Serum IgE and lung function in workers exposed to phthalic anhydride

Summary A total of 23 phthalic anhydride (PA)-exposed workers (air levels up to 17 mg/m³) showed significantly (P<0.01) more workrelated symptoms in their eyes (48% vs 6%) and nose (39% vs 0) than did 18 unexposed control subjects. Two of the exposed workers had PA-associated asthma. Surprisingly, the control group exhibited significantly (P<0.05) more symptoms of nonspecific bronchial hyperreactivity (44% vs 13%). The exposed workers showed significantly higher levels of total serum IgE (medians, 32 vs 15 kIU/l, P<0.05), although values for specific IgE against PA did not differ. This may indicate that such exposure can facilitate the entry of common allergens. There was a significant difference in PA-specific IgG [enzyme-linked immunosorbent assay (ELISA) ratios 0.21 vs 0.12; P<0.01]. There were no differences in lung function with regard to vital capacity (VC) and forced expiratory volume (FEV₁), closing volume expressed as a percentage of VC (CV%), volume of trapped gas (VTG) before and after inhalation of metacholine, or carbon monoxide transfer factor (TLCO), whereas exposed workers displayed significantly higher late expiratory flow rates (MEF_5O and MEF₂₅). In a [^99mTc]-diethylenetriamine penta-acetate (DTPA) clearance test, there was no difference between exposed subjects and controls. In summary, exposure to PA did not cause subclinical effects of the lungs. Subjects with lower-airway symptoms showed lower FEV₁, MEF₅₀, and MEF₂₅ values and higher VTG (after metacholine) than did those without symptoms. Six subjects with chronic bronchitis displayed significantly (P<0.05) higher VTG (before metacholine) and TLCO, than those without this ailment. Thus, VC, CV and the [^99m99mTc]-DTPA test were not affected by the lung disorder.     

上海市大气污染对小学生肺功能小气道指标的急性效应研究

目的 分析上海市复合型大气污染对儿童肺功能小气道指标的急性影响。方法 在上海市内环、中环和外环各选择一所小学（A、B和C）,每所学校各随机抽取3~5年级一个班级学生为研究对象（共233人）;A、B两校于2013年12月和C校于2014年12月测试肺功能3次,各校分别于次年5-6月测试第4次肺功能。同时收集同期三校就近环境空气质量监测点大气细颗粒物（PM_2.5）、可吸入颗粒物（PM₁₀）、二氧化硫（SO₂）和二氧化氮（NO₂）污染物数据和气象监测数据;采用线性混合效应模型分析大气污染对肺功能小气道指标的影响。结果 控制气象因素和个体因素后,PM_2.5、PM₁₀滞后2 d和累计滞后2 d、SO₂累计滞后2 d和NO₂检测当日浓度每增加一个四分位间距（IQR）,儿童25%肺活量最大呼吸流速（MEF_25%）、50%肺活量最大呼吸流速（MEF_50%）、75%肺活量最大呼吸流速（MEF_75%）和用力呼气中段流速（FEF_25%~75%）均有不同程度的降低（P<0.05或P<0.01）;双污染物模型分析显示SO₂和NO₂分别叠加PM_2.5和PM₁₀污染时,滞后效应值大于SO₂和NO₂单独存在时（P<0.05）。结论 上海市大气污染物短期暴露与儿童肺功能小气道指标变化呈负相关,并存在滞后效应及累计滞后效应。     

Lung health among plumbers and pipefitters in Edmonton, Alberta

OBJECTIVES: A cross sectional study was undertaken to assess lung health among plumbers and pipefitters. Respiratory symptoms, lung function, and radiographic changes among 99 actively employed plumbers and pipefitters with > or = 20 years of union membership were compared with 100 telephone workers. METHODS: A respiratory symptom questionnaire was administered, including smoking and occupational histories. Spirometry was conducted according to standard criteria. Posteroanterior chest radiographs were evaluated by two experienced chest physicians, with a third arbitrating disagreed films. Members of the union were categorised as pipefitters (n = 57), plumbers (n = 16), or welders (n = 26), based on longest service, and compared with the telephone workers and internally (between groups). Lung health was also compared with employment in several work sectors common to Alberta for time, and for time weighted by exposure to dust and fumes. RESULTS: Compared with the telephone workers, plumbers and pipefitters had more cough and phlegm, lower forced vital capacity, and more radiographic changes (20% with any change), including circumscribed (10%) and diffuse pleural thickening (9%). None of the plumbers and pipefitters had small radiographic opacities. Among the three subgroups of workers, plumbers had the highest prevalence of radiographic changes. Both plumbers and pipefitters showed higher odds ratios for cough and phlegm than the welders. No differences between groups were found for lung function. Indicators of lung health were not related to work in any sector. CONCLUSIONS: Plumbers and pipefitters had increased prevalence of symptoms suggestive of an irritant effect with no evidence of bronchial responsiveness. The chest radiographs showed evidence of asbestos exposure, especially in the plumbers, but at lower levels than previously reported. Health screening programmes for these workers should be considered, although the logistical problems associated with screening in this group would be considerable.

