Occupational asthma: a community based study.

The incidence and prevalence of occupational asthma has been extensively studied in industry settings and specialist clinics. However, it has been much less studied in the community. This study looked at the general practice notes of asthmatics in an attempt to assess the overall load of occupational asthma in the community. Eighty-six per cent of the patients with adult onset asthma in the practice population studied had at least one occupation recorded in their notes. Nearly a third of these (32%) were in jobs known to be significant causes of occupational asthma, yet a potential link between their occupation and symptoms had only been recorded in 18% of patients in these jobs. Overall 4% of the patients with adult onset asthma had been given a diagnosis of occupational asthma although in nearly half these cases the diagnosis had been made by a general practitioner and not a specialist.     

Occupational asthma prevention and management in industry--an example of a global programme

Isocyanates are widely used in the manufacture of polyurethane foams, plastics, coatings and adhesives, and are known to cause occupational asthma in a proportion of exposed workers. Substitution as a prevention strategy is not currently a feasible option. For this reason, health and safety professionals working together in an automotive coatings business created a proactive global programme to address the known potential effects of isocyanates on its workers. The goals of the programme are prevention, early detection and mitigation of effect of key endpoints, especially asthma and to a lesser degree dermatitis, in people who are occupationally exposed, or potentially exposed, to isocyanates and products containing isocyanates. The surveillance programme for isocyanates has several important components, which include assessment of exposure, pre-placement questionnaire and spirometry, training and education of employees, regularly administered periodic questionnaires, medical assessment for abnormal questionnaire responses, process for early reporting and investigation of symptomatic employees and incidents, group data review and management reporting. Although regional differences exist regarding availability of specialized services, we have successfully implemented this programme in parts of North America, Europe and Latin America, and are currently implementing elsewhere. These simple control measures are relatively inexpensive and can be applied in even small business settings. It is recommended that all employers who manufacture, handle or use isocyanate-containing products consider such a strategy.     

Health and employment after a diagnosis of occupational asthma: a descriptive study

The objectives of this study were to describe changes in asthmaand employment after diagnoses of occupational asthma reportedto the SWORD project. Questionnaires were sent to 312 physiciansfor all 1,940 cases of occupational asthma reported from 1989–92;1,769 (91%) were returned but information was available foronly 1,317 (68%). Of patients reported by occupational physicians,45% had recovered from asthma compared to only 14% of thosereported by chest physicians (excluding medicolegal cases),presumably because of differences in severity. Proportions withthe same employer were 49% and 48% respectively. Patients exposedfor a year or more after diagnosis recovered from asthma lessfrequently but were more often employed than those exposed forless than a year. Among those whose asthma was attributed tohigh molecular weight agents, smokers had developed asthma earlierafter exposure began than others but had the best prognosis.Asthma developed following a single high exposure in 18 cases(2%), of which 13 were to irritants and five to known sensitizers.     

Occupational asthma and rhinitis caused by 1,2-benzisothiazolin-3-one in a chemical worker

We report a case of occupational asthma and rhinitis causedby inhalation of 1,2-benzisothiazolin-3-one, an additive usedas a microbicidal in detergent production, in a 26-year-oldman employed in a chemical factory producing detergents. Thesubject's task consisted of pouring raw materials into the recipientof a machine which mixed the substances. Two months after thebeginning of this job the patient complained of rhinitis andasthma at the workplace. The specific challenge test with 1,2-benzisothiazolin-3-one,one of the raw materials to which the subject was exposed, provokedan immediate prolonged asthmatic response and nasal symptoms,whereas exposure to other agents (e.g., -amylase, alcalase orbezalkonium chloride) to which the patient was also exposedat work did not. To our knowledge this is the first case ofoccupational asthma and rhinitis caused by this compound.     

