Chronic bronchitis, work related respiratory symptoms, and pulmonary function in welders in New Zealand

OBJECTIVES: A cross sectional study of respiratory symptoms and lung function in welders was performed at eight New Zealand welding sites: 62 current welders and 75 non-welders participated. METHODS: A questionnaire was administered to record demographic data, smoking habit, and current respiratory symptoms. Current and previous welding exposures were recorded to calculate a total lifetime welding fume exposure index. Forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) were measured before the start of the shift. RESULTS: There were no significant differences in ethnicity, smoking habits, or years of work experience between welders and non-welders. Symptoms of chronic bronchitis were more common in current welders (11.3%) than in non-welders (5.0%). Of those workers with a cumulative exposure index to welding fume > or = 10 years, 16.7% reported symptoms of chronic bronchitis compared with 4.7% of those with a cumulative exposure index < 4 years (odds ratio (OR) 4.1, 95% confidence interval (95% CI) 0.90 to 17.6). Workers with chronic bronchitis had significantly lower measures of baseline PEF (p = 0.008) and FEV/FVC ratio (p = 0.001) than workers without chronic bronchitis. Multivariate analysis showed that current smoking (OR 9.3, 1.0 to 86.9) and total exposure index to welding fumes > 10 years (OR 9.5, 1.3 to 71.9) were independent risk factors for chronic bronchitis. The report of any work related respiratory symptom was more prevalent in welders (30.7%) than non-welders (15.0%) and workers with these symptoms had significantly lower FEV, (p = 0.004) and FVC (p = 0.04) values. Multivariate analysis identified a high proportion of time spent welding in confined spaces as the main risk factor for reporting these symptoms (OR 2.8, 1.0 to 8.3). CONCLUSION: This study has documented a high prevalence of symptoms of chronic bronchitis and other work related respiratory symptoms in current welders. Also, workers with chronic bronchitis had reduced PEF and FEV/FVC compared with those without chronic bronchitis. These symptoms related both to cigarette smoking and a measure of lifetime exposure to welding fume.

 

     

Respiratory health of plywood workers occupationally exposed to formaldehyde

This study was undertaken to enlarge our understanding of the adverse health effects of formaldehyde exposure in the workplace and community environment. The respiratory health status of 186 male plywood workers was evaluated by spirometric tests, respiratory questionnaires, and chest x-rays. Area concentrations of formaldehyde were measured in the work environment and found to range from 0.28 to 3.48 ppm. The average personal exposure was to 1.13 ppm of formaldehyde. Exposure to formaldehyde was associated with decrements in the baseline spirometric values, i.e., forced expiratory volume in 1 sec (FEV1.0), forced expiratory volume/forced vital capacity (FEV/FVC), and FEF25%-75%, and with several respiratory symptoms and diseases, including cough, phlegm, asthma, chronic bronchitis, and chest colds. The results of the study support the hypothesis that chronic exposure to formaldehyde induces symptoms and signs of chronic obstructive lung disease.     

Respiratory health of workers exposed to metal dusts and foundry fumes in a copper refinery.

