Compliance with follow-up after occupational exposure to hepatitis C

BACKGROUND: Accidental percutaneous exposure to blood containing hepatitis C virus (HCV) is reported by health care workers more frequently than exposure to human immunodeficiency and hepatitis B virus. The transmission rate following such an exposure is approximately 1.9%. Little is known about the attendance rate of such staff for follow-up testing following exposure to HCV. AIM: To determine whether our follow-up programme for staff exposed to hepatitis C would allow the early detection and treatment of infected staff members. METHOD: We reviewed all staff exposures to hepatitis C reported to the occupational health department of a London teaching hospital over a 8-year period. RESULTS: Of 105 exposures, 21% of staff attended for early (6 or 12 weeks) and late (26 weeks) post-exposure follow-up. Thirty-seven per cent attended early follow-up only and 1% attended late having not attended early follow-up. Forty per cent did not attend any follow-up appointments with us. CONCLUSION: With the availability of effective treatment for early HCV infection, it is vital that occupational health departments encourage staff to attend at least for early follow-up. Access to HCV-RNA testing at this early stage should allow detection and early treatment of the small proportion who seroconvert.     

Severe headache associated with occupational exposure to Stoddard solvent

We report a case of recurrent headaches in a woman with a workplace exposure to airborne (misted) lubricating fluid containing Stoddard solvent. For 2 months, the employee was seen by her family physician, a neurologist and an ophthalmologist. All attempted to diagnose the cause of and treat her headaches. Despite extensive testing, no etiology was discovered. Her headaches continued despite the use of medications. The employee, suspecting an occupational connection, changed the lubricating fluid at her workstation to a non-Stoddard solvent. Within 2 days she reported the complete resolution of her headaches with no further recurrences. A thorough occupational history and literature review supported exposure to Stoddard solvent as the probable source of her headaches.     

Organophosphate toxicity and occupational exposure

The ubiquitous organophosphates present a continuing health hazard in agriculture, public health eradication programmes and as chemical warfare agents. Despite significant progress in understanding the potential mechanisms of toxicity far beyond the commonly accepted mechanism of cholinesterase inhibition in intentional exposures, the precise health effects following occupational exposures are yet to be completely defined. A much greater understanding exists of the clinical features of organophosphate poisoning. These are characterized by a triphasic response involving an initial acute cholinergic phase, an intermediate syndrome (both associated with high mortality) and a disabling but non-lethal delayed polyneuropathy. The delayed polyneuropathy may occur in the absence of the cholinergic or intermediate phases. However, progress is still required in order to improve the quantification and assessment of occupational exposures and the implementation of appropriate preventive measures. Finally, evidence-based guidelines for appropriate or optimal therapeutic interventions following poisoning are required urgently and collaborative work with colleagues in developing countries, where the occurrence of organophosphate exposures is more frequent, may provide the answers.     

Assessing occupational and environmental exposure

Exposure assessment is a poorly understood component of the science of epidemiology. The relationship between exposure to chemicals and ill-health outcomes is often calculated using crude exposure measures such as ever/never exposed or duration. When investigating subtle effects, exposures need to be characterized much more fully in terms of intensity, frequency, duration and route. While occupational exposures tend to be much greater than those experienced from the wider environment there is a need to remember that, for many chemicals, exposure can occur occupationally, environmentally and through consumer use of products containing the material of interest. Inhalation exposure has generally been the traditional focus for most epidemiological investigations but there is now growing awareness of the importance of the dermal and ingested routes of contact and internalization. Quantification of the exposure also needs to be related to a biological mechanism of action and exposure metrics need to be selected accordingly. Occupational exposures can generally be measured using simple well-validated techniques. Environmental exposures require much more sensitive instruments and are more difficult to assess. Exposure modelling, particularly for the environmental fate of chemicals has undergone many recent developments and Monte Carlo techniques can be used to characterize model uncertainty and variability. This approach to exposure assessment can now be used in the setting of the wider environment and will enable a far better understanding of the relationship between exposure and disease.     

