hairdressers than in controls from the general population and than that found previously in register-based studies. For many individuals, onset of hand eczema occurs early in life. Only about 10% of the hand eczema cases among hairdressers would be prevented if no one with skin atopy entered the trade.

Work-organisational and personal factors associated with upper body musculoskeletal disorders among sewing machine operators

Abstract: Objective : To assess the contribution of work-organisational and personal factors to the prevalence of work-related musculoskeletal disorders (WMSDs) among garment workers in Los Angeles. Methods : This is a cross-sectional study of self-reported musculoskeletal symptoms among 520 sewing machine operators from 13 garment industry sewing shops. Detailed information on work-organisational factors, personal factors, and musculoskeletal symptoms were obtained in face-to-face interviews. The outcome of interest, upper body WMSD, was defined as a worker experiencing moderate or severe musculoskeletal pain. Unconditional logistic regression models were adopted to assess the association between both work-organisational factors and personal factors and the prevalence of musculoskeletal pain. Results : The prevalence of moderate or severe musculoskeletal pain in the neck/shoulder region was 24% and for distal upper extremity it was 16%. Elevated prevalence of upper body pain was associated with age less than 30 years, female gender, Hispanic ethnicity, being single, having a diagnosis of a MSD or a systemic illness, working more than 10 years as a sewing machine operator, using a single sewing machine, work in large shops, higher work–rest ratios, high physical exertion, high physical isometric loads, high job demand, and low job satisfaction. Conclusion : Work-organisational and personal factors were associated with increased prevalence of moderate or severe upper body musculoskeletal pain among garment workers. Owners of sewing companies may be able to reduce or prevent WMSDs among employees by adopting rotations between different types of workstations thus increasing task variety; by either shortening work periods or increasing rest periods to reduce the work–rest ratio; and by improving the work-organisation to control psychosocial stressors. The findings may guide prevention efforts in the garment sector and have important public health implications for this workforce of largely immigrant labourers.

Criteria and methods used for the assessment of fitness for work: a systematic review

Abstract: The main findings from reports published in scientific journals on the criteria and methods used to assess fitness for work were reviewed. Systematic searches were made using internet engine searches (1966-2005) with related keywords. 39 reports were identified, mostly from the US and western Europe. Assessment of fitness for work is defined by most as the evaluation of a worker's capacity to work without risk to their own or others' health and safety. It is mainly assessed at recruitment (pre-offer or post-offer), and when changes of work or health conditions occur. Five main criteria used by occupational doctors to evaluate fitness for work were identified: the determination of worker's capacity and worker's risk in relation to his or her workplace, as well as ethical, economic and legal criteria. Most authors agreed that assessment tools used need to be specific and cost-effective, and probably none gives unequivocal answers. Outcomes from fitness for work assessments range from "fit" to "unfit", with other possible intermediate categories such as "fit subject to work modifications", "fit with restrictions" or "conditionally fit (temporarily, permanently)". Workplace modifications to improve or adjust working conditions must always be considered. There is confusion about the decision-making process to be used to judge about fitness for work. There is very scarce scientific evidence based on empirical data, probably because there are no standard or valid methodologies for all professions and circumstances.

Self‐reported health problems and sickness absence in different age groups predominantly engaged in physical work

Abstract: Objectives To study the associations between self-reported health problems and sickness absence from work. Methods The results of a questionnaire survey were combined with archival data of sickness absence of 1341 employees (88% males; 62% blue-collar) in the construction, service and maintenance work within one corporation in Finland. Sex, age, and occupational grading were controlled as confounders. Zero-inflated negative binomial (ZINB) regression model was used in the statistical analysis of sickness absence data. Results The prevalence of self-reported health problems increased with age, from 23% in the 18-30 year old to 54% in the 55-61 year old. However, in the age group 18 to 30 years, 71% had been absent from work and in the age group 55 to 61 years this proportion was 53%. When health problems and occupational grading were accounted for in the ZINB model, age as such was not associated with the number of days on sick leave, but the young workers still had higher propensity for (any) sickness absence than the old. Self-rated future working ability and musculoskeletal impairment were strong determinants of sickness absence. Among those susceptible to have sick leaves, the estimated mean number of absence days increased by 14% for each rise of 1 unit of the impairment score (scale 0 to 10). Conclusions Young subjects had surprisingly high probability for sickness absence although they reported better health than their older colleagues. Higher total count of absence days was found among subjects reporting health problems and poorer working ability, regardless of age, sex and occupational grade. These findings have implications both for the management and health care system in the prevention of work disability.