 

     

High Prevalence of Reversible Airway Obstruction in Asbestos-Exposed Workers

In this retrospective study of 97 male workers exposed to asbestos for 2-50 yr, data were collected on chest x-ray findings and lung function, including lung volumes, forced expiratory flow rates (i.e., forced expiratory volume in 1 sec [FEV_1.0], forced expiratory flow measured between 25% and 75% of forced vital capacity [FEF_25-75%]), airway resistance (R_aw), carbon monoxide (CO)-diffusing capacity, and the existence of airway obstruction reversible by a β-adrenergic agonist (RAO). The authors performed multiple-regression analyses to correlate the variations in lung function data with age, smoking habits, duration of asbestos exposure, and time since last exposure. Occupational activities of subjects that might induce specific lung abnormalities were also considered. No significant decrease was seen in lung volumes or CO-diffusing capacity; however, a decrease in FEV_1.0 and an increase in R_aw were measured in 65% of the subjects, and an isolated decrease in FEF_25-75% occurred in only 18%. There was no difference in lung-function data between subjects who had chest x-ray signs of abnormalities (n = 59) and those who did not (n = 38). A significant relationship was found between the decrease in FEV_1.0 and age; however, no correlation was noted between altered lung function and cigarette smoking, duration of asbestos exposure, or time since last exposure. RAO prevalence was higher (34%) than previously reported (9%) in subjects with chronic obstructive pulmonary disease (COPD) who were not exposed to asbestos or outdoor pollution. The RAO prevalence in asbestos-exposed workers was nearly the same as that measured in COPD subjects who lived downtown and who were exposed to outdoor pollution (36%). The high RAO prevalence in asbestos-exposed workers was found in 43% of subjects who were exposed only to asbestos, and in 33% of subjects who were also exposed to air pollution due to their occupational activities. It is hoped that the observations in this study will encourage practitioners to check for RAO in asbestos workers who use inhaled bronchodilators.     

Pulmonary function and symptoms of welders

 Objectives: As the findings on changes in pulmonary function of welders have been inconsistent, this study aimed to analyze respiratory symptoms and pulmonary function among welders and controls with particular emphasis on small airways dysfunction. Methods: Cross-sectional analysis, using spirometry and a standardized questionnaire, was used to evaluate 521 participants, 166 of whom (64 welders and 102 controls) were evaluated for pulmonary symptoms, occupational inhalative exposures, leisure time activities, and anamnestic data. Results: The welders reported more pulmonary symptoms than the controls. They exhibited a decreased mean expiratory flow (MEF) at 25% and 50% of vital capacity (MEF₂₅, MEF₅₀) while the other parameters tested (forced vital capacity, forced expiratory volume in 1 s) were unchanged compared with the controls. Multivariate regression analysis revealed that smoking explained the observed variance; only in MEF₂₅ the duration of welding exposure had a significant influence on this parameter. Conclusions: The significantly reduced flow values among the welders compared with the controls indicates the presence of small airways disease. Differences in smoking habits accounted for more than double the differences in MEF₂₅ than did chronic welding fume exposure, confirming the role of the former as the main risk factor leading to the decline in lung function. Longitudinal studies are needed to evaluate the long-term effects of chronic welding fume exposure, in particular with a view to identifying especially susceptible workers. Received: 20 April 1996/Accepted: 13 May 1996     

Occupational-type exposure tests and bronchoalveolar lavage analyses in two patients with byssinosis and two asymptomatic cotton workers