Occupational asthma after exposure to plaster casts containing methylene diphenyl diisocyanate

BACKGROUND: The case of a 34-year-old female nurse is presented. She worked in an accident and emergency department in a district general hospital, with methylene diphenyl diisocyanate (MDI)-containing synthetic plaster casts. She worked with MDI on a daily basis for 4 years. She was out of the department for 1 year and on her return developed cough, wheeze and dyspnoea within 5 min of exposure to MDI- containing synthetic casts. METHOD: A bronchial provocation test was performed and confirmed an early asthmatic response. RESULTS: There was a 39% decrease in the forced expiratory volume in 1 s 15 min after exposure, which required the administration of a bronchodilator on two occasions. The patient has subsequently avoided MDI-containing synthetic plaster casts and has experienced no further respiratory symptoms. CONCLUSION: This case illustrates that respiratory sensitization can occur as a result of exposure to MDI-containing synthetic casts and highlights the need for vigilance when health care workers are using isocyanate-containing synthetic casts.     

Algae-induced occupational asthma in a thalassotherapist

BACKGROUND: Algae powders have been increasingly used in therapeutic preparations. Their potential as inducers of occupational asthma (OA), however, remains to be demonstrated. METHODS: A 33-year-old woman developed asthma following exposure to algae powder used for thalassotherapy. She had positive patch tests to nickel and cobalt in an evaluation for intermittent skin rash. At work, she had a normal forced expiratory flow in 1 s (FEV(1)) but moderate airway hyperresponsiveness. Bronchial provocation tests (BPT) were obtained. RESULTS: On BPT, an isolated early response was observed after a 1-min inhalation of dry algae powder, with a 50% fall in FEV(1) after exposure; the control BPT with lactose powder was negative. CONCLUSIONS: We report a case of algae-powder-induced OA. Such responses could be due to a sensitization to algae proteins or metal contaminants bioabsorbed by the vegetal particles.     

Fifteen-year trends in occupational asthma: data from the Shield surveillance scheme

Background Trends of occupational asthma (OA) differ betweenregions depending on local industries, provisions for healthand safety at the workplace and the availability of a reportingscheme to help in data collection and interpretation. Aim To assess trends in OA in an industrialized part of theUK over a 15-year period. Methods Occupational and chest physicians in the West Midlandswere invited to submit details of newly diagnosed cases withOA. Data were then transferred to the regional centre for occupationallung diseases for analysis. Results A total of 1461 cases were reported to the scheme. Sixty-eightper cent were males with mean (standard deviation) age of 44(12) years. The annual incidence of OA was 42 per million ofworking population (95% CI = 37–45). OA was most frequentlyreported in welders (9%) and health care-related professions(9%) while <1% of cases were reported in farmers. Isocyanateswere the commonest offending agents responsible for 21% of reportsfollowed by metal working fluids (MWFs) (11%), adhesives (7%),chrome (7%), latex (6%) and glutaraldehyde (6%). Flour was suspectedin 5% of cases while laboratory animals only in 1%. Conclusions Our data confirm a high annual incidence of OA inthis part of the UK. MWFs are an emerging problem, while isocyanatesremain the commonest cause. Incidence remained at a fairly stablebackground level with many small and a few large epidemics superimposed.Schemes like Midland Thoracic Society's Rare Respiratory DiseaseRegistry Surveillance Scheme of Occupational Asthma could helpin identifying outbreaks by linking cases at the workplace.     

Silicosis and lung cancer: a mortality study of compensated men with silicosis in New South Wales, Australia

BACKGROUND: Lung cancer mortality has been found to be in excess in several groups with silicosis, but allowance for smoking was not always possible. We investigated the lung cancer mortality in men with silicosis in New South Wales, Australia, who were compensated, making allowance for smoking habits. METHODS: A mortality study of 1467 men with silicosis in New South Wales who were compensated was carried out comparing observed mortality with that expected from the New South Wales death rates adjusting for age and period. Their smoking habits were compared with national survey smoking rates and the expected number of lung cancer deaths adjusted for smoking. Cases were coded for occupation and industry. RESULTS: The observed mortality was higher than expected, but the only site of cancer showing a significant excess was the lung. The group with silicosis had smoked more than the national rates. After adjusting for smoking the standardized mortality ratio for lung cancer was 1.9 (95% confidence interval 1.5-2.3). Although there were differences in lung cancer mortality between industries and occupations, these differences were not statistically significant. CONCLUSIONS: The excess lung cancer death rate may not be entirely due to silica exposure because compensation may have been influenced by the presence of chronic obstructive respiratory disease and there is some evidence that the presence of this disease increases lung cancer risk independently of smoking.     