OBJECTIVES--To assess airflow limitation in workers exposed long term to metal dust, the prevalence of pleural plaques in those workers exposed in the past to asbestos, the influence of pleural plaques on lung function, and the possible association with airway disease caused by asbestos. METHODS--A cross sectional and longitudinal (seven year) survey of 494 long term (mean (SEM) 21(1) years) workers in a copper refinery was carried out from medical questionnaires, chest radiographs, and forced spirometry. RESULTS--The prevalence of lifetime non-smokers was 19%, current smokers 39%, and ex-smokers 42%. The prevalence of chronic obstructive pulmonary diseases (COPD) (forced expiratory volume in one second (FEV1) < 80% predicted) was 5%, small airway dysfunction (SAD) (maximal mid-expiratory flow (MMEF) < 60% predicted) was 7%, and this did not differ from the control population. The COPD and SAD were associated with cumulative smoking index but not with the cumulative work years at the plant or with any type of work at the plant. The mean (SEM) reduction of FEV1 was 20(7) ml in non-smokers, 26(4) ml in smokers, and 26(5) ml in ex-smokers (P > 0.05). In the smokers and ex-smokers with COPD, the loss of FEV1 was 53(10) (P < 0.02). The prevalence of pleural plaques was 11% (P < 0.0001); pleural plaques were found in older workers with known exposure to asbestos. The pleural plaques were circumscribed and associated with a non-significant 196 ml reduction in forced vital capacity (FVC) and non-significant reduction of FVC over time. The pleural plaques were not associated with COPD or SAD. The cumulative smoking index obtained by a technician did not differ from that by a chest physician. CONCLUSIONS--Despite exposures to asbestos that produced pleural plaques and exposures to metal dusts and foundry fumes the long term workers of this plant did not have excessive prevalence of COPD or SAD. The data suggest that low level long term exposure to metal dusts, gases, and foundry fumes do not necessarily cause respiratory dysfunction, circumscribed pleural plaques with low grades of width and extent do not reduce FVC significantly, and exposure to asbestos dust that produced pleural plaques does not necessarily produce airway dysfunction.     

Lung function among asbestos cement factory workers: cross-sectional and longitudinal study

Ventilatory capacity tests and standardized respiratory questionnaires were used in 1973 and in 1980 to measure the effect of mixed dust exposure in the asbestos cement industry on respiratory symptoms and lung function in 65 exposed workers and 30 controls (exposed to polyvinyl chloride but not to asbestos). Workers exposed to asbestos had 1) a higher prevalence of breathlessness and chest pain, and a higher incidence of breathlessness; 2) lower 1980 values of forced vital capacity (FVC) (0.27-0.83 liters) and forced expiratory volume in 1 sec (FEV1) (0.23-0.62 liters); and 3) a faster decline (nearly 40 ml/year) in FVC and FEV1 between 1973 and 1980. The FVC annual decrease was 52.5 ml in the subjects with more than 15 years since first asbestos exposure, whereas it was 24.3 ml in those with less than 15 years, suggesting a faster decline after 15 years of exposure. The effect of asbestos exposure and smoking habits was less than additive as regards pulmonary function.     

Respiratory symptoms and lung function in jute processing workers: a primary investigation

This paper presents the results of an investigation of respiratory symptoms and lung function of 404 workers who had been exposed to jute dust in a jute mill. Measurement of total dust concentration and analysis of dust composition were also conducted. Most workers in the jute mill were exposed to jute dusts containing less than 5% silica, whereas a few workers were exposed to dusts containing approximately 10-15% silica. Male smokers and nonsmokers in the dust-exposed group had a higher prevalence of cough and chest tightness compared with those in the control group. Among dust-exposed workers, female nonsmokers had a significantly higher prevalence of cough, chronic bronchitis, chest tightness, and dyspnea than those in the control group. Lung function tests showed that dust-exposed workers had a greater incidence of abnormal lung function than did control workers, as measured by percentage of predicted forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1.0), and FEV1.0/FVC. Dust exposure was the main cause of respiratory symptoms and abnormal values of FEV1.0, but both cigarette smoking and dust exposure contributed to the abnormal values reported for FEV1.0.     

The health effects of automobile exhaust. VI. Relationship of respiratory symptoms and pulmonary function in tunnel and turnpike workers

To examine the effect of automobile exhaust on respiratory symptoms and pulmonary function, the authors studied 175 tunnel and turnpike workers employed by the Massachusetts Turnpike Authority on two occasions 3 yr apart beginning in 1972. A standard respiratory symptom and illness questionnaire was administered, spirometry was performed, and proximal hair lead and blood lead content were measured as biologic indices of automobile exhaust exposure. One hundred nine (63%) workers were current cigarette smokers, 41 (23%) were exsmokers, and 24 (14%) had never smoked. Smoking was strongly related to respiratory symptoms of cough (P less than .001) and phlegm production (P less than .001), but not to wheezing (P = .41), breathlessness (P = .14), bronchial asthma (P = .13), or frequent chest colds (P = .14). When workers were stratified by smoking status, no effect could be seen between high automobile exhaust exposure as measured by a variety of parameters and all of the above respiratory symptoms and illnesses. The level of pulmonary function [forced expiratory volume in 1 sec (FEV1.0) and forced vital capacity (FVC)] was not related to past or current exhaust exposure in a cross-sectional analysis when we controlled for age, height, and cigarette consumption. In a prospective analysis of 84 of these workers, the observed changes in FEV1.0 and FVC over 3 yr were unrelated to exhaust exposure after controlling for age, height, cigarette consumption, and initial level of pulmonary function.     