Summary Two workers suffering from stage III byssinosis and claiming for compensation were examined. Bronchial obstruction was present in one case. MEF_25–75 values were significantly reduced and bronchial hyperreactivity was present in both subjects. Occupational-type exposure tests with cotton dust resulted in significant decreases in arterial oxygen pressure for more than 2 h and were associated with an obstructive ventilation pattern in one of the patients. Prolonged hypoxemia which is not paralleled by lung function changes is probably typical for byssinosis patients since we have never seen this in inhalative challenge tests with various environmental antigens and other occupational substances including flour dust. No specific IgE or IgG antibodies could be detected. In the two patients a hitherto unknown significant increase in CD23+ lymphocytes and granulocytosis were detected by bronchoalveolar lavage (BAL). Corresponding investigations in two cotton workers without any evidence of byssinosis revealed neither lung function changes after the exposure test nor striking BAL findings. Our results demonstrate the diagnostic value of specific challenge tests and BAL investigations in patients suffering from byssinosis, which is often difficult to diagnose.     

Lung function in asbestos-exposed workers, a systematic review and meta-analysis

Background

A continuing controversy exists about whether, asbestos exposure is associated with significant lung function impairments when major radiological abnormalities are lacking. We conducted a systematic review and meta-analysis in order to assess whether asbestos exposure is related to impairment of lung function parameters independently of the radiological findings.

Methods

MEDLINE was searched from its inception up to April 2010. We included studies that assessed lung function parameters in asbestos exposed workers and stratified subjects according to radiological findings. Estimates of VC, FEV₁ and FEV1/VC with their dispersion measures were extracted and pooled.

Results

Our meta-analysis with data from 9,921 workers exposed to asbestos demonstrates a statistically significant reduction in VC, FEV₁ and FEV₁/VC, even in those workers without radiological changes. Less severe lung function impairments are detected if the diagnoses are based on (high resolution) computed tomography rather than the less sensitive X-ray images. The degree of lung function impairment was partly related to the proportion of smokers included in the studies.

Conclusions

Asbestos exposure is related to restrictive and obstructive lung function impairment. Even in the absence of radiological evidence of parenchymal or pleural diseases there is a trend for functional impairment.     

Lung health among boilermakers in Edmonton,Alberta

Background Construction boilermakers may be exposed to a variety of substances, including asbestos and welding fumes. Past studies of boilermakers have shown increases in mortality from lung cancer and asbestosis and radiographic changes consistent with asbestos exposure. Methods Respiratory symptoms, lung function, and radiographic changes were compared for 102 actively employed boilermakers with 20 or more years of union membership and 100 telephone workers. Posteroanterior chest radiographs were evaluated by two experienced chest physicians, with a third arbitrating disagreed films. Union members were further categorized as boilermakers (n = 50) or welders (n = 52), based on longest service. Lung health was also compared with employment in a number of work sectors for time, and time-weighted exposure to dust and fumes. Results Boilermakers had more respiratory symptoms than telephone workers, but lung function did not differ. Radiographic changes were more common among the boilermakers (20% with any change, 8% circumscribed, and 9% diffuse pleural thickening). None of the boilermakers had small radiographic opacities. Several symptoms suggestive of bronchial responsiveness were associated with fume exposures in the gas and oil industry. Workers whose longest service was as a boilermaker demonstrated more symptoms than did welders. FEV₁, FEV₁/FVC, FEF_25–75, and FEF₅₀ were significantly lower among boilermakers compared with welders. Conclusion Health screening programs for these workers are warranted. Am. J. Ind. Med. 34:381–386, 1998. © 1998 Wiley-Liss, Inc.     

Pulmonary function of control and industrially exposed Nigerians in asbestos,textile, and toluene diisocyanate-foam factories

The pulmonary function of 120 non-industrially exposed Nigerians and of workers in an asbestos-cement factory, a cotton textile factory, and a TDI-foam factory was investigated. The pulmonary function of the control subjects was significantly (P < 0.001) higher than that of any of the control subgroups. The total particulate levels in the factories corresponded to the level of dust-generating activity. The highest suspended particulate level in the asbestos-cement factory was 18.3 mg·m^?3 while the highest level in the textile factory war 14.94 mg·m^?3. The highest total respirable fiber content in the asbestos-cement factory was 6.63 f·cm^?3 and this occurred in the cement and asbestos mixing section. It seemed that the greatest risk to pulmonary function for the exposed subjects resulted from exposure to cotton dust, however, a probable acute exposure to toluene diisocyanate among a subgroup that had an exposure duration of about a year produced the highest depression of lung function observed among the exposed subjects. It seems that the pulmonary function of the Nigerian “normal” population has not changed in a decade, after an apparent increase in industrialization. The pulmonary function equations developed in this study showed good predictability and the FEV₁ and FVC values calculated from these equations closely matched those calculated from equations developed for other African subjects.     

