Hans Weill

Asbestosis as a precursor of asbestos related lung cancer: results of a prospective mortality study

A prospective mortality study of 839 men employed in the manufacture of asbestos cement products in 1969 examined lung cancer risk in relation to lung fibrosis seen on chest x ray film, controlling for age, smoking, and exposure to asbestos. Twenty or more years after hire, no excess of lung cancer was found among workers without radiographically detectable lung fibrosis, even among long term workers (greater than or equal to 21.5 years); nor was there a trend in risk by level of cumulative exposure to asbestos among such workers. By contrast, employees with small opacities (greater than or equal to 1/0; ILO classification) experienced a significantly raised risk of lung cancer (nine observed deaths v 2.1 expected), even though their exposures to asbestos were similar to the exposures of long term workers without opacities. In this population, excess risk of lung cancer was restricted to workers with x ray film evidence of asbestosis, a finding consistent with the view that asbestos is a lung carcinogen because of its fibrogenicity.

Lung Function Consequences of Dust Exposure in Asbestos Cement Manufacturing Plants

A comprehensive study of health effects associated with the mixed dust exposure in this industry has included the collection of clinical, radiographic, lung function, and dust exposure data on 859 workers in two plants. Evidence is presented supporting a dose-response relationship between indexes of dust exposure and lung function, similar to the previously reported relationship with extent of x-ray film changes using the ILO U/C classification. Lung volumes and maximum expiratory flow rates decrease in relation to increasing cumulative dust exposure while pulmonary diffusing capacity (DL) is not dust-dose related. Worders who had crocidolite exposure had smaller lung volumes, lower expiratory flow rates, and reduced DL when compared with those having only chrysotile exposure. When the study population is divided into exposure groups, data thus far analyzed suggest that the chest x-ray film will reveal small opacities as early as significant functional changes can be detected, but individuals may have functional reduction prior to the appearance of x-ray film changes.

Crystalline silica exposure, radiological silicosis, and lung cancer mortality in diatomaceous earth industry workers

BACKGROUND The role of silicosis as either a necessary or incidental condition in silica associated lung cancer remains unresolved. To address this issue a cohort analysis of dose-response relations for crystalline silica and lung cancer mortality was conducted among diatomaceous earth workers classified according to the presence or absence of radiological silicosis. METHODS Radiological silicosis was determined by median 1980 International Labour Organisation system readings of a panel of three “B” readers for 1809 of 2342 white male workers in a diatomaceous earth facility in California. Standardised mortality ratios (SMR) for lung cancer, based on United States rates for 1942–94, were calculated separately for workers with and without radiological silicosis according to cumulative exposures to respirable crystalline silica (milligrams per cubic meter × years; mg/m3-years) lagged 15 years. RESULTS Eighty one cases of silicosis were identified, including 77 with small opacities of ⩾1/0 and four with large opacities. A slightly larger excess of lung cancer was found among the subjects with silicosis (SMR 1.57, 95% confidence interval (CI) 0.43 to 4.03) than in workers without silicosis (SMR 1.19, 95% CI 0.87 to 1.57). An association between silica exposure and lung cancer risk was detected among those without silicosis; a statistically significant (p = 0.02) increasing trend of lung cancer risk was seen with cumulative exposure, with SMR reaching 2.40 (95% CI 1.24 to 4.20) at the highest exposure level (⩾5.0 mg/m3-years). A similar statistically significant (p = 0.02) dose-response gradient was observed among non-silicotic subjects when follow up was truncated at 15 years after the final negative radiograph (SMR 2.96, 95% CI 1.19 to 6.08 at ⩾5.0 mg/m3-years), indicating that the association among non-silicotic subjects was unlikely to be accounted for by undetected radiological silicosis. CONCLUSIONS The dose-response relation observed between cumulative exposure to respirable crystalline silica and lung cancer mortality among workers without radiological silicosis suggests that silicosis is not a necessary co-condition for silica related lung carcinogenesis. However, the relatively small number of silicosis cases in the cohort and the absence of radiographic data after employment limit interpretations.

Asbestos exposure, asbestosis, and asbestos-attributable lung cancer.