Occupational mental health: a brief history

This paper describes the development of occupational mental health in the United Kingdom. It looks at the increasing involvement of occupational health staff in this aspect of the workplace and the role played by organizational psychologists in exploring the relationship between work and mental well-being. It provides a background for the reviews of current knowledge described in the other papers in this issue of Occupational Medicine.     

Occupational eosinophilic bronchitis without asthma due to chloramine exposure

A case is discussed of eosinophilic bronchial inflammation without asthma due to chloramine T (CLT) exposure in a nurse. She reported a non-productive chronic cough on contact with CLT during workshifts. She had negative results of skin prick testing to CLT. However, sensitisation to CLT was confirmed by the presence of specific anti-chloramine IgE. Airway responsiveness to histamine was normal before and after CLT challenge. Eosinophil proportion in sputum was increased at 6 and 24 h after CLT challenge.     

Increased risk of asthma among Finnish construction workers

AIM: To determine the risk of asthma among 7891 Finnish construction workers in the Pirkanmaa Region of southern Finland. METHOD: Retrospective cohort study of hospital records of the Tampere University Hospital. A population of Pirkanmaa paper mill workers (n=2686) and the Pirkanmaa working age population (n=252,500) served as reference populations. RESULTS: There were 147 new cases of asthma among the construction workers in 1991-1995. The annual rate was 37 per 10,000 workers and the odds ratio was 2.1 [95% confidence interval (CI)=1.2-3.6] for the women and 1.8 (95% CI=1.5-2.2) for the men when compared with the general working age population. In general, the risk of asthma among the paper mill workers did not differ from the risk of asthma among the general working age population. The construction workers had an increased risk for asthma, although the number of reported cases of occupational asthma was lower for the construction workers than for the paper mill workers or for the working population. CONCLUSION: Construction work, especially dusty tasks, was associated with an elevated risk of asthma. Thus the effect of exposure to irritant agents may have a role in the development of asthma among construction workers. For the most part, these cases of asthma do not meet the criteria for occupational asthma because the specified causal agent can not be defined. The aetiologic agents and mechanisms of asthma in construction work should be clarified for preventive measures.     

Occupational dermatitis and allergic respiratory diseases in Finnish metalworking machinists

AIM: To investigate the incidences and trends of occupational skin diseases (OSDs) and allergic respiratory diseases (ARDs) in machinists working in the fabrication of metal products. METHODS: Data from the Finnish Register of Occupational Diseases during 1992-2001 were analysed. Incidence rates for skin and respiratory diseases of machinists were calculated and compared to the total working population. The patients investigated at the Finnish Institute of Occupational Health in the same period were described in detail. RESULTS: A total of 279 dermatoses and 34 ARDs were reported. Skin diseases accounted for 27% of all occupational diseases. The incidences of the skin and respiratory diseases were 1.6 and 0.2 cases per 1000 person-years, respectively. This represents a 3-fold risk for getting an OSD compared to the total working population. The number of allergic contact dermatitis (ACD) increased 3-fold during the study period. The most common causes of ACD were metalworking fluids (MWFs) and their ingredients such as formaldehyde, ethanolamines and colophony. Eighty-five per cent of ARDs were asthmas. The commonest causes of asthma were metal dusts and fumes, epoxy resins and hardeners and MWFs and their components. CONCLUSIONS: Contact dermatitis is a common occupational health problem in metalworking machinists, whereas occupational respiratory disease is rare. Only a few specific chemicals in the metalworking have thus far been identified as respiratory allergens. Specific skin tests and inhalation challenge tests with MWFs and their ingredients are recommended if an OSD or a respiratory disease is suspected.     