Dust- and endotoxin-related acute lung function changes and work-related symptoms in workers in the animal feed industry

Reported respiratory and related symptoms during work were compared between 265 exposed animal feed workers and a control group consisting of 175 external controls and nonexposed workers in the animal feed industry. Symptoms indicating respiratory and nasal irritation were significantly increased in the animal feed workers. Prevalences ranged from 9% (cough) to 21% (sneezing). Reported cough after work was also significantly increased. In 119 workers, a total of 457 across-shift spirometric lung function changes were measured. Almost all lung function variables showed a decrease during the work shift, as could be expected since the circadian rhythm is in a downward phase during the measurement period (2 p.m.-10 p.m.). When the workers were grouped into dust and endotoxin exposure categories according to their job titles, and exposure-response trend was seen for maximum mid-expiratory flow (MMEF) and maximum expiratory flow rate at 50% of vital capacity (MEF₅₀). The effect of endotoxin was stronger than that of dust, both in magnitude and significance. For the same lung function variables and for forced expiratory volume in 1 second (FEV₁) and MEF₂₅, a significant across-week change was also detected. The results of this study are in concordance with other studies that indicate acute effects on lung function and elevated prevalences of respiratory symptoms during work caused by exposure to grain dust.     

Asbestos Bodies in Normal Lung of Western Mediterranean Populations with No Occupational Exposure to Inorganic Dust

The aim of this study was to determine the following: (a) asbestos body count in lung tissue of different western Mediterranean populations; (b) the association, if any, of urban industrial residence with higher lung tissue asbestos body counts in this geographical area; and (c) the risk factor that environmental asbestos exposure posed for lung cancer in our population. Lung-tissue samples were studied in three groups of subjects from the general population: (1) group A comprised 18 patients from Barcelona's urban industrial area (mean age = 62.2 y, standard deviation [SD] = 13.6); (2) group B comprised 16 patients who lived in a rural area of Albacete in the south of Spain (mean age = 62.2 y, SD = 13.7); and (3) group C comprised 8 patients who had been diagnosed with lung cancer, who lived in or near Barcelona, and who had never been exposed occupationally to asbestos (mean age = 62.1 y, SD = 7.4). A wet lung/dry lung weight ratio was determined. In group A, asbestos bodies were observed in 9 of 18 (50%) subjects, and asbestos bodies numbered 52.35 per g dry lung (SD = 101.72) (upper limit of normality [higher value] = 430.12 asbestos bodies per g dry lung). In group B, asbestos bodies were observed in 2 of 16 (12.5%) subjects, and asbestos bodies numbered 5.37 per g dry lung (SD = 8.79) (upper limit normality = 35.15 asbestos bodies per g dry lung). In group C, we observed asbestos bodies in 2 of 8 subjects (25.0%), and asbestos bodies numbered 20.59 per g dry weight (SD = 24.10). Comparison between groups A and B indicated small differences in the prevalence of asbestos bodies (i.e., Barcelona 50%, Albacete 12.5%; p = .057 [chi-square test]), as well as small differences in asbestos body counts (i.e., asbestos bodies per g dry lung; Mann-Whitney U-test, p < .001). The results of these comparisons evidenced a higher exposure to asbestos in the urban industrial environment. No statistically significant differences were found between groups A and C (chi-square test/Mann-Whitney U-test: p > .05). We concluded that, in western Mediterranean populations, normal lung asbestos body counts were higher in urban industrial inhabitants than in rural inhabitants; however, in both populations, there was a low prevalence of asbestos bodies. Our results did not suggest that environmental exposure to asbestos played a role in the pathogenesis of lung cancer in subjects who had never been exposed occupationally to asbestos and who had lived in western Mediterranean areas.     

Relation between lung asbestos fibre burden and exposure indices based on job history.

