Asbestosis mortality in the USA: facts and predictions.

BACKGROUND: Mortality trends in the USA show that deaths from asbestosis are increasing, while deaths related to other pneumoconiosis are declining. OBJECTIVES: To analyse the association between asbestos consumption and asbestosis mortality trends. METHODS: In an epidemiological time series study, we used a modern computer-intensive local regression method to evaluate the relationship between asbestos consumption per capita (1900-2006) as the predictor variable and number of deaths from asbestosis (1968-2004). The predictor variable was progressively lagged by annual increments from 30 to 60 years and the goodness of fit assessed for each lag period. The model having the smallest Akaike's Information Criteria was used to derive extrapolated estimates of future mortality based on more recent asbestos consumption data. RESULTS: Asbestos consumption per capita reached a peak in 1951 and gradually declined until 1973, when it started to drop rapidly. In 2006, it was 0.0075 kg/person/year. There were 25 564 deaths from asbestosis over the period 1968-2004. The best-fitting model (adjusted coefficient of determination (R(2)) = 99.7%) for 1968-2004 deaths from asbestosis used asbestos consumption per capita 48 years prior (1920-1956) and the log value of asbestos consumption per capita 43 years prior (1925-1961). This model predicts a total of 29 667 deaths (95% CI 19 629 to 39 705) to occur during 2005-2027 (an average of 1290 deaths per year). CONCLUSIONS: This study demonstrates a clear association between asbestos consumption and deaths from asbestosis and indicates that asbestosis deaths are not expected to decrease sharply in the next 10-15 years.

Rapidly progressive coal workers' pneumoconiosis in the United States: geographic clustering and other factors.

BACKGROUND: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers' pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue to occur among coal miners. AIMS: To identify US miners with rapidly progressive CWP and to describe their geographic distribution and associated risk factors. METHODS: Radiographic evidence of disease progression was evaluated for underground coal miners examined through US federal chest radiograph surveillance programmes from 1996 to 2002. A case of rapidly progressive CWP was defined as the development of PMF and/or an increase in small opacity profusion greater than one subcategory over five years. County based prevalences were derived for both CWP and rapidly progressive cases. RESULTS: A total of 886 cases of CWP were identified among 29 521 miners examined from 1996 to 2002. Among the subset of 783 miners with CWP for whom progression could be evaluated, 277 (35.4%) were cases of rapidly progressive CWP, including 41 with PMF. Miners with rapidly progressive CWP were younger than miners without rapid progression, were more likely to have worked in smaller mines (<50 employees), and also reported longer mean tenure in jobs involving work at the face of the mine (in contrast to other underground mining jobs), but did not differ with respect to mean underground tenure. There was a clear tendency for the proportion of cases of rapidly progressive CWP to be higher in eastern Kentucky, and western Virginia. CONCLUSIONS: Cases of rapidly progressive CWP can be regarded as sentinel health events, indicating inadequate prevention measures in specific regions. Such events should prompt investigations to identify causal factors and initiate appropriate additional measures to prevent further disease.

Broncholithiasis and lithoptysis associated with silicosis.

A case of broncholithiasis associated with massive silicosis is reported, showing a rare aspect of parenchymal lesions generating broncholiths as well as the presence of recurrent lithoptysis, with subsequent regression of radiological lesions. Aetiological, clinical, physiopathological, and radiological aspects of the disease are discussed, demonstrating the importance of the use of computed tomography in diagnosis. The mineralogical analysis of expectorated fragments is also shown.