A longitudinal study of pulmonary function in coal miners in Lorraine, France

A longitudinal study of pulmonary function and radiological change has been conducted on 141 nonsmoking coal miners and 256 smoking coal miners from Lorraine, France. At the time of the first examination occasioned by radiological change or shortness of breath, the men averaged between 46.6 years and 50.9 years of age, and they retired approximately 8 years after entering the study. They have been followed for average periods of about 18 years and a mean of five FEV1 observations per man were made over that period. Changes in radiological category have been documented. Average rates of decline of FVC and FEV1 were similar, and varied between -47 ml/yr in nonsmoking miners still alive, to -78 ml/yr in deceased smoking miners. These accelerated rates were similar before and after retirement from the mine.     

Persistence of respiratory symptoms in ex-underground iron ore miners

AIMS: To assess the persistence of respiratory symptoms in ex-miners after cessation of mining exposure. METHODS: Population-based cross-sectional study using a postal questionnaire comparing prevalence of symptoms between ex-miners who had stopped mining at least 1 year before the study and referents not occupationally exposed to irritants or dust. Age, smoking and a family history of asthma were considered as possible confounders in the analysis. RESULTS: A total of 206 ex-miners and 4,560 referents participated. Ex-miners had on average been working as miners for 13 years and had stopped mining 16 years before the study. Chronic productive cough and physician-diagnosed chronic bronchitis were significantly more common among ex-miners (P < 0.05 and <0.01, respectively). Furthermore, there was a trend that other respiratory symptoms were more common in ex-miners. CONCLUSION: Ex-miners had an increased risk of chronic productive cough and physician-diagnosed chronic bronchitis many years after they had stopped working as a miner.     

Respiratory symptoms and lung function in bauxite miners

Objectives: To determine whether cumulative bauxite exposure is associated with respiratory symptoms or changes in lung function in a group of bauxite miners. Methods: Current employees at three bauxite mines in Australia were invited to participate in a survey comprising: questionnaire on demographic details, respiratory symptoms, and work history; skin prick tests for four common aeroallergens; and spirometry. A task exposure matrix was constructed for bauxite exposure in all tasks in all jobs based on monitoring data. Data were examined for associations between cumulative bauxite exposure, and respiratory symptoms and lung function, by regression analyses. Results: The participation rate was 86%. Self-reported work-related respiratory symptoms were reported by relatively few subjects (1.5%–11.8%). After adjustment for age and smoking no significant differences in the prevalence of respiratory symptoms were identified between subjects, in the quartiles of cumulative bauxite exposure distribution. The forced expiratory volume in 1 s (FEV₁) of the exposed group was found to be significantly lower than that for the unexposed group. After adjustment for age, height, and smoking there were no statistically significant differences between quartiles in FEV₁, forced vital capacity (FVC) and FEV₁/FVC ratio. Conclusions: These data provide little evidence of a serious adverse effect on respiratory health associated with exposure to bauxite in an open-cut bauxite mine in present day conditions. Received: 14 August 2000 / Accepted: 12 April 2001     

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.     

Associations of symptoms related to isocyanate, ureaformol, and formophenolic exposures with respiratory symptoms and lung function in coal miners

The respiratory effects of diphenylmethane diisocyanate (MDI)-based resins and ureaformol- and formophenolic-based resins, used in coal mining, are unknown. This cross-sectional study of 354 miners evaluated respiratory health in miners with MDI-related symptoms (IS) and ureaformol/formophenolic-related symptoms (UFS). The protocol included clinical examination, chest radiograph, questionnaire on respiratory symptoms, smoking habit, job history, resin handling, and spirometry. Resin handling concerned 27.7% of the miners. IS affected 5.6%, and 1.4% also after work. UFS affected 22.6%, and 2.3% also after work. Wheezing affected 35.6%; chronic cough, expectoration, or bronchitis about 10%; dyspnea 5.4%; and asthma 2.8%. The miners with UFS had significantly more frequent chronic cough, expectoration, chronic bronchitis, dyspnea, and wheezing, whereas those with IS at and after work had markedly lower FVC, FEV1, MMEF, FEF50%, and FEF25%. These findings raise the possibility of deleterious effects of exposures to MDI and ureaformol/formophenolic resins on respiratory health and lung function in coal miners during their working life.     