Lung asbestos burden was compared with exposure indices derived from job history interviews in 42 male subjects originating from the Montréal Case-Control Study project, 12 of whom had documented asbestos exposed job histories. Job interview data consisting of a chronological timetable of job histories were translated into detailed exposure indices by an expert group of hygienists and chemists. Total and individual asbestos fibre type concentrations were quantified by transmission electron microscopy with fibre identification by energy dispersive chi ray spectrometry after deparaffinisation of tissue blocks and low temperature plasma ashing. Geometric mean or median asbestos content was higher in subjects with an asbestos exposed job history than those without for retained dose of amosite, total commercial amphiboles, and total asbestos fibre. Except for crocidolite fibre diameter, which was significantly less in the lungs of exposed workers, no consistent differences were found in measurements of fibre dimension for any fibre type. Subgroups of subjects exposed to silica, metals, or smokers and non-smokers without significant occupational exposure showed varying patterns of lung asbestos fibre type deficit compared with the asbestos exposed subgroup. There was an overall trend for higher lung asbestos content proportional to higher exposure indices for asbestos representing concentration, frequency, and reliability. These exposure indices as well as duration of exposure (in years) were independent predictors of total asbestos content in regression analyses when combined in a model with age. Stepwise regression indicated that exposure concentration was the most important variable, explaining 32% of the total variation in total asbestos content. Smoking, whether expressed in ever or never smoked dichotomy or in smoked-years, had no relation to lung asbestos content in this model.     

Occupation and male lung cancer: a case-control study in northern Sweden

Using a case-control study comprising about 600 men with lung cancer in northern Sweden the potential risk of different occupations and groups of occupations was studied. Longitudinal data concerning occupation, employment, and smoking habits were obtained by questionnaires. Some occupational groups (underground miners, copper smelter workers, electricians, and plumbers) exposed to previously known lung carcinogenic agents such as radon daughters, arsenic, and asbestos, had considerably increased odds ratios, which persisted after adjustment for smoking. A slightly raised odds ratio was observed in a group of blue collar workers potentially exposed to lung carcinogenic agents; this rise in the group as a whole mainly disappeared after adjustment for smoking. Farmers and foresters had strikingly low odds ratios, which could only partly be explained by their more moderate smoking habits. The population aetiological fraction attributable to occupation was estimated as 9%.     

Acute lung function changes and low endotoxin exposures in the potato processing industry

Work-related respiratory symptoms, acute lung function changes and personal endotoxin exposure were studied in 61 workers from a potato processing plant. According to their job title mean endotoxin exposure level, workers were divided into low (AM = 21 EU/m³) and high (AM = 56 EU/m³) exposure categories. Shortness of breath and chest tightness during work were reported by 18% and 16% of the workers, respectively, mainly in the low endotoxin exposure category. A total of 148 across-shift lung function changes were measured during three consecutive afternoon shifts. The mean FEV₁ and MMEF showed a decrease over the work shift, being largest on the first working day after a 3-day absence from work. Workers exposed to high endotoxin levels showed a larger across-shift decrease in lung function than workers exposed to low endotoxin exposures, the effect being most pronounced on the first day after a 3-day absence from work. At the start of the second work shift, FVC, FEV₁ and MMEF were lower than at the start of the first work shift. This difference was larger for high exposed workers. High exposed workers with work-related respiratory symptoms showed an 8–10% across-shift change in FVC, FEV₁ and MMEF. We conclude that significant across-shift decreases in lung function of potato processing workers is related to endotoxin exposure levels above 53 EU/m³ over 8 hr. Am. J. Ind. Med. 33:384–391, 1998. © 1998 Wiley-Liss, Inc.     

Exposure of UK industrial plumbers to asbestos, Part II: Awareness and responses of plumbers to working with asbestos during a survey in parallel with personal sampling

Throughout the European Union, millions tonnes of asbestos were used in the manufacture of products for building and for industrial installations. Today, in the UK, it is estimated that over half a million non-domestic premises alone have asbestos-containing materials in them and it is recognized that those working in building maintenance trades continue to be at significant risk. In part II, the awareness of UK plumbers to when they are working with asbestos was investigated and compared with the monitored levels reported in part I. The plumbers were issued by post with passive samplers, activity logs to monitor a working week and a questionnaire. The activity logs were used to assess whether maintenance workers were knowingly or unknowingly exposed to airborne asbestos fibres during a course of a working week. The questionnaire was designed to gather information on their: age, employment status, current and past perception of the frequency which they work with asbestos and knowledge of the precautions that should be taken to limit exposure and risk. Approximately 20% of workers reported on the sample log that they had worked with asbestos. There was a high correlation (93%) between the sampling log replies that they were knowingly working with asbestos and measured asbestos on the passive sampler. However, some 60% of the samples had >5 microm long asbestos structures found by transmission electron microscopy (TEM) analysis suggesting that the plumbers were aware of about only one-third of their contacts with asbestos materials throughout the week. This increased to just over one half of the plumbers being aware of their contact based on the results for phase contrast microscopy (PCM) countable asbestos fibres. The results from the questionnaire found that over half of the plumbers replying thought that they disturb asbestos only once a year and 90% of them thought they would work with asbestos for<10 h year-1. Their expectations and awareness of work with asbestos were therefore far lower than found during the period of monitoring. The response to an open question on the precautions to be taken, found that 61% of plumbers would avoid disturbance and 59% would use respiratory protection if they did disturb asbestos. However, their awareness of the methods and the need to reduce their risk by control of emissions at source was very low and suggests that further awareness raising and training is needed. The survey was carried out prior to the introduction of the duty to manage and gives a useful baseline to assess the impact of regulatory initiatives.     

