Asthma caused by occupational exposure to vanadium compounds

Four workers from a recently established vanadium pentoxide refinery in Western Australia presented with green discoloration of the tongue, upper respiratory symptoms, and asthma. Three of them were non-atopic as judged by history, prick skin test responses, and total serum IgE levels. The two with most recent exposure to vanadium compounds exhibited bronchial hyperreactivity to histamine. Vanadium compounds appear to be capable of inducing asthma in previously normal subjects. One subject continued to wheeze eight weeks after this last exposure.

Accelerated loss of FEV- in polyurethane production workers: a four-year prospective study

A four-year longitudinal study of ventilatory function in polyurethane-foam production workers exposed to toluene diisocyanate (TDI) revealed a dose-response relationship between average exposure to TDI and change in forced expiratory volume per second (FEV-1). Workers with mean exposure in excess of 0.0035 ppm showed a greater rate of decline of FEV-1 over the four-year period than that expected from aging. Factors other than TDI exposure (sex, smoking history, history of atopy) do not account for the loss. The current threshold limit value (TLV) for exposure to TDI in industry (0.02 ppm) does not protect workers from accelerated impairment of ventilatory capacity.

Pulmonary function in firefighters: a six-year follow-up in the Boston Fire Department

Tests of ventilatory capacity, objective cough, and standardized respiratory questionnaires were used in a prospective study to measure the effect of firefighting on pulmonary function in a cohort of 951 white Boston firefighters between 1970-1976. During the six years of follow-up, the mean annual decrements in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were 36 and 29 ml per year, respectively. At the end of the study in 1976, the mean FEV1 for this group was 98.3% of the level predicted for healthy nonsmoking adults, while the FVC was 97.8%. Current cigarette smoking was associated with an increased prevalence of bronchitis, a loose cough, reduced levels of FEV1 and FVC, and increased longitudinal changes in FEV1 and FVC. The longitudinal changes and current levels of FEV1 and FVC were not correlated with any index of firefighting exposure in active firefighters. Increased use of protective respiratory apparatus and previously described selection effects within the Boston Fire Department appear to be protecting this group of firefighters from long-term effects of smoke exposure as measured by these techniques.

Benign asbestos pleural effusion: diagnosis and course

We have reviewed 22 patients with benign asbestos pleural effusion seen over a 17-year period. The mean duration of exposure to asbestos was 5.5 years and the mean interval between exposure and presentation was 16.3 years. In five the effusion was asymptomatic. Fever was uncommon but in 15 of 21 patients the ESR was elevated. Leucocytosis was noted in seven of 20 patients. Autoantibodies were rarely detected. The pleural fluid was usually blood-stained and the volume aspirated was rarely larger than 500 ml. Pleural biopsies revealed established pleural fibrosis and/or inflammatory infiltration with fibrinous exudate and mesothelial and fibroblastic proliferation. A positive mantoux test was noted in eight of 12 patients but there was no other evidence of tuberculosis. The mean duration to spontaneous resolution of the effusion was 4.3 months. During a follow-up period of 28.1 years from initial exposure to asbestos (mean 22.8 years) and up to 17.2 years from initial presentation with a pleural effusion (mean 6.3 years) seven patients had a single recurrence and only one patient had multiple pleural effusions. Only three patients experienced persistent pleural pain. It was not possible to predict the likelihood of recurrence of an effusion or the persistence of pleural pain from the data at presentation. No patient subsequently developed mesothelioma or other neoplasm.

Relationship between type of simple coalworkers' pneumoconiosis and lung function. A nine-year follow-up study of subjects with small rounded opacities

One hundred and twenty-five men who were identified in 1968 as having the simple pneumoconiosis of coalworkers were re-examined nine years later when their mean age was 59.6 years. On both occasions the lung function and response to exercise were assessed. There was no evidence for progression of simple pneumoconiosis between the surveys, but 14 had developed small irregular opacities on their chest radiographs and 28 showed early changes of progressive massive fibrosis (PMF). After allowing for the effects of smoking and of exposure to coal dust, subjects with both p and r types of simple pneumoconiosis exhibited a reduced transfer factor compared with subjects having q-type opacities; subjects with r-type opacities also showed an increased pulmonary elastic recoil pressure. The presence of irregular opacities, independent of rounded opacities, was associated with a low transfer factor and decreased slope of phase III of the single breath oxygen test. Subjects who developed PMF between 1968 and 1978 had p or r opacities more often than q opacities: these subjects had an increase pulmonary elastic recoil pressure. The development of PMF was also associated with physiological evidence of airways obstruction. The changes in subjects with r opacities are consistent with the presence of space occupying lesions that may progress to PMF. Subjects with p opacities have physiological evidence of emphysema as do some subjects with established PMF. Irregular opacities may reflect the presence of both emphysema and diffuse fibrosis. There is need for more morbid anatomical evidence on the underlying pathology.