The study was designed to test the hypothesis that the risk of lung cancer from asbestos exposure is confined to persons with radiographic evidence of pulmonary fibrosis. Occupational and smoking histories were obtained from 271 patients with a confirmed diagnosis of primary lung cancer and 678 referents (279 with other respiratory disease and 399 with cardiac disease). Histories were reviewed blind to assess the timing, duration, and probability of exposure to asbestos. To allow for a lag between asbestos exposure and the development of lung cancer, subjects were classified by the time they had spent in an occupation entailing definite or probable exposure more than 15 years before diagnosis. The presence and extent of fibrosis was assessed blindly from chest radiographs by three readers and scored for small opacities with the ILO 1980 International Classification of Radiographs of the Pneumoconioses. 93 (34-3%) cases had worked in an occupation with definite or probable asbestos exposure compared with 176 (25.8%) referents (crude odds ratio for lung cancer 1-49, 95% Cl 1.09-2.04). After adjustment for age, sex, smoking history, and area of referral, the odds ratio (95% Cl) was 2.03 (1 00-4.13) in the subgroup of 211 with a median ILO score for small parenchymal opacities of 1/0 or more, and 1 56 (1.02-2.39) in the 738 with a score of 0/1 or less (ie, those without radiological evidence of pulmonary fibrosis). These results suggest that asbestos is associated with lung cancer even in the absence of radiologically apparent pulmonary fibrosis. (Lancet 1995;345:1074-8)

Follow up study of workers exposed to man made mineral fibres.

A survey of workers in seven man made mineral fibre (MMMF) production plants, the subject of a previous report, was conducted, with other blue collar workers serving as regional comparisons. Based on the median reading of chest radiographs by five readers, a low prevalence of small opacities, all at the 1/0 and 1/1 profusion levels, was again found: for workers with MMMFs, 23/1435 (1.6%); for comparison workers, 2/305 (0.7%). Spirometric measurements indicated generally healthy populations, and were not related to presence of opacities. Ninety three per cent (21/23) of MMMF workers with opacities worked at the two plants with the highest exposures to fine fibres, resulting in a dose-response relation across plants. For one location, the prevalences of opacities for the MMMF and comparison workers were not significantly different (5.9% (13/220) v 3.1% (2/65)). No comparison x ray films were obtained for the MMMF plant with the highest prevalence (6.6%), so a second phase of the study was conducted, with pre-employment films from these two plants. On this second reading, the prevalence of opacities was lower; there were no significant differences between the two groups of films, and no relation between opacities and exposure indices. There was considerable inter and intrareader variability. These results indicate no adverse clinical, functional or radiographic signs of effects of exposure to MMMFs in these workers.

The Effect of Isoniazid on Transaminase Levels

Abstract To determine if something other than isoniazid causes the serum glutamic-oxalacetic transaminase (SGOT) elevations in isoniazid recipients, tuberculin-positive hospital employees receiving...

Early lipoid pneumonia: Roentgenologic, anatomic and physiologic characteristics

Abstract The clinical variability of lipoid pneumonia is illustrated by three cases. The evolution of the disease has been demonstrated by serial roentgenograms. Rosettes and stippling are seen on the early roentgenograms and correspond to acinar consolidations in the experimental disease. When aspiration of oil continues, recent foci of disease are found together with areas of granuloma and fibrosis. That this disease can produce significant functional disturbance has been demonstrated in an asymptomatic patient with diffusely distributed lesions. Significant restriction of lung volume with poor gas exchange was present at a time when gross distortion of the lung had not taken place. Diagnostic methods for the demonstration of oil in the sputum are illustrated and briefly discussed; an alternative method utilizing fluorescence microscopy has been introduced.

Bagassosis: A Study of Pulmonary Function in 20 Cases

Excerpt The existing literature on bagassosis contains only a few incomplete studies of pulmonary function. The need for complete studies in a significant number of cases using modern physiological...

Incomplete Consolidation in Pneumococcal Lobar Pneumonia Complicating Pulmonary Emphysema

Abstract Chest roentgenograms and hospital records of 104 patients with pneumonia whose admission blood cultures were positive for pneumococci were reviewed. Clinical characteristics, laboratory an...

The “Helsinki Criteria” for Attribution of Lung Cancer to Asbestos Exposure: How Robust Are the Criteria?

T ‘‘Helsinki Criteria’’ were put forward as ‘‘state-of-the-art’’ criteria for the diagnosis and attribution of certain lung and pleural disorders to asbestos exposure by a group which convened in Helsinki in 1997, and were further updated in 2004.1,2 The Helsinki Criteria were purported to be the work of a ‘‘consensus conference’’ whose purpose was to develop guidelines for diagnosing individual cases of asbestosrelated diseases. Interestingly, the documents that have resulted from the meeting bear a striking resemblance to the review articles written by Henderson et al3,4 several years prior to the meeting, one of which in fact is not a scientific reference at all but a legal briefing book.3 The recommended criteria are increasingly being used for medicolegal purposes, often by ‘‘experts’’ indiscriminately, with no specific knowledge as to how they were derived and how they should be applied. In fact, the article uses a considerable amount of medicolegal jargon and despite the appellation of ‘‘consensus conference’’ is clearly slanted toward a particular medicolegal viewpoint. The most controversial issues are