An index of past asbestos exposure as applied to car and bus mechanics

Different ways to describe historic fibre exposure from asbestos-containing friction materials were studied and compared for a group of 103 car and bus mechanics with more than 20 years employment and 15 years of asbestos exposure. A model was constructed to calculate cumulative asbestos exposure from friction materials including duration, intensity and exposure last year. The model is a combination of an additive and a multiplicative model, where an asbestos index was constructed that takes both near field and far field exposure into consideration. The model was based upon data from the international literature and quantitative asbestos measurements performed 1976–1988 in Swedish car repair workshops. The fibres were counted by phase-contrast microscopy with fibre criteria of length >5 μm and aspect ratio ≥3:1. The mechanics' fibre exposure at 398 repair workshops during a period of 48 years were calculated using the model. The mean cumulative exposure was estimated to be 2.6 f ml⁻¹1 year. The annual cumulative exposure was highest for truck mechanics in the early 1960s. The car mechanics had a time-weighted average fibre exposure range of 0.11 – 0.41 f ml⁻¹ (mean 0.21 f ml⁻¹) in 1965 compared to 0.003 – 0.08 f ml⁻¹ (mean 0.021 f ml⁻¹ in 1985. In order to validate the model, the mechanics' fibre exposure estimated using the model were compared with representative asbestos exposure measurements for car mechanics during the 1960s and the 1970s (correlation coefficient = 0.69). Five lung physiological variables (FVC, TLC, FEV₁, TL_co and CV%) were used to study exposure-response relationships. None of the exposure parameters suggested any significant relationship between exposure and decrease in lung function.     

Pulmonary effects of inhaled dust and fumes: Exposure-response study in rubber workers

Lung function changes and respiratory symptoms were investigated in a cross-sectional study in rubber workers exposed to dust and fumes. To exclude acute pulmonary effects related to “rubber fumes,” lung function was measured in curing workers at the start and end of the day shift. Exposure to inhalable dust was measured in all production areas. The results were compared with a reference population from the same geographical region. This study indicates that exposure to “rubber fumes” in curing workers was not related to cross-shift and cross-week decreases in pulmonary function at levels ∼1 mg/m³ (AM) inhalable dust and 260 μg/m³ cyclohexane soluble fraction (CSF). Cross-sectional analyses gave indications for a small loss in pulmonary function in all rubber workers. This decrease in lung function was associated with 10 years of exposure to an average of 2.0 mg/m³ inhalable dust. Our study showed a mean annual decline of 0.08% for the FEV₁/FVC ratio and of 10 ml/s for the MMEF. Self-reported chronic respiratory symptoms were not related to dust exposure. Am. J. Med. 33:16–23, 1998 © 1998 Wiley-Liss, Inc.     

The risk of lung cancer with increasing time since ceasing exposure to asbestos and quitting smoking

Objectives

To examine if the risk of lung cancer declines with increasing time since ceasing exposure to asbestos and quitting smoking, and to determine the relative asbestos effect between non‐smokers and current smokers.

Methods

A cohort study of 2935 former workers of the crocidolite mine and mill at Wittenoom, who responded to a questionnaire on smoking first issued in 1979 and on whom quantitative estimates of asbestos exposure are known. Conditional logistic regression was used to relate asbestos exposure, smoking category, and risk of lung cancer.