Cancer of the lung in iron ore (haematite) miners

Boyd, J. T., Doll, R., Faulds, J. S., and Leiper, J.(1970).Brit. J. industr. Med.,27, 97-105. Cancer of the lung in iron ore (haematite) miners. The mortality of Cumberland iron-ore miners has been studied by examining the death certificates of 5 811 men resident in two local authority areas (Ennerdale R.D. and Whitehaven M.B.) who died between 1948 and 1967. Comparison of the iron miners' experience with (1) that of other local men and (2) the relevant national experience has provided an assessment of the suspected occupational risk of lung cancer associated with haematite mining. During the 20-year period there were 42 deaths attributed to lung cancer among iron mine employees resident in the study area: 36 of these occurred in miners working underground, which was significantly greater than that expected from local non-mining (20·6 deaths) or national (21·5 deaths) experience. In contrast to these findings, there was no evidence of any excess mortality from lung cancer among surface workers and, for iron miners as a whole, mortality from other cancers was close to the national experience. A parallel analysis of mortality among coal miners showed a deficit of deaths from lung cancer in line with other studies. The patterns of other respiratory mortality in the two local mining groups were also in line with previous experience, and confirmed the existence of a substantial silicotic hazard associated with haematite mining in Cumberland.

These findings strengthen previous necropsy evidence and indicate that West Cumberland iron-ore miners who work underground experience an occupational hazard of lung cancer. They suggest that the miners suffer a lung cancer mortality about 70% higher than `normal'. The risk may be due to radioactivity in the air of the mines (average radon concentration of 100 p Ci/litre) or to a carcinogenic effect of iron oxide.

     

Relation between dust exposure and lung function in miners and ex-miners.

A sample of men working in the British coal industry in the 1950s has been followed up and examined 22 years later. The relations between lung function and individual cumulative exposure to respirable dust have been studied in 1867 men who were still working in the industry at the time of follow up and 2192 men who had left. Levels of forced expired volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio at follow up were found to be inversely related to exposure to respirable dust after allowing for other factors, even in men without pneumoconiosis. The magnitude of this estimated effect was equivalent to a loss of 228 ml FEV1 in response to an exposure of 300 gh/m3, a moderately high exposure for this group. Ex-miners aged under 65 had worse lung function than miners on average, suggesting that ill health had encouraged some of these men to leave the industry. Whereas a more severe response to dust exposure among ex-miners under 65 was suggested, this difference could easily have arisen by chance. The presence of symptoms of chronic bronchitis was associated with reduced levels of lung function, however, and, additionally, ex-miners under 65 with chronic bronchitis showed a more severe response of the FVC to dust exposure than miners without these symptoms. Among these ex-miners with chronic bronchitis a small group of men who had taken other jobs showed a much more severe effect of dust exposure on their lung function than the average, likely in heavily exposed men to contribute importantly to disability. Men in this group who had given up smoking showed and even more severe effect of dust exposure, equivalent to a loss of 940 ml FEV1 in response to an exposure of 300 gh/m3. These results indicate that exposure to respirable dust can occasionally cause severe respiratory impairment in the absence of progressive massive fibrosis. Dust exposure was related to a parallel reduction of FEV1 and FVC, implying that the pathology of dust induced lung damage differs form that induced by smoking. This pattern of abnormality was shown by some non-smokers, whereas smokers and ex-smokers apparently severely affected by dust showed a classic obstructive pattern of abnormality with pronounced reduction of the FEV1/FVC ratio.     