Maternal occupation and adverse pregnancy outcomes: a Finnish population-based study

BACKGROUND: There is accumulating evidence that the type of work and environmental exposures in the working environment may have adverse effects on foetal development. AIM: To compare the risk of low birth weight (LBW), small-for-gestational age (SGA) and pre-term delivery (PD) in broad categories of maternal occupation including farming and forestry; factory, mining and construction; office, non-manual and service work and housewives. METHODS: The study population consisted of 2568 singleton newborns of women who participated in The Finnish Prenatal Environment and Health Study after the delivery (response rate 94%). Information on maternal occupation and work during pregnancy was collected after the delivery. The health outcomes were LBW (<2500 g), SGA and PD (<37 weeks). RESULTS: In newborns of women working in factories, mining and construction, the risk of LBW (adjusted odds ratio [OR] 3.66, 95% confidence interval [CI] 1.15-11.62), SGA (adjusted OR 1.53, 95% CI 0.73-3.21), but not the risk of PD (adjusted OR 0.64, 95% CI 0.19-2.22), was higher compared with newborns of housewives. In newborns of farmers and forestry workers, the risks of PD (adjusted OR 2.38, 95% CI 1.01-5.65), LBW (adjusted OR 2.86, 95% CI 0.78-11.58) and SGA (adjusted OR 1.51, 95% CI 0.62-3.65) were all elevated. In office, non-manual and service workers, the corresponding estimates were lower (LBW: 1.62, 0.67-3.95; SGA: 1.45, 0.92-2.28; PD: 1.18, 0.69-2.01). CONCLUSIONS: There were substantial differences in the risk of adverse pregnancy outcomes between the main branches of industry.     

Glutaraldehyde-induced occupational asthma: BALF components and BALF and serum Clara cell protein (CC16) changes due to specific inhalatory provocation test

OBJECTIVES: The purpose of this study was to evaluate bronchoalveolar lavage fluid (BALF) components and Clara cell protein (CC16) concentration in serum and BALF in patients with glutaraldehyde (GA)-induced asthma, before and after a specific inhalatory provocation test (SIPT) with GA, in comparison to atopic asthmatics and healthy individuals. METHODS: Spirometry and bronchoalveolar lavage were performed before and after SIPT. The serum and BALF concentrations of CC16 and cytogram content in BALF were evaluated. RESULTS: In GA-sensitized asthmatics, the level of CC16 in BALF and serum was significantly lower at 24 h after SIPT in comparison with the values recorded prior to the experiment. There was a significant increase in the proportion of eosinophils, basophils and lymphocytes in BALF of GA-sensitized asthmatics obtained after SIPT. CONCLUSIONS: The determination of CC16 either in serum or in BALF is a non-invasive test to detect Clara cell damage.     

Occupational respiratory symptoms in New Zealand hairdressers

BACKGROUND: A study of occupational respiratory symptoms in hairdressers was carried out in 26 salons in New Zealand. METHODS: A questionnaire was administered to 100 hairdressers and 106 office and shop workers, recording respiratory symptoms, demographic data, and smoking habits. Pulmonary function was measured before each shift. RESULTS: Hairdressers had a higher prevalence of asthma symptoms, diagnosed asthma, and asthma attacks in the previous 12 months, but these differences reduced markedly when adjusted for age, gender and smoking. Hairdressers had a significantly lower pulmonary function, even after adjustment for smoking, but this difference was entirely due to differences between hairdressers and office workers and there were no such differences between hairdressers and shop workers. CONCLUSIONS: The excess symptom prevalence in hairdressers was largely due to the high smoking rates. Mean pulmonary function was lower in hairdressers but this finding requires further study.     