Results

Eighteen per cent of the cohort reported never smoking; 66% of cases and 50% of non‐cases were current smokers. Past smokers who ceased smoking within six years of the survey (OR = 22.1, 95% CI 5.6 to 87.0), those who ceased smoking 20 or more years before the survey (OR = 1.9, 95% CI 0.50 to 7.2), and current smokers (<20 cigarettes per day (OR = 6.8, 95% CI 2.0 to 22.7) or >20 cigarettes per day (OR = 13.2, 95% CI 4.1 to 42.5)) had higher risks of lung cancer compared to never smokers after adjusting for asbestos exposure and age. The asbestos effect between non‐smokers and current smokers was 1.23 (95% CI 0.35 to 4.32).

Conclusion

Persons exposed to asbestos and tobacco but who subsequently quit, remain at an increased risk for lung cancer up to 20 years after smoking cessation, compared to never smokers. Although the relative risk of lung cancer appears higher in never and ex‐smokers than in current smokers, those who both smoke and have been exposed to asbestos have the highest risk; this study emphasises the importance of smoking prevention and smoking cessation programmes within this high risk cohort.     

A long-term follow-up of workers exposed to beryllium

ABSTRACT The relationship of features of beryllium disease to the estimated exposure to beryllium has been investigated over a 30-year period at a factory manufacturing beryllium products. The factory opened in 1952. Of the 146 men who had worked there for more than six months up to 1963, 89% were seen at that time and were followed up in 1973. The nine who continued to work in the factory and those who were engaged subsequently were examined in 1977. On each occasion a clinical interview, occupational history, chest radiograph, and assessment of lung function were carried out. The findings of the main survey were related to the beryllium content of the dust measured by mass spectrometry for 1952-60 when over 3000 determinations were made. In no part of the plant did the estimated average daily exposure exceed 2 μg m^-3, and only 9% of individual determinations exceeded this level. Twenty determinations exceeded 25 μg m^-3. During the period under review, four men developed the clinical, radiographic, and physiological features of beryllium disease. Two men acquired abnormal chest radiographs consistent with beryllium disease but without other features, and one developed probable beryllium disease despite the diagnosis not being confirmed at necropsy. The affected men were all exposed to beryllium oxide or hydroxide but in a wide range of estimated doses. In six the changes developed after exposure had ceased; trigger factors including patch testing may have contributed to their illness. Seventeen men recalled episodes of brief exposure to high concentrations of dust, two developed pneumonitis from which they recovered completely, and one developed chronic beryllium disease after a further 23 years' exposure. In subjects without clinical or radiographic evidence of disease no convincing evidence was obtained for any association between the lung function and the estimated exposure to beryllium.     

Asbestos lung burden and asbestosis after occupational and environmental exposure in an asbestos cement manufacturing area: a necropsy study

OBJECTIVE: The largest Italian asbestos cement factory had been active in Casale Monferrato until 1986: in previous studies a substantial increase in the incidence of pleural mesothelioma was found among residents without occupational exposure to asbestos. To estimate exposure to asbestos in the population, this study evaluated the presence of histological asbestosis and the lung burden of asbestos fibres (AFs) and asbestos bodies (ABs). METHODS: The study comprises the consecutive series of necropsies performed at the Hospital of Casale Monferrato between 1985 and 1988. A sample of lung parenchima was collected and stored for 48 out of 55 necropsies. The AF concentration was measured with a TEM electron microscope with x ray mineralogical analysis. The ABs were counted and fibrosis evaluated by optical microscopy. The nearest relative of each subject was interviewed on occupational and residential history. Mineralogical and histological analyses and interviews were conducted in 1993-4. RESULTS: Statistical analyses included 41 subjects with AF, AB count, and interview. Subjects without occupational exposure who ever lived in Casale Monferrato had an average concentration of 1500 AB/g dried weight (gdw); Seven of 18 presented with asbestosis or small airway lung disease (SAL). G2 asbestosis was diagnosed in two women with no occupational asbestos exposure. One of them had been teaching at a school close to the factory for 12 years. Ten subjects had experienced occupational asbestos exposure, seven in asbestos cement production: mean concentrations were 1.032 x 10(6) AF/gdw and 96,280 AB/gdw. Eight of the 10 had asbestosis or SAL. CONCLUSION: The high concentration of ABs and the new finding of environmental asbestosis confirm that high asbestos concentration was common in the proximity of the factory. Subjects not occupationally exposed and ever living in Casale Monferrato tended to have higher AB concentration than subjects never living in the town (difference not significant). The concentrations of ABs and AFs were higher than those found in other studies on nonoccupationally exposed subjects.