Mortality due to respiratory cancers in the coke oven plants of the Lorraine coalmining industry (Houillères du Bassin de Lorraine)

The main activity of the Houillères du Bassin de Lorraine (Lorraine Collieries), employing 23,000 operatives and executives, is coalmining. The coke production is carried out by two coke oven plants with a workforce of respectively 747 and 552 workers. The coal coking process entails the emission of noxious products such as polycyclic aromatic hydrocarbons (PAH) from the ovens. The influence of occupational exposure on mortality due to respiratory cancers, and particularly to lung and upper respiratory and alimentary tracts cancer, was investigated among a cohort of 534 male workers from the two coke oven plants who had retired from work between 1963 and 1982. The job history of each subject has been precisely reconstructed by indicating the duration of exposure on the ovens, close to the ovens, and in maintenance occupations. The cohort mortality has been analysed according to the method of indirect standardisation with reference to the French male population and by a case-control study concerning the consumption of tobacco per cohort. The mortality due to lung cancer is 2.51 times higher than expected. This excess of mortality differs, but not significantly, between the two coke oven plants (standardised mortality ratio equals 3.05 and 1.75 respectively). It is not significantly higher among subjects exposed for more than five years, directly exposed on the ovens or working near the ovens or at maintenance occupations on the ovens (SMR = 2.78), than among those exposed for less than five years (SMR = 2.35) or those not exposed at all. Even taking into account the excess of mortality due to lung cancers in the Moselle district (1.6 time that of France), the excess of lung cancers does not seem to be explained by the regional factor, or by tobacco and alcohol consumption. Although no significant relation was offered between lung cancer and the duration of exposure to PAH, even when taking smoking habits into account, the carcinogenic role of occupational nuisances cannot be excluded.     

Exposure to oxides of nitrogen: respiratory symptoms and lung function in British coalminers.

Five hundred and sixty British coalminers with relatively high or relatively low exposures to oxides of nitrogen, based on measurements of concentrations of these gases at nine collieries over four years, and records of the men's places of work and colliery mining conditions over a total of eight years have been studied. Data on these men's respiratory symptoms and ventilatory capacity (FEV1), obtained as part of an epidemiological study of British coalminers, have been used to investigate possible adverse effects of exposure to oxides of nitrogen. Exposures to oxides of nitrogen were generally well below threshold limit values, though occasional peaks after shotfiring and during diesel locomotive use did exceed short term limits. No relationship was found between exposure and respiratory symptoms or decline in FEV1 nor was there any evidence of differences in symptoms of FEV1 between 44 pairs of men matched for age, dust exposure, smoking habit, coal rank, and type of work, but differing in respect of exposure to oxides of nitrogen. It has not been possible to detect any adverse effects on the health of this working population of the levels of nitrogen oxides that have occurred in British mines over the past decade. With the current levels of these gases, any long term effects on respiratory health are so small as to be undetectable in the presence of smoking and dust exposure.     

Relation between dust exposure and lung function in miners and ex-miners

A sample of men working in the British coal industry in the 1950s has been followed up and examined 22 years later. The relations between lung function and individual cumulative exposure to respirable dust have been studied in 1867 men who were still working in the industry at the time of follow up and 2192 men who had left. Levels of forced expired volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio at follow up were found to be inversely related to exposure to respirable dust after allowing for other factors, even in men without pneumoconiosis. The magnitude of this estimated effect was equivalent to a loss of 228 ml FEV1 in response to an exposure of 300 gh/m3, a moderately high exposure for this group. Ex-miners aged under 65 had worse lung function than miners on average, suggesting that ill health had encouraged some of these men to leave the industry. Whereas a more severe response to dust exposure among ex-miners under 65 was suggested, this difference could easily have arisen by chance. The presence of symptoms of chronic bronchitis was associated with reduced levels of lung function, however, and, additionally, ex-miners under 65 with chronic bronchitis showed a more severe response of the FVC to dust exposure than miners without these symptoms. Among these ex-miners with chronic bronchitis a small group of men who had taken other jobs showed a much more severe effect of dust exposure on their lung function than the average, likely in heavily exposed men to contribute importantly to disability. Men in this group who had given up smoking showed and even more severe effect of dust exposure, equivalent to a loss of 940 ml FEV1 in response to an exposure of 300 gh/m3. These results indicate that exposure to respirable dust can occasionally cause severe respiratory impairment in the absence of progressive massive fibrosis. Dust exposure was related to a parallel reduction of FEV1 and FVC, implying that the pathology of dust induced lung damage differs form that induced by smoking. This pattern of abnormality was shown by some non-smokers, whereas smokers and ex-smokers apparently severely affected by dust showed a classic obstructive pattern of abnormality with pronounced reduction of the FEV1/FVC ratio.     