Cardiovascular effects of occupational exposure to carbon disulphide

The objective of this study was to investigate the effect of occupational exposure to carbon disulphide (CS2) on the total cholesterol, blood pressure and prevalence of coronary heart disease (CHD). A cross-sectional study involving 252 viscose rayon workers and 252 age and sex matched controls was carried out. Depending on the job and specific work place, the CS2 concentrations were between 10 and 64 mg/m3. A cumulative exposure index (CS2 index) was calculated for each worker by multiplying the number of years he had held a particular job with the CS2 concentrations in that job. CHD prevalence among the exposed was higher than among the controls; the difference reaching significance only for highly exposed workers. Cholesterol levels were significantly higher in both highly and moderately exposed groups. In conclusion, the results demonstrated that occupational exposure to CS2 increases total cholesterol and the risk for CHD. While the risk for CHD is increased in workers exposed to high CS2 concentration for many years (CS2 index > or = 300), even the relatively modest exposure (CS2 < 300) may increase the serum cholesterol.     

Dermal exposure assessment in occupational medicine

The importance of dermal exposure has increased during the last few years, mainly because of the reduction of respiratory exposure to toxicants. Pesticides, aromatic amines and polycyclic aromatic hydrocarbons are considered to be the chemicals at highest dermal risk. In the occupational exposure limit lists of the American Conference of Governmental Industrial Hygienists (ACGIH) and of many countries, compounds that can be absorbed through the skin are identified by a skin notation. However, a generally accepted criterion for assigning skin notation does not exist. The recent attempts to develop health-based dermal occupational exposure limits (DOELs) have not been accepted, thus in practice their use has remained limited. To predict the systemic risk associated with dermal exposure and to enable agencies to set safety standards, penetration data are needed. Moreover, there is a need for a practical risk assessment model, particularly for small and medium-sized enterprises.     

Renal cell carcinoma and occupational exposure to chemicals in Canada

This study assesses the effect of occupational exposure to specific chemicals on the risk of renal cell carcinoma in Canada. Mailed questionnaires were used to obtain data on 1279 (691 male and 588 female) newly diagnosed, histologically confirmed renal cell carcinoma cases and 5370 population controls in eight Canadian provinces, between 1994 and 1997. Data were collected on socio-economic status, smoking habit, alcohol use, diet, residential and occupational histories, and years of exposure to any of 17 chemicals. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived using unconditional logistic regression. The study found an increased risk of renal cell carcinoma in males only, which was associated with occupational exposure to benzene; benzidine; coal tar, soot, pitch, creosote or asphalt; herbicides; mineral, cutting or lubricating oil; mustard gas; pesticides; and vinyl chloride. Compared with no exposure to the specific chemical, the adjusted ORs were 1.8 (95% CI = 1.2-2.6), 2.1 (1.3-3.6), 1.4 (1.1-1.8), 1.6 (1.3-2.0), 1.3 (1.1-1.7), 4.6 (1.7-12.5), 1.8 (1.4-2.3) and 2.0 (1.2-3.3), respectively; an elevated risk was also associated with exposure to cadmium salts and isopropyl oil. The risk of renal cell carcinoma increased with duration of exposure to benzene, benzidine, cadmium, herbicides and vinyl chloride. Very few females were exposed to specific chemicals in this study; further research is needed to clarify the association between occupational exposure to chemicals and renal cell carcinoma in females.     

Anaphylaxis and allergic contact urticaria from occupational airborne exposure to HBTU

We describe a case of anaphylaxis and allergic contact urticaria from occupational airborne exposure to HBTU (o-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate), which is a chemical used widely for solid and solution-phase peptide synthesis. Previously, the use of this chemical has been associated with occupational asthma, allergic contact urticaria and allergic contact dermatitis in individual cases, but not with anaphylaxis. Our diagnoses were based on the clinical symptoms, positive skin prick test (SPT) and positive skin provocation test to HBTU. The positive SPT indicates that the anaphylaxis reaction was IgE-mediated. We recommend that in the handling of HBTU, appropriate safety measures should be compulsory, and if work-related symptoms develop, the possibility of anaphylaxis should be considered in advising on appropriate work tasks.     