Pulmonary disease from occupational exposure to an artificial aluminium silicate used for cat litter

All available workers engaged in bagging an artificial crystalline aluminium silicate--the kiln-dried residue from the calcining and water extraction of alunite (a hydrated sulphate of aluminium and potassium) that is currently classified as a nuisance dust--were studied after a complaint of respiratory and systemic symptoms, including arthritis, by an employee of the factory, who showed physiological and radiographic evidence of diffuse pulmonary fibrosis and in whom lung biopsy showed diffuse fibrosis with granulomas. Inhalation challenge produced a transient decrease in transfer factor and transfer factor standardised for alveolar volume. Twenty-five subjects were known to have been exposed at some time to the dust of alunite-residue. Of the 17 who could be contacted, all agreed to attend for respiratory questionnaire and occupational history, pulmonary function testing (spirometry, lung volumes, gas transfer), and posteroanterior chest radiograph. Six subjects considered that occupational exposure to the dust was responsible for respiratory symptoms. Three subjects had abnormality of the chest radiograph consistent with pulmonary fibrosis. The mean percentage of predicted transfer factor standardised for effective alveolar volume was 71.1% in subjects with abnormal chest radiographs and 86.6% in subjects with normal radiographs (p = 0.10). There was a trend in the correlation between the percentage of predicted transfer factor standardised for effective alveolar volume and total dust exposure (sum of the products of grade of severity of each exposure period and duration of each exposure period in months) (r = 0.40 p = 0.10). This study suggests that there may be a relation between inhalation of the dust of this form of aluminium silicate and pulmonary fibrosis.

Pindolol and pulmonary fibrosis

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Pulmonary function in firefighters: acute changes in ventilatory capacity and their correlates

A group of 39 firefighters was examined during routine firefighing duty. Following smoke exposure the average decrease in one-second forced expiratory volume (FEV1.0) was 0.05 litre (137 observations). This decline in FEV1.0 was related to the severity of smoke exposure as estimated by the firefighter and to the measured particulate concentration of the smoke to which he was exposed. Decreases in FEV1.0 in excess of 0.10 litre were recorded in 30% of observations. Changes in FEV1.0 resulting from a second exposure to smoke on the same tour of duty were greater when smoke exposure at the previous fire was heavy. The repeated episodes of irritation of the bronchial tree that have been documented in this investigation may explain the origin of the previously observed chronic effect of firefighting on respiratory symptoms and pulmonary function.

Pulmonary function in coal workers with Caplan's syndrome and non-rheumatoid complicated pneumosoniosis

This retrospective study compares the pulmonary function of 24 coal workers with Caplan's syndrome with that of 36 subjects with non-rheumatoid progressive massive fibrosis (PMF). Allowing for differences in radiographical category, age, years worked underground, and smoking, obstruction to air flow as reflected in the one-second forced expiratory volume, the vital capacity, and the ratio of residual volume to total lung capacity, was significantly less in subjects with Caplan's syndrome. No significant differences in transfer factor were found. These findings may be explained by the different pathological features of the two entities. Selection bias does not appear to be responsible for the differences observed between the groups, but studies designed to eliminate this would be desirable.

Mortality among Boston firefighters, 1915--1975

Although the nature of firefighting involves particular health hazards, previous mortality and morbidity studies of firemen have produced inconsistent evidence for an increased risk of mortality from cardiovascular disease, respiratory disease, cancer and accidents. Mortality experience since 1915 has been examined in 5655 Boston firefighters, comprising all male members of the city fire department with three or more years of service. The observed cause of death as stated on the death certificates of 2470 deceased firefighters has been compared with the numbers expected based on rates for the male population of Massachusetts and of the United States of America. Among all firefighters, deaths from all causes were 91% of expected. The standardised mortality ratio (SMR) was markedly reduced (less than 50) for infectious disease, diabetes, rheumatic heart disease, chronic nephritis, blood diseases and suicide. The SMR was 86 for cardiovascular deaths, 83 for neoplastic deaths, and 93 for respiratory deaths. The SMR for accidents was 135 for active firefighters. The results suggest that the survival experience of firefighters is strongly influenced by strict entry selection procedures, ethnic derivation, and sociocultural attributes of membership. While excessive morbidity has been demonstrated in firefighters, there does not appear to be a strong association between occupation and cause-specific mortality.