Decline in the lung cancer hazard: a prospective study of the mortality of iron ore miners in Cumbria.

The mortality of 1947 Cumbrian iron ore miners has been studied over the period 1939-82 in relation to that among other groups of men in England and Wales: (a) all men, (b) men of similar social class, and (c) men living in similar types of (mainly rural) area. Significant excesses were found for deaths from tuberculosis and respiratory diseases compared with each of the reference populations. Lung cancer showed an excess over that in comparable (mainly rural) areas of England and Wales, as reported in a previous study using a proportionate method of analysis and which covered the period 1948-67 but no appreciable excess after 1967. Reasons for this decline are discussed.     

Respiratory symptoms and obstructive lung diseases in iron ore miners: Report from the obstructive lung disease in northern Sweden studies

This is a population-based study on the prevalence of respiratory symptoms assessed by a mail questionnaire. The objective was to examine if work in an iron mine increased the risk of airway symptoms or obstructive diseases. The exposed group consisted of 114 previous or current male miners. Referents, 2472 males from the province, had never been employed by the mining company or worked as miners. Age, smoking and a family history of asthma were considered as possible confounders. The miners had an increased risk for respiratory symptoms (OR=2.2, 95% CI=1.4–3.1) including recurrent wheeze (OR=2.4, 95% CI=1.5–3.9), longstanding cough (OR=1.8, 95% CI=1.0–3.2), and for physician-diagnosed chronic bronchitis (OR=2.2, 95% CI=1.0–4.5). Attacks of shortness of breath and asthma manifestations were similar between miners and referents. Higher risks in miners were found particularly among the non-smokers for physician-diagnosed chronic bronchitis (OR=9.2, 95% CI=3.0–28) and for symptoms as well. A family history of asthma was less common among miners (9.2% vs. 17%, p < 0.05). We conclude that miners in a modern underground iron mine had an increased risk of respiratory symptoms. In contrast to other studies, this increased risk was particularly found in non-smokers. A family history of asthma may be an important confounder in occupational studies of respiratory diseases.     

Mortality of Dutch coal miners in relation to pneumoconiosis, chronic obstructive pulmonary disease, and lung function.

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

Long term effects of low concentrations of noxious gases on the respiratory system: results of an epidemiological study among iron mines workers in Lorraine (France). (author's transl)

An epidemiological study of 1,178 iron-mine workers in the Lorraine basin was conducted in order to assess the long-term effects on the respiratory system of low concentrations of noxious gases produced by the machinery and explosives in use. The subjects were selected at random from 5,300 workers who were aged between 35 and 55, had been in the mines for at least five years and who were free from radiological abnormalities such as siderosis, tuberculosis, fractured ribs, etc. For each subject a standard questionnaire (E.C.S.C. bronchitis/emphysema questionnaire) was completed and a clinical examination was performed along with the following tests-vital capacity; forced expiratory volume in 1 second; residual volume; acetylcholine test; steady state CO test for calculation of total and partial transfer functions. A venous blood sample for the determination of blood CO was taken as the subject left his place of work.     