The influence of occupational exposure on male reproductive function

Recently, many studies have found a decrease in semen quality which has increased the focus on male reproductive health. Occupational hazards are by far the best documented in reproductive epidemiological research. Generally, occupational exposures have been divided into physical exposures (heat and radiation), chemical exposures (solvents and pesticides), psychological exposures (distress), exposure to metals and welding. The recent and/or most important epidemiological studies exploring the effect of occupational exposures on semen quality and fecundity, the ability to conceive, are reviewed. The evidence for an adverse effect on male reproduction of several occupational and environmental exposures and toxicants, such as heat, ionizing radiation, inorganic lead, dibromochloropropane, ethylene dibromide, some ethylene glycol ethers, carbon disulfide and welding operations, is strongly supported in well-designed epidemiological studies. For other agents, the association is only suspected or suggested and needs further evaluation before conclusions can be drawn. It is also important to bear in mind that many workers in the non-Western world still are exposed to substances that are banned in the Western world, sometimes in high concentrations.     

Peer support in an occupational setting preventing LBP-related sick leave

Background Low back pain (LBP) is among the most frequent causesof sickness absence in Norway, and it is thought that it couldbe reduced by 30–50% if present day knowledge was implementedin the workplace. Evidence-based interventions in occupationalsettings to prevent sickness absence are still lacking. Aim To evaluate whether peer support would be able to modifygeneral beliefs about LBP, pain experiences, health care utilizationand sickness absence due to back pain. Methods In addition to a media campaign in two Norwegian countiesin 2002–05, aiming at improving beliefs about LBP in thegeneral public, the ‘Active Back’ project traineda peer adviser in six participating workplaces. The task ofthis peer adviser was to provide information aimed at reducingfear of the pain, supportive advice and arrange for modificationsof workloads, etc., for a limited period of time. Results The prevalence of back pain remained constant throughoutthe study period, but self-reported intensity of LBP decreasedat the end. There was a small decline in use of health careprofessionals and significant improvements in beliefs, in linewith the messages of the campaign. Total sickness absence decreasedby 27% and the LBP-related sickness absence by 49%. Conclusion The combination of peer support and modified workloadseemed to have additional effects to the general media campaign,and resulted in decline in sickness absence and improvementsin beliefs about back pain.     

Surveillance on self-report: a trial of health and safety monitoring in occupational settings

A method for monitoring health and safety in the workplace, referred to as 'surveillance on self-report', is presented. This occupational health and safety monitoring method consists of a collection of data on certain aspects of health and safety obtained by dispensing self-administered questionnaires to employees or managers and supervisors in workplaces, and administering regular feedback on the responses. Based on the responses, a continual monitoring and improvement on certain aspects of health and safety were possible in two workplaces in New Zealand. This study has shown a methodology for the surveillance of hazard control and monitoring, injuries and illnesses, and organizational policies in occupational settings.     

Chickenpox ARDS in a health care worker following occupational exposure

A case is described of chickenpox acute respiratory distresssyndrome in an ambulance driver after the inter-hospital transferof a patient known to have chickenpox pneumonia. Following thisexposure, he neither avoided patient contact nor received varicellazoster immune globulin. He subsequently required 13 days ofventilatory support before making a full recovery. The casedescribed supports the contention that health care workers shouldbe screened by serology for immunity to chickenpox before patientcontact occurs, with subsequent vaccination of those who arenon-immune, when the vaccine becomes available.     