Interventions for the prevention and management of neck/upper extremity musculoskeletal conditions: a systematic review

Abstract: Considered from medical, social or economic perspectives, the cost of musculoskeletal injuries experienced in the workplace is substantial, and there is a need to identify the most efficacious interventions for their effective prevention, management and rehabilitation. Previous reviews have highlighted the limited number of studies that focus on upper extremity intervention programmes. The aim of this study was to evaluate the findings of primary, secondary and/or tertiary intervention studies for neck/upper extremity conditions undertaken between 1999 and 2004 and to compare these results with those of previous reviews. Relevant studies were retrieved through the use of a systematic approach to literature searching and evaluated using a standardised tool. Evidence was then classified according to a "pattern of evidence" approach. Studies were categorised into subgroups depending on the type of intervention: mechanical exposure interventions; production systems/organisational culture interventions and modifier interventions. 31 intervention studies met the inclusion criteria. The findings provided evidence to support the use of some mechanical and modifier interventions as approaches for preventing and managing neck/upper extremity musculoskeletal conditions and fibromyalgia. Evidence to support the benefits of production systems/organisational culture interventions was found to be lacking. This review identified no single-dimensional or multi-dimensional strategy for intervention that was considered effective across occupational settings. There is limited information to support the establishment of evidence-based guidelines applicable to a number of industrial sectors.

Brain tumours and exposure to pesticides: a case–control study in southwestern France

Abstract: Background: Brain tumours are often disabling and rapidly lethal; their aetiology is largely unknown. Among potential risk factors, pesticides are suspected. Objective: To examine the relationship between exposure to pesticides and brain tumours in adults in a population-based case–control study in southwestern France. Methods: Between May 1999 and April 2001, 221 incident cases of brain tumours and 442 individually matched controls selected from the general population were enrolled. Histories of occupational and environmental exposures, medical and lifestyle information were collected. A cumulative index of occupational exposure to pesticides was created, based on expert review of lifelong jobs and tasks. Separate analyses were performed for gliomas and meningiomas. Results: A non-statistically significant increase in risk was found for brain tumours when all types of occupational exposure to pesticides were considered (OR = 1.29, 95% CI 0.87 to 1.91) and slightly higher but still non-statistically significant when gliomas were considered separately (OR = 1.47, 95% CI 0.81 to 2.66). In the highest quartile of the cumulative index, a significant association was found for brain tumours (OR = 2.16, 95% CI 1.10 to 4.23) and for gliomas (OR = 3.21, 95% CI 1.13 to 9.11), but not for meningiomas. A significant increase in risk was also seen for the treatment of home plants (OR = 2.24, 95% CI 1.16 to 4.30) owing to environmental exposure to pesticides. Conclusions: These data suggest that a high level of occupational exposure to pesticides might be associated with an excess risk of brain tumours, and especially of gliomas.

Work-related injury among Direct Care occupations in British Columbia, Canada

Abstract: Objectives: To examine how injury rates and injury types differ across direct care occupations in relation to the healthcare settings in British Columbia, Canada. Methods: Data were derived from a standardised operational database in three BC health regions. Injury rates were defined as the number of injuries per 100 full-time equivalent FTE positions. Poisson regression, with Generalised Estimating Equations, was used to determine injury risks associated with direct care occupations registered nurses RNs, licensed practical nurses LPNs and care aides CAs by healthcare setting acute care, nursing homes and community care. Results: CAs had higher injury rates in every setting, with the highest rate in nursing homes 37.0 injuries per 100 FTE. LPNs had higher injury rates 30.0 within acute care than within nursing homes. Few LPNs worked in community care. For RNs, the highest injury rates 21.9 occurred in acute care, but their highest 13.0 musculoskeletal injury MSI rate occurred in nursing homes. MSIs comprised the largest proportion of total injuries in all occupations. In both acute care and nursing homes, CAs had twice the MSI risk of RNs. Across all settings, puncture injuries were more predominant for RNs 21.3 of their total injuries compared with LPNs 14.4 and CAs 3.7. Skin, eye and respiratory irritation injuries comprised a larger proportion of total injuries for RNs 11.1 than for LPNs 7.2 and CAs 5.1. Conclusions: Direct care occupations have different risks of occupational injuries based on the particular tasks and roles they fulfil within each healthcare setting. CAs are the most vulnerable for sustaining MSIs since their job mostly entails transferring and repositioning tasks during patient/resident/client care. Strategies should focus on prevention of MSIs for all occupations as well as target puncture and irritation injuries for RNs and LPNs.