The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part II. Mortality

The vermiculite ore and concentrate of a mine and mill located near Libby, Montana was found to be contaminated with a fiber of the tremolite/acetinolite series. A study was conducted to estimate the exposure-response relationship for mortality for 575 men who had been hired prior to 1970 and employed at least 1 year at the Montana site. Individual cumulative fiber exposure (fiber-years) was calculated. Results indicated that mortality from nonmalignant respiratory disease (NMRD) and lung cancer was significantly increased compared to the U.S. white male population. For those workers more than 20 years since hire, the standard mortality rate (SMR) for lung cancer (ICDA 162-163) was 84.7, 225.1, 109.3, and 671.3 for less than 50, 50-99, 100-399, and more than 399 fiber-years respectively. Corresponding results for NMRD (ICDA 460-519) were 327.8, 283.5, 0, and 278.4. Based on a linear model for greater than 20 years since hire, the estimated percentage increase in lung cancer mortality risk was 0.6% for each fiber-year of exposure. At 5 fiber-years, the estimated percentage was 2.9% from an unrestricted (nonthreshold) linear model and 0.6% from a survival model.     

Decline in the lung cancer hazard: a prospective study of the mortality of iron ore miners in Cumbria

The mortality of 1947 Cumbrian iron ore miners has been studied over the period 1939-82 in relation to that among other groups of men in England and Wales: (a) all men, (b) men of similar social class, and (c) men living in similar types of (mainly rural) area. Significant excesses were found for deaths from tuberculosis and respiratory diseases compared with each of the reference populations. Lung cancer showed an excess over that in comparable (mainly rural) areas of England and Wales, as reported in a previous study using a proportionate method of analysis and which covered the period 1948-67 but no appreciable excess after 1967. Reasons for this decline are discussed.     

Exposure to oxides of nitrogen: respiratory symptoms and lung function in British coalminers

Five hundred and sixty British coalminers with relatively high or relatively low exposures to oxides of nitrogen, based on measurements of concentrations of these gases at nine collieries over four years, and records of the men's places of work and colliery mining conditions over a total of eight years have been studied. Data on these men's respiratory symptoms and ventilatory capacity (FEV1), obtained as part of an epidemiological study of British coalminers, have been used to investigate possible adverse effects of exposure to oxides of nitrogen. Exposures to oxides of nitrogen were generally well below threshold limit values, though occasional peaks after shotfiring and during diesel locomotive use did exceed short term limits. No relationship was found between exposure and respiratory symptoms or decline in FEV1 nor was there any evidence of differences in symptoms of FEV1 between 44 pairs of men matched for age, dust exposure, smoking habit, coal rank, and type of work, but differing in respect of exposure to oxides of nitrogen. It has not been possible to detect any adverse effects on the health of this working population of the levels of nitrogen oxides that have occurred in British mines over the past decade. With the current levels of these gases, any long term effects on respiratory health are so small as to be undetectable in the presence of smoking and dust exposure.     

Smoking habit, respiratory symptoms and lung function in young adults

Background: Smoking is the primary cause of deterioration inforced expiratory volume (FEV₁) and the development of chronicobstructive lung disease. This study assessed the independentassociation of smoking with respiratory symptoms and lung functionin young adults who took part in the European Community RespiratoryHealth Survey (ECRHS–I). Methods: Cross-sectional multi-centresurvey of a general population of young adults aged 20(44 yearsin the ECRHS(I conducted in five Spanish centres. Several groupswere created in an exclusive and descendent manner from thesubjects who completed the questionnaire in accordance withhow they had answered the questions: asthma-related symptoms;chronic bronchitis symptoms; minor respiratory symptoms; chroniccough; and no respiratory symptoms. Among a subset of the population,forced spirometry tests were performed. Linear and logisticalregression models were used to assess the relationship of smokingin the presence of symptoms and its impact on lung function,adjusted by other important variables. Results: The prevalenceof respiratory symptoms was higher among smokers. After adjustingfor geographical area, total IgE, age, sex, and FEV₁, smokingwas associated with an increased risk of chronic bronchitisand other respiratory symptoms. These risks increased with increasingnumber of cigarettes smoked per day. A deterioration of FEV₁and the FEV₁/FVC ratio was also directly associated with thenumber of cigarettes smoked per day. Conclusion: Even amongyoung adults, smoking confers a high risk of developing a numberof respiratory symptoms and the deterioration of the ventilatoryfunction.