Radiographic (ILO) readings predict arterial oxygen desaturation during exercise in subjects with asbestosis

Background: Exercise impairment is common in subjects with asbestosis. Arterial oxygen desaturation during exercise is an important contributor to exercise limitation. The International Labour Office (ILO) classification of plain chest radiographs correlates with resting pulmonary function, but its value in predicting abnormal ventilatory responses to exercise, including desaturation, has not been explored. Aims: To determine in subjects with asbestosis (1) if radiographic profusion scores and the extent of small irregular shadows on plain chest radiographs correlate with resting lung function and abnormal ventilatory responses to exercise; and (2) if radiographic scores add value to resting lung function tests in predicting abnormal ventilatory responses to exercise. Methods: Thirty eight male subjects with asbestosis were included. Plain chest radiographs were read according to the ILO classification independently by three observers. All subjects underwent assessment of lung function and an incremental exercise test. Results: Profusion scores and number of affected zones correlated significantly with the percentage predicted values of single breath diffusing capacity (DLCO), forced vital capacity (FVC), and total lung capacity (TLC). Arterial oxygen desaturation occurred in 29% of the subjects. The severity of desaturation correlated significantly with profusion and the number of affected zones. The combined use of number of affected zones, FEV₁/FVC ratio and DLCO predicted desaturation during exercise with an explained variance of 41%. VO₂max was significantly related only to DLCO but was not predicted by the ILO score. Conclusion: Arterial oxygen desaturation correlated with the profusion and extent of parenchymal abnormality on chest radiographs. The addition of morphological indices to physiological measurements is valuable for predicting oxygen desaturation during exercise but not for VO₂max. Refinement of the radiographic scoring system and the addition of more sophisticated imaging techniques may further improve the predictive power.     

Respiratory abnormalities among male foundry workers in central Taiwan

The objectives of this study were to determine the relationship between exposure levels and respiratory abnormalities, to measure FVC and FEV1(1) changes per year based on work duties and to investigate the prevalence of and factors related to pneumoconiosis. A total of 583 male workers from 50 iron foundries in central Taiwan were investigated. First, workers' respiratory symptoms were categorized using a modified American Thoracic Society (ATS) questionnaire and then were verified by physician's examination. Next, pulmonary function tests were performed including: forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced expiratory flow rate. A chest radiograph was used to diagnose pneumoconiosis according to ILO criteria. Furnace workers were found to have the highest prevalence of chronic phlegm, thoracic disorders and chronic bronchitis. In general, smokers had a higher prevalence of respiratory symptoms as compared with non-smokers. Pulmonary function abnormalities and pneumoconiosis were closely linked to smoking and work duration. After adjusting for age, height and smoking there was a significant decrease based on work duration in FVC and FEV1 for furnace and moulding workers compared with after-processing and administrative workers. The overall prevalence of pneumoconiosis was 8.8%, highest among furnace (16.3%) and after-processing workers (11.4%) and lowest among administrative workers (2.5%). Using multiple logistic regression, the risk of developing pneumoconiosis (as compared with the administrative workers) for furnace workers was highest (8.98 times greater risk), followed by after-processing workers (6.77 times greater risk) and moulding workers (5.41 times greater risk). Prolonged exposure to free silica, and smoking habits, can result in respiratory abnormalities among foundry workers.     