Hospital injury rates in relation to socioeconomic status and working conditions

Abstract: Objectives: To describe the risk of work injury by socioeconomic status (SES) in hospital workers, and to assess whether SES gradient in injury risk is explained by differences in psychosocial, ergonomic or organisational factors at work. Methods: Workforce rosters and Occupational Safety and Health Administration injury logs for a 5-year period were obtained from two hospitals in Massachusetts. Job titles were classified into five SES strata on the basis of educational requirements and responsibilities: administrators, professionals, semiprofessionals, skilled and semiskilled workers. 13 selected psychosocial, ergonomic and organisational exposures were assigned to the hospital jobs through the national O*NET database. Rates of injury were analysed as frequency records using the Poisson regression, with job title as the unit of analysis. The risk of injury was modelled using SES alone, each exposure variable alone and then each exposure variable in combination with SES. Results: An overall annual injury rate of 7.2 per 100 full-time workers was estimated for the two hospitals combined. All SES strata except professionals showed a significant excess risk of injury compared with the highest SES category (administrators); the risk was highest among semiskilled workers (RR 5.3, p Conclusions: A strong gradient in the risk of injury by SES was reported in a sample population of hospital workers, which was greatly attenuated by adjusting for psychosocial and ergonomic workplace exposures, indicating that a large proportion of that gradient can be explained by differences in working conditions.

The impact of OSHA recordkeeping regulation changes on occupational injury and illness trends in the US: a time-series analysis

Abstract: Objectives: The Survey of Occupational Injuries and Illnesses (SOII), based on Occupational Safety and Health Administration (OSHA) logs, indicates that the number of occupational injuries and illnesses in the US has steadily declined by 35.8% between 1992–2003. However, major changes to the OSHA recordkeeping standard occurred in 1995 and 2001. The authors assessed the relation between changes in OSHA recordkeeping regulations and the trend in occupational injuries and illnesses. Methods: SOII data available from the Bureau of Labor Statistics for years 1992–2003 were collected. The authors assessed time series data using join-point regression models. Results: Before the first major recordkeeping change in 1995, injuries and illnesses declined annually by 0.5%. In the period 1995–2000 the slope declined by 3.1% annually (95% CI −3.7% to −2.5%), followed by another more precipitous decline occurring in 2001–2003 (−8.3%; 95% CI −10.0% to −6.6%). When stratifying the data, the authors continued to observe significant changes occurring in 1995 and 2001. Conclusions: The substantial declines in the number of injuries and illnesses correspond directly with changes in OSHA recordkeeping rules. Changes in employment, productivity, OSHA enforcement activity and sampling error do not explain the large decline. Based on the baseline slope (join-point regression analysis, 1992–4), the authors expected a decline of 407 964 injuries and illnesses during the period of follow-up if no intervention occurred; they actually observed a decline of 2.4 million injuries and illnesses of which 2 million or 83% of the decline can be attributed to the change in the OSHA recordkeeping rules.

Job adjustment and absence from work in mid-pregnancy in the Norwegian Mother and Child Cohort Study (MoBa)

Abstract: Background: Pregnant women at work have special needs, and sick leave is common. However, job adjustment in pregnancy is addressed in European legislation. Our main objective was to examine if job adjustment was associated with reduced absence. Methods: This study is based on the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health. 28 611 employed women filled in questionnaires in weeks 17 and 30 in pregnancy. The risk of absence for more than 2 weeks was studied among those who were not absent in week 17 (n = 22 932), and the probability of return to work in week 30 among those who were absent in week 17 (n = 5679). Data were based on self-report. The influence of job adjustment (three categories: not needed, needed but not obtained, needed and obtained) was analysed in additive models in multivariable binomial regression. Associations with other job characteristics and work environment factors were also analysed. Results: The risk of absence for more than 2 weeks was 0.308 and the probability of return to work was 0.137. Compared with women who needed but did not achieve job adjustment, obtained job adjustment was associated with a 0.107 decreased risk of absence (95% confidence interval 0.090 to 0.125) in a model including other job characteristics and work environment factors. Job adjustment was correspondingly associated with a 0.041 (0.023 to 0.059) increased probability of return to work. Absence was associated with adverse work environment, whereas the opposite pattern was found for return to work among those who started off being absent. Conclusions: Job adjustment was associated with reduced absence from work in pregnancy. Results should be interpreted cautiously because of low participation in MoBa and potential information bias from self-reported data.