A meta-analysis of occupational trichloroethylene exposure and multiple myeloma or leukaemia

BACKGROUND: Trichloroethylene (TCE) has been widely used as an industrial solvent and degreasing agent. AIMS: We conducted a meta-analysis of epidemiologic studies of occupational TCE exposure and multiple myeloma (MM) or leukaemia. METHODS: We identified a total of eight cohort or case-control studies that enumerated a TCE-exposed study population and presented relative risk (RR) estimates for MM (n = 7) and/or leukaemia (n = 7). The individual studies included aerospace or aircraft workers (n = 3 studies), workers from a transformer manufacturing plant (n = 1 study) and workers from numerous occupations who, based on biomonitoring or extensive industrial hygiene exposure measurements, were likely exposed to TCE (n = 4). We used random effects models to calculate summary relative risk estimates (SRRE). In addition, we examined heterogeneity across studies and the relative influence of each individual study on the overall meta-analysis. RESULTS: No association was observed for MM (SRRE = 1.05, 95% CI: 0.80-1.38; P value for heterogeneity = 0.94) or leukaemia (SRRE = 1.11, 95% CI: 0.93-1.32; P value for heterogeneity = 0.50), based on TCE-exposed subgroup meta-analyses. Study-specific RR estimates for MM ranged between 0.57 and 1.62. RRs for leukaemia ranged between 1.05 and 1.15 in five studies, while one study reported a 2-fold increased RR and another study reported an inverse association of 0.60. All confidence intervals (CIs) for study-specific estimates included 1.0. CONCLUSIONS: The results of this meta-analysis do not support an etiologic association between occupational TCE exposure and risk of MM or leukaemia.     

Analysis of the clinical state of patients with occupational asthma following cessation of exposure to allergens

The purpose of this study was to evaluate the health state of patients with occupational asthma after cessation of occupational exposure to bakery allergens. A follow-up study of 56 subjects with occupational asthma was carried out. Subjects were examined twice: 1-6 months after removal from occupational exposure and 36 or 48 months later. Clinical state analysis both at diagnosis and re-examination was performed with the use of a questionnaire. Functional spirometric tests and skin prick tests and/or specific serum IgE were carried out during both examinations at points of time at which the subjects regarded their asthma symptoms as least severe. According to the subjective evaluation of the patients' clinical state, some improvement could be noticed 36 or 48 months after removal from work. Forced expiratory volume in one second (FEV1) and peak respiratory flow (PEF) did not change significantly. Total serum IgE concentration decreased in only two subjects, but the mean value of total IgE level did not significantly differ at the first and second examination after the cessation of occupational exposure. There was no significant difference in the number of positive skin prick tests to common and occupational allergens between the first and second examination. The majority of patients with occupational asthma reporting subjectively on their symptoms indicated an improvement in their clinical state 2-3 years after removal from occupational exposure. The intensity of skin prick tests was not reduced in the studied group. Non-specific bronchial hyper-responsiveness was not reduced in the majority of subjects with occupational asthma at least 2 years after cessation of occupational exposure.     

Clinical and electromyographic examinations of patients with tremor after chronic occupational lead exposure

Tremor is considered to be a clinical sign of patients with chronic lead exposure. However, the type of tremor and its pathophysiological mechanisms are controversial. The aim of this study was to examine the clinical and electromyographic characteristics of tremor in patients with chronic lead exposure. Twenty-three men, 27-49 years old, participated in the study. The tremor activity was detected using surface electrodes from a pair of antagonistic hand muscles. Serum lead concentrations were measured on the day of examination. Our results revealed 12 Hz postural and kinetic tremor, with characteristics of enhanced physiological tremor. Different pathophysiological mechanisms might be responsible for the enhanced physiological tremor of patients with chronic lead exposure. In conclusion, the tremor of patients with chronic lead exposure is an enhanced physiological one. It is probable that this tremor could be influenced by beta-blockers, known to influence the enhanced physiological tremor in anxiety. This will be of benefit for patients disturbed by persistent tremor.     