Occupational eye injuries: a continuing problem

Background Ocular trauma is a worldwide cause of visual morbidity,a significant proportion of which occurs in the workplace. Thisis largely preventable with the use of protective eyewear andstrict compliance. Aim To analyse the type of occupational eye injuries that occurand to document the use of eye protection in patients presentingto a UK district general hospital. Methods A pilot retrospective case note analysis of all ocularinjuries seen in one calendar month was performed. A prospectivesurvey of consecutive occupational ocular injuries presentingto this district general accident and emergency (A&E) departmentover a 2-month period was then carried out. Demographics, aetiology,eye protection usage and clinical details were recorded andanalysed. Results Of all eye patients attending this A&E, 31% (87/283)were due to occupational eye injuries. Of 55 prospectively reviewedpatients with occupational eye injuries, the majority had minorinjuries. Of the cases where eye protection was recorded, 56%(18/32) were not wearing any protection and 44% (14/32) woreeye protection at the time of injury. Conclusions Occupational eye injuries are a commonly seen ocularcomplaint in the A&E department. Provision of appropriateeyewear protection and worker education is required to minimizethe incidence of ocular injury in the workplace.     

Occupational contact dermatitis in the UK: a surveillance report from EPIDERM and OPRA

Since February 1993 the EPIDERM surveillance scheme has collected data on occupational skin disease from consultant dermatologists in the UK. Reporting by occupational physicians to the scheme began in May 1994 and was superseded in January 1996 by the Occupational Physicians Reporting Activity (OPRA). The schemes currently receive reports on incident cases from 244 dermatologists and 790 occupational physicians. An estimated total of 9937 cases of contact dermatitis reported by dermatologists was calculated from surveillance data; 8129 contact dermatitis cases were estimated from reports by occupational physicians. The annual incidence of occupational contact dermatitis from dermatologist reports was 6.4 cases per 100,000 workers and 6.5 per 100,000 from reports by occupational physicians, an overall rate of 12.9 cases per 100,000 workers. Manufacturing industries account for the greatest number of cases seen by both sets of reporting physicians, with health care employment second. Reports from dermatologists also indicate high rates of dermatitis in the personal service industries (mainly hairdressers and barbers) and in agriculture. With the exception of an increase in cases seen in nurses in both schemes, the numbers and proportions of cases of contact dermatitis within occupations have remained fairly constant over the 6-year reporting period. Agents accounting for the highest number of allergic contact dermatitis cases were rubber (23.4% of allergic cases reported by dermatologists), nickel (18.2), epoxies and other resins (15.6), aromatic amines (8.6), chromium and chromates (8.1), fragrances and cosmetics (8.0), and preservatives (7.3). Soaps (22.0% of cases), wet work (19.8), petroleum products (8.7), solvents (8.0), and cutting oils and coolants (7.8) were the most frequently cited agents in cases of irritant dermatitis. The national scope of the data, together with the parallel structure by which both dermatologists and occupational physicians report incident cases, is useful in determining the extent of skin hazards in UK industry and may help in better targeting efforts to reduce the burden of skin disease at work.     

Future advances in work-related asthma and the impact on occupational health

Work-related asthma (WRA) and WRA-like conditions refer to all situations in which asthma or asthma-like syndromes occur or worsen in the workplace. This occurs in approximately 10% of all adult-onset asthma subjects. Occupational asthma (OA) is a specific type of WRA that is 'caused' by the workplace, being mediated either by an allergic process with a latency period or by a non-allergic irritant-induced mechanism. Personal asthma can also 'worsen' at work (work-aggravated or exacerbated asthma), the reasons, mechanisms, extent and consequences of this situation being unknown. The author reviews various aspects of WRA with an emphasis on OA (about which more is known) and proposes key issues that need to be further studied, proposed and applied in at-risk workplaces in order to improve recognition, diagnosis and management of this condition. OA represents a unique situation that, unfortunately, is only very rarely provided to health-care providers: affected workers can be cured with minimal impact on quality of life. All efforts should be made to achieve this goal at an affordable socio-economic cost.