Peripheral pooling of bronchographic contrast material: evidence of its relationship to smoking and emphysema

Sixty-six subjects, mainly derived from various occupational groups and one-third of whom admitted to dyspnoea on exertion, have been grouped according to the appearance of their peripheral airways at bronchography with oily propyliodone. Eleven subjects showed marked peripheral pooling of radiographic contrast material, 22 showed mild or moderate pooling, and in 33 peripheral pools were absent. Pooling was not seen in non-smoking subjects. In the group of subjects without pooling, pulmonary function in non-smokers and subjects with a history of smoking was similar. Subjects with marked pooling had a significantly lower pulmonary diffusing capacity (transfer factor) and evidence of loss of pulmonary elastic recoil when compared with subjects with absent peripheral pooling. These results indicate that bronchographic peripheral pooling is associated with the physiological changes of panacinar pulmonary emphysema and suggest that a causal relationship may exist between the organic bronchiolar lesion of pooling and the peripheral parenchymal lesion of panacinar emphysema.

Lung function in fire fighters, II: a five year follow-up fo retirees

In a study of the chronic effects of fire fighting on lung function, 1,768 employees from the Boston Fire Department were examined in 1970. From this cohort, 109 firefighters who retired in the period 1970 to 1975 have been restudied with questionnaire and ventilatory function tests. The observed vulues for pulmonary function when expressed as a per cent of predicted are consistently slightly below 100 per cent. The expected effect of cigarett smoking on lung function was demonstrated. The results suggest thetirement) are important in reducing the effect of fire fighting on subjects who may be adversely affected by the inhalation of combustion products.

Lung function in fire fighters, I: a three year follow-up of active subjects

From a cohort of 1,768 Boston fire fighters studied initially in 1970, pulmonary function measurements were repeated on 1, 146 active subjects in 1974. The mean time between examinations was 3.4 years. The data on 1,430 subjects after one year of follow-up had indicated excessive decrements in levels of forced vital capacity and one-second forced expiratory bolume which were related to the frequency of fire exposure. The annual decline over three years was less than that observed over one year and could not be related to the number of fires fought or to other indices of acute fire exposure. Selection factors within the fire department appear to be important in protecting fire fighter from continued loss ventilatory capacity.

Pulmonary function in granite dust exposure: a four-year follow-up

Pulmonary function studies were performed on 974 workers in Vermont granite sheds in 1974. Of these subjects, 668 had been studied 4 years earlier and had remained in jobs in which their exposure to granite dust had not changed based on dust concentrations measured during 1970. The yearly decrement in pulmonary function observed in the 668 granite shed workers was excessive (0.07 to 0.08 liter per year for forced vital capacity and 0.05 to 0.07 liter per year for forced expiratory volume in 1 sec). This exceeded the expected decrement derived from several other occupational and population groups. Studies from this laboratory and published cross-sectional and longitudinal data consistently indicate a decrement of no more than 0.03 to 0.04 liter per year in both forced vital capacity and forced expiratory volume in 1 sec. The observed decrements were independent of exposure groups and not accounted for by cigarette smoking. In 528 additional granite shed workers, decrements in ventilatory capacity had been measured for one, 2, or 3 years and were consistently of the same order of magnitude. Dust concentrations within defined jobs and between granite sheds showed great variability. Despite this, a suggestive relationship between exposure and decrement in ventilatory function was demonstrated at the end of 2 years; however, at the end of 4 years the relationship could no longer be shown with these exposure groupings. The difficulty in characterizing individual dust exposures and projecting dust concentrations for several years is considered to account for the absence of a dose-response relationship at the 4-year follow-up. The results of this study suggest that our previous estimates of annual deterioration in ventilatory capacity attributable to work in granite sheds are underestimates. We conclude that present dust concentrations in Vermont granite sheds cause excessive deterioration of lung capacity. To prevent these effects, dust concentrations must be lowered.

Pulmonary elastic recoil and diffusing capacity in subjects with intermediate concentrations of alpha-1 antitrypsin

Serum from 224 males investigated in a prospective study of respiratory disorders in a recently established asbestos industry has been estimated for alpha-1 antitrypsin (AAT) concentration by single radial immunodiffusion. Mean AAT concentration was 213-4 mg/dl). No subject with a markedly reduced level was found. A comprehensive range of lung function tests sensitive to changes anticipated in emphysema at a preclinical stage, included measurements of diffusing capacity and pulmonary elastic recoil. The 26 subjects with AAT concentration less than 150 mg/dl, were regarded as likely to comprise a majority of genotypes MZ and SS, and the 19 subjects with AAT concentration greater than 300 mg/dl were considered to comprise mainly MM. No difference in pulmonary function could be demonstrated between these two groups. Evidence of diminished pulmonary elastic recoil was found in nine smoking subjects whose AAT concentrations were normal and also in one young non-smoking subject with moderately severe asthma, whose AAT concentration was 140 mg/dl. It is concluded that in a male working population, evidence of diminished pulmonary elastic recoil is not a function of AAT concentration.