Silicosis and lung function decrements among female ceramic workers in Italy

It is well known that male ceramic workers have elevated risks of chronic silicosis. The objective of this study was to assess whether female ceramic workers also have an increased risk of silicosis and whether these women have decreased lung function related to silica exposure. Ceramic workers from Civitacastellana, Italy, were enrolled in health surveillance during the 1970s. A total of 642 women were under surveillance; a respiratory monitoring program was conducted from 1974 to 1987, with follow-up through 1991 that included annual chest radiography and measurement of lung function. Radiography findings were defined as silicosis if the chest films were > or =1/0 with small, rounded opacities. Multiple linear regression models for repeated measures (generalized estimating equations) were run to evaluate associations of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV(1)) with years of exposure and radiograph opacities. Nine cases of silicosis were identified on the basis of radiographic evidence. Silicosis risk was not associated with smoking but was related to employment before 1970 and demonstrated a dose-response gradient for years of exposure. FVC and FEV(1) both showed significant (p < 0.05) associations with duration of exposure and with positive radiography findings. The results for female ceramic workers are consistent with those for male employees regarding exposure to fibrogenic dusts.     

Respiratory morbidity in wollastonite workers

Medical and environmental surveys were conducted at a wollastonite mine and mill in 1976 and in 1982. Health testing included chest radiography, spirometry, and a questionnaire. Workers at a nearby electronics plant were also examined in 1982 for a comparison of lung function and respiratory symptoms. Both wollastonite and control workers showed significant smoking effects for chronic respiratory symptoms, but differences between the groups were not detected. Pneumoconiosis was found in 3% (3/108) of the wollastonite workers in 1982, but none showed a significant progression from their 1976 radiographs. The lung function tests of the 108 wollastonite workers examined in 1982 showed dust related changes in FEV1, FEV1/FVC ratio, and peak flow rate which were independent of age, height, and smoking habit (p less than 0.01). For non-smokers alone, only the FEV1/FVC ratio declined significantly with dust-years of exposure (p less than 0.01). The comparison of lung function in 1982 between a high dust exposed subgroup of wollastonite workers and the control population showed a significantly lower FEV1/FVC ratio and peak flow rate in the study group (p less than 0.05). Analysis of 1976-82 changes in pulmonary function showed that wollastonite workers with higher dust exposure had a significantly greater decline in peak flow over the period than workers with lower exposures (p less than 0.01). These data suggest that long term cumulative exposure to wollastonite may impair ventilatory capacity as reflected by changes in the FEV1/FVC ratio and peak flow rate.     

Beryllium exposure and pulmonary function: a cross sectional study of beryllium workers

A cross sectional study of 297 white male workers employed in a large beryllium plant was conducted to test the hypothesis that long term exposure to beryllium is associated with decrements in pulmonary function. Spirometric measurement of pulmonary function, chest radiographs, and arterial blood gas measurements were collected. After controlling for age, height, and smoking in multivariate regression models, decrements in FVC and FEV1 were found to be associated with cumulative exposure to beryllium in the period up until 20 years before the health survey. These decrements were observed in workers who had no radiographic abnormalities. The alveolar-arterial oxygen difference was associated with cumulative exposure in the 10 years immediately before survey, after controlling for age and smoking. These findings suggest that beryllium may have both short and long term pulmonary effects that are distinct from the classic forms of acute and chronic beryllium disease.     

Respiratory morbidity in wollastonite workers.

Medical and environmental surveys were conducted at a wollastonite mine and mill in 1976 and in 1982. Health testing included chest radiography, spirometry, and a questionnaire. Workers at a nearby electronics plant were also examined in 1982 for a comparison of lung function and respiratory symptoms. Both wollastonite and control workers showed significant smoking effects for chronic respiratory symptoms, but differences between the groups were not detected. Pneumoconiosis was found in 3% (3/108) of the wollastonite workers in 1982, but none showed a significant progression from their 1976 radiographs. The lung function tests of the 108 wollastonite workers examined in 1982 showed dust related changes in FEV1, FEV1/FVC ratio, and peak flow rate which were independent of age, height, and smoking habit (p less than 0.01). For non-smokers alone, only the FEV1/FVC ratio declined significantly with dust-years of exposure (p less than 0.01). The comparison of lung function in 1982 between a high dust exposed subgroup of wollastonite workers and the control population showed a significantly lower FEV1/FVC ratio and peak flow rate in the study group (p less than 0.05). Analysis of 1976-82 changes in pulmonary function showed that wollastonite workers with higher dust exposure had a significantly greater decline in peak flow over the period than workers with lower exposures (p less than 0.01). These data suggest that long term cumulative exposure to wollastonite may impair ventilatory capacity as reflected by changes in the FEV1/FVC ratio and peak flow rate.     