Assessment of colour vision impairment in male workers exposed to toluene generally above occupational exposure limits

We investigated colour vision impairment in 45 male workersoccupationally exposed to toluene (mean value of toluene concentrationin ambient air=119.96 ppm) and in 53 controls. Colour visionwas evaluated by Lanthony-D-15 desaturated test and expressedas Age and Alcohol Intake Adjusted Colour Confusion Score (AACDS)or types of dyschromatopsia. Exposure was evaluated by measurementof toluene concentration in ambient air and blood, and hippuricacid and orthocresol determined in urine after the workshift.A statistically significant higher AACDS value was establishedin the exposed subjects compared to the controls (p<0.0001).There was no significant difference between AACDS values onWednesday morning compared to Monday morning. In the exposedgroup AACDS significantly correlated with the concentrationof toluene in ambient air, concentration of toluene in bloodand the concentration of hippuric acid in urine after the workshift(all p<0.0001). Dyschromatopsias were detected in both groups,although no significant difference between groups was established.In the exposed group, concentration of toluene in ambient air,alcohol intake and age explained 35.1%, concentration of toluenein blood, age and alcohol intake explained 19.9%, and concentrationof hippuric acid in urine and age explained 19.2% of the variationin type III dyschromatopsia. Concentration of toluene in ambientair and age explained 28.3% of the variation in total dyschromatopsia,and concentration of hippuric acid and age explained 13.8%.In the control group, age and alcohol intake explained 19.6%of the variation in type III dyschromatopsia. In exposed workersa significant difference was found in the AACDS value comparedto controls. However, no significant difference was found inthe prevalence of colour vision loss in the yellow-blue and/orred-green axis. Based on the results of this study the authorsconclude that the effect of toluene on colour vision can bechronic and that the possible reparation period in colour visionimpairment is longer than 64 hours.     

Work activity analysis of Finnish occupational health professionals

BACKGROUND: Some Finnish studies have dealt with how occupational health nurses divide their working hours but other occupational health professionals have not been evaluated. AIMS: This study describes how occupational health professionals allocate their working hours between main tasks. METHODS: Questionnaires were sent to 250 occupational health professionals, of whom 176 (70%) returned the completed forms. The data were analysed by using frequencies, means and one-way analysis of variance test. RESULTS: Employee-oriented tasks accounted for roughly 50% of working hours from all occupational health professionals. The remaining working hours were shared between workplace visits, co-operation with partners, other occupational health care responsibilities and tasks in other health care fields, especially in the health care centres. These working hours varied greatly between the different occupational health professional groups. All units employed full-time occupational health nurses, but the services of physicians, physiotherapists and psychologists were usually provided part-time or even restricted to a few hours each week because these services were difficult to obtain. Occupational health nurses working in the municipal health care centres spent more time on workplace visits than other nurses. Employee-oriented tasks were emphasized more in physicians', physiotherapists' and psychologists' work, especially in private medical health care units and in the jointly owned health care units. CONCLUSIONS: The amount of time occupational health professionals are able to spend on workplace activities appears to be determined by the type of their employer.     

Occupational exposure to ionizing and non-ionizing radiation and risk of glioma

BACKGROUND: Although the aetiology of glioma is poorly understood, the higher incidence in males has long suggested an occupational cause. AIM: To investigate possible associations between occupational exposure to ionizing, ultraviolet (UV), radiofrequency (RF) and extremely low frequency (ELF) radiation and adult glioma risk. METHODS: Case-control study using histologically confirmed cases of glioma first diagnosed between 1987 and 1991 in Melbourne, Australia, matched by age, sex and postcode of residence. A detailed occupational history was obtained for each subject. Exposure to radiation was assessed using a Finnish job exposure matrix (FINJEM) for all the radiation types as well as self-reports and expert hygienist review for RF and ionizing radiation. For ELF and UV, gender-specific FINJEM analysis was performed. RESULTS: The study population consisted of 416 cases of glioma and 422 controls. The risk estimates given by FINJEM for ELF, RF and ionizing radiation were close to or below unity. Gender-specific analysis for UV showed odds ratios of 1.60 [95% confidence interval (CI) 0.95-2.69] and 0.54 (95% CI 0.27-1.07) for the highest exposed group of men and women, respectively (corresponding P value for trend was 0.03 and 0.04). CONCLUSIONS: We did not find evidence of an association between glioma and occupational exposure to ELF, RF and ionizing radiation. UV radiation was associated with increased glioma risk for men but this result could have been confounded by other predominantly male occupational and lifestyle exposures associated with high UV. Further investigation of UV radiation and glioma risk is suggested.