Beryllium exposure and pulmonary function: a cross sectional study of beryllium workers.

A cross sectional study of 297 white male workers employed in a large beryllium plant was conducted to test the hypothesis that long term exposure to beryllium is associated with decrements in pulmonary function. Spirometric measurement of pulmonary function, chest radiographs, and arterial blood gas measurements were collected. After controlling for age, height, and smoking in multivariate regression models, decrements in FVC and FEV1 were found to be associated with cumulative exposure to beryllium in the period up until 20 years before the health survey. These decrements were observed in workers who had no radiographic abnormalities. The alveolar-arterial oxygen difference was associated with cumulative exposure in the 10 years immediately before survey, after controlling for age and smoking. These findings suggest that beryllium may have both short and long term pulmonary effects that are distinct from the classic forms of acute and chronic beryllium disease.     

Respiratory impairment in Brazilian foundry workers exposed to sand

OBJECTIVE: Foundries date back to the 16th century in Brazil and still constitute a strong economic activity today. Workers are at risk of respiratory diseases due to various exposures such as polycyclic aromatic hydrocarbons, pyrolysis degradation products, mineral dust, organic dust, resin, and isocyanates. We evaluate respiratory morbidity among workers in foundries using sand. METHODS: Six foundries with sand molding operations were selected. Length of exposure in years was utilized as a surrogate for exposure. The medical evaluation consisted of a respiratory symptoms questionnaire, occupational history, spirometry, and chest X-rays. Additionally, workers exposed to resins and a control group underwent bronchial provocation tests. RESULTS: A sample of 598 male workers with a mean age of 36.5 years (SD = 10.0) was analyzed. The mean length of exposure was 10.1 years (SD = 7.4). The overall prevalence of pneumoconiosis was 4.5%. Chronic bronchitis (CB) and X-ray profusion were significantly related to the quartiles of length of exposure (trend tests: P = 0.0055 and P < 0.001, respectively). There was a significant risk of having an abnormal FVC and FEV(1) with the presence of pneumoconiosis (OR = 4.63 CI 1.40-13-23, OR 3.34 CI 1.03-9.26, respectively). Workers exposed to resins compared with controls showed no differences in relation to spirometry, respiratory symptoms and bronchial reactivity. CONCLUSIONS: There were significant associations between length of exposure CB and prevalence of profusion 1/0 or above. There was also a significant association for pneumoconiosis versus and abnormal FVC and FEV(1). Foundry workers currently exposed to resins did not show an excess of respiratory symptoms, abnormal spirometry or increased bronchial reactivity.     

Analyses of the 1990 chest health survey of china clay workers.

During 1990 all present and retired china clay workers in the United Kingdom were invited to take part in a chest health survey. A total of 4401 china clay workers participated representing over 70% of current employees and 17% of pensioners. The survey consisted of a chest x ray film, lung function measurements, and a questionnaire on respiratory symptoms and smoking habits. The chest x ray films were read by three readers to the International Labour Office (ILO) 1980 classification. Full details of occupational history for each participant were available and for each employee an estimate of total exposure to china clay dust was derived from representative dust concentrations for each location and job. These were based on measured dust concentrations after 1978 and on estimates before 1978. Analyses of the data were carried out to investigate the relations between exposure, x ray film category, lung function, and respiratory symptoms. The percentage of people with small opacities greater than major x ray film category 1 was 0.8% (lower than in previous studies). Dust concentrations have been reduced in recent years, averaging 1.7 mg m-3 for dryers in 1990 compared with 3.5 mg m-3 in 1978. The lower effect of exposure after 1971, compared with earlier exposure, was confirmed by the analyses. After 1971 the milling of dried china clay (Atritor mills) was found to be the occupation with the highest effect on x ray film category. The relation between total exposure to china clay dust and x ray film category is such that a typical non-smoker worker employed in the most dusty of current occupations may expect to reach the lower limit of category 1 after about 42 years continuous employment in that job at current exposures. Both forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were found (as in other studies) to decline with age, more rapidly for smokers than non-smokers at the rates for FVC of 0.035 l/y and 0.033 l/y, whereas for FEV1 the rates are 0.039 l/y for smokers and 0.034 l/y for non-smokers. Changes in x ray film category are also related to lung function , a change of one major category being equivalent to about six years of aging in its effect on FEV1.     

Epidemiological-environmental study of diesel bus garage workers: acute effects of NO2 and respirable particulate on the respiratory system

Personal samples of nitrogen dioxide (NO2) and respirable particulate (RP) were collected over the shift on 232 workers in four diesel bus garages. Response was assessed by an acute respiratory questionnaire and before and after shift spirometry. Measures of exposure to NO2 and RP were associated with work-related symptoms of cough; itching, burning, or watering eyes; difficult or labored breathing; chest tightness; and wheeze. The prevalence of burning eyes, headaches, difficult or labored breathing, nausea, and wheeze experienced at work were higher in the diesel bus garage workers than in a comparison population of battery workers, while the prevalence of headaches was reduced. Mean reductions in forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), peak flow, and flows at 50 and 75% of FVC were not obviously different from zero. There was no detectable association of exposure to NO2 or respirable particulate and acute reductions in pulmonary function. Workers who often had respiratory work-related symptoms generally had a slightly greater mean acute reduction in FEV1 and FEF50 than did those who did not have these symptoms, but these differences were not statistically significant.     

A 17-year epidemiological study on changes in lung function in toluene diisocyanate foam workers

OBJECTIVE: To determine whether longitudinal declines in ventilatory capacity and the occurrence of respiratory symptoms in workers manufacturing polyurethane foam were related to toluene diisocyanate (TDI) exposure. METHODS: A population of workers from 12 UK factories was studied between 1981 and 1986 [8]. A survivor cohort of 251, of whom 217 were in the 1981-1986 study, was examined again in 1997-1998. Modified British Medical Research Council respiratory questionnaires and lung function measurements were completed for each of the 251 subjects at the beginning and end of the 17-year study period. Mean TDI exposures for all jobs in which subjects were employed were assessed and related to their occupational histories. RESULTS: The annual declines in 1-second forced expiratory volume (FEV(1)) and forced vital capacity (FVC) were not related to TDI exposure, and were typical of those measured in other populations not exposed to TDI. Over the study period the cold-foam handling group ( n=26) showed an increase in breathlessness and a significant excess decline in FVC; the exposed group ( n=175) showed an increase in wheezing (mainly smokers), whilst the low-exposure group ( n=50) showed a decrease in chest illness. Smoking and an increase in body weight both caused excess declines in FEV(1). CONCLUSIONS: This study does not provide evidence that there was any TDI-related decline in FEV(1) or in FVC over a 17-year period in workers exposed to TDI at the levels prevailing in the UK factories that manufactured flexible polyurethane foam.     

Ventilatory function and personal breathing zone dust concentrations in Lancashire textile weavers

BACKGROUND: To report findings on ventilatory function and estimations of concentrations of personal breathing zone dust in Lancashire textile weavers. Weaving room dust is considered to be less harmful than that encountered in the cardroom or spinning room and weavers are generally thought to have less respiratory disability than carders or spinners. However, this occupational group has not been extensively studied. METHODS: Each person was given a respiratory symptom questionnaire (modified Medical Research Council, UK, questionnaire on respiratory diseases). Ventilatory function tests, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were performed on each person. A representative sample of workers from each occupational group underwent dust sampling in their personal breathing zone. Dust concentrations and ventilatory tests were analysed statistically with the Student's t test, Pearson's correlation coefficient, and forward step regression for relations with symptoms and environmental factors. Significance was p > or = 0.05. RESULTS: The FEV1 and FVC were reduced in workers with respiratory symptoms (non-specific chest tightness, shortness of breath, persistent cough, and wheezing) as well as in preparation room workers, current and former smokers, Asians, those working with predominantly cotton fibre (> 50% cotton) and starch size. Mean total dust concentration (pd1) in the personal breathing zone was 1.98 mg/m3. The corresponding value for total dust with large fibres lifted off the filter paper (pd2) was 1.55 mg/m3. There was a strong correlation (r = 0.94, p < 0.0001) between pd1 and pd2. Non-specific chest tightness was predicted by low dust concentrations and persistent cough by high dust concentrations. On regression analysis, impairment of ventilatory function (FEV1, FVC) was predicted by smoking, male sex, age, not working in the weaving shed, not being white, and personal dust concentrations. CONCLUSIONS: The FEV1 and FVC were impaired in smokers and those exposed to high dust concentrations in the personal breathing zone. Symptoms were inconsistently related to dust concentrations in the personal breathing zone.

 

     

Dust exposure, respiratory symptoms, and longitudinal decline of lung function in young coal miners.

OBJECTIVES: To study the role of dust exposure on incidence of respiratory symptoms and decline of lung function in young coal miners. METHODS: The loss of lung function (forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow (MEF), carbon monoxide transfer factor (TLCO)) with time and the incidence of respiratory symptoms in 909 Sardinian coal miners (followed up between 1983 and 1993 with seven separate surveys) has been compared with the past and current individual exposures to respirable mixed coal dust. Multiple linear and logistic regression models were used simultaneously controlling for age, smoking, past occupational exposures, and other relevant covariates. RESULTS: According to the relatively low dust exposures experienced during the follow up few abnormal chest x ray films were detected. In the cross sectional analysis of initial data, significant associations between individual cumulative exposure to dust, decrements in FEV1 and MEFs, and increasing prevalence of respiratory symptoms were detected after allowing for the covariates included in the model. The yearly decline of FVC, FEV1, and single breath carbon monoxide transfer factor (TLCO/VA) was still significantly related to the individual exposure to dust experienced during the follow up, even after allowing for age, smoking, initial cumulative exposure to dust, and initial level of each functional variable. In logistic models, dust exposure was a significant predictor of the onset of respiratory symptoms besides age and smoking. CONCLUSIONS: The results show that even moderate exposures to mixed coal dust, as in our study, significantly affect lung function and incidence of symptoms of underground miners. Although the frequency of chest x ray examination might be fixed at every three or four years, yearly measurements of lung function (spirometry, MEFs, and TLCO) are recommended for evaluation of the respiratory risk from the coal mine environment to assess the need for further preventive interventions.     

Respiratory function in animal food processing workers

A group of 71 men employed in animal food processing was studied to assess the prevalence of acute and chronic respiratory symptoms and the presence of lung function abnormalities. In addition, a control group of 55 unexposed men was studied for the prevalence of chronic respiratory symptoms. A significantly higher prevalence for most of the chronic respiratory symptoms was found among the exposed workers compared to the control workers. Those workers who smoked had a significantly higher prevalence of chronic cough, chronic phlegm, chronic bronchitis, and chest tightness than the smokers in the control group. For nonsmokers, the differences between exposed and control workers were significant for chronic phlegm and chest tightness. The frequency of acute symptoms associated with the work shift was high among the animal food workers. There were significantly lower measured values for FVC, FEV1, and FEF50 in the exposed group (smokers and nonsmokers) compared to predicted lung function values. In smokers, all measured parameters of ventilatory capacity were significantly less than predicted; for nonsmokers, the FVC and FEV1 were less than normal. Our data indicate that exposure to dust in the animal food industry may be associated with the development of acute and chronic respiratory symptoms and the impairment of lung function. Smoking, in this setting, appears to aggravate these changes.