Observer variation in classifying chest radiographs for small lung opacities and pleural abnormalities in a population sample.

BACKGROUND: The purpose of this study was to assess inter-and intraobserver variation in the radiographic categories of small lung opacities (profusion) and pleural abnormalities classified according to the ILO classification of pneumoconioses with some modifications. METHODS: Chest radiographs derived from a representative adult population sample (n = 7,095) were classified by two radiologists. Observer variation was assessed on the basis of kappa (kappa)-type statistics. RESULTS: The observers agreed on profusion categories in 69% of cases of the total material. Up to 98% of the classifications fell into the same category or deviated by no more than one category. The corresponding kappa (kappa) coefficient was 0.48 (95% CI = 0.46=0.49) and the weighted kappa 0.72. When a selected subsample was reclassified by the observers, the proportions of crude agreement on profusion of small opacities ranged from 42% to 47% (weighted kappa 0.52-0.55). The proportions of agreement on the main pleural abnormalities were 92% or over, and the corresponding kappa coefficients at least 0.73. CONCLUSION: The classification of lung opacities was subject to considerable observer variation, which calls for caution when results from different studies are compared. This variation, however, rarely exceeded one category, and thus appears to be small enough for meaningful comparisons between groups, at least within a single study.

Fibrosis of the lung and pleura and long-term exposure to wollastonite.

OBJECTIVES: The purpose of this study was to determine whether long-term exposure to wollastonite causes fibrosis of the lung and pleura in humans. METHODS: Forty-nine workers (mean exposure 25 years) in a Finnish limestone-wollastonite mine and mill were examined. Their work histories and symptoms of chronic bronchitis were recorded. The chest radiographs were classified according to the classification of the International Labour Office (1980); a radiographic follow-up from 1981 to 1990 was included. Spirometry and diffusion capacity were measured. Four workers underwent high-resolution computed tomography (HRCT) and bronchoalveolar lavage (BAL). Lung tissue specimens were available for 2 workers. Mineral fibers and asbestos bodies were analyzed from the BAL fluid and lung tissue specimens, which were also analyzed for lung fibrosis. RESULTS: Two workers (4%) had small irregular lung opacities (ILO 1/0), 1 worker (2%) ILO 0/1 of the s/t type. HRCT revealed no parenchymal fibrosis in the 2 workers with the ILO 1/0 classification. Of the 9 workers (18%) with pleural plaques, 5 had been exposed to asbestos. Multivariate logistic regression analyses revealed no association of plaques with the duration of wollastonite or asbestos exposure. Wollastonite fibers or bodies were not found in any of the 4 workers who underwent BAL, nor in either of the workers whose lung tissue specimens were available. CONCLUSIONS: No evidence was found that long-term exposure to wollastonite causes parenchymal fibrosis of the lung and pleura. Furthermore, the findings indicate that wollastonite fibers are poorly retained in human lungs.

Radiographic small lung opacities and pleural abnormalities in relation to smoking, urbanization status, and occupational asbestos exposure in Finland.

The role of smoking and an urban living environment in the etiology of radiographic pleural and pulmonary abnormalities was studied in a population sample that was representative of the Finnish adult population. A total of 7095 full-size chest radiographs were classified according to the International Labor Organization's 1980 classification of radiographs of pneumoconioses, with some modifications. The risk of bilateral pleural plaques was significantly higher among urban men (RR, 2.0) and women (RR, 3.8), even when adjusted for age and probability of occupational asbestos exposure and smoking. The risks of small lung opacities and abnormalities of the visceral pleura were not higher in urban areas. Risks of small lung opacities and thickening of the visceral pleura were positively associated with smoking, and the risk of small lung opacities was also higher among smokers than never-smokers in the population fraction with unlikely occupational asbestos exposure.

Radiographic small lung opacities and pleural abnormalities as a consequence of asbestos exposure in an adult population.

OBJECTIVES: The purpose of this study was to estimate the role of past asbestos exposure as a cause of radiographic small lung opacities and pleural abnormalities in the Finnish adult population. METHODS: The study was conducted in 1978-1981 and was based on a population sample (N = 8000) representative of the Finnish population aged 30 years or over. Full-size chest radiographs and a complete job title history were available for 3811 women and 3274 men. The radiographs were classified according to the 1980 classification of radiographs of pneumoconioses published by the International Labour Office and the work histories according to the probability of occupational asbestos exposure. Age- and smoking-adjusted relative risks of radiographic parenchymal and pleural abnormalities were calculated with the analysis of covariance according to the probability of asbestos exposure. RESULTS: About 13% of the men and 0.8% of the women were classified as probably exposed to asbestos. There was more than 90% agreement in the repeated work history evaluations. The risk of small lung opacities was significantly increased among the probably exposed men [risk ratio (RR) 1.7 for ILO profusion category 1/1 or more and RR 1.6 for profusion category 1/0]. The risk of pleural plaques was increased both among the men (RR 3.0) and the women (RR 4.8) with probable exposure. The risk of thickened horizontal interlobar fissure was also increased among the probably exposed men (RR 1.7). Among the men, the etiologic fraction attributable to occupational asbestos exposure was about 30% for small lung opacities, about 40% for pleural plaques, and about 20% for thickened horizontal fissure. Among the women the etiologic fractions for asbestos were similar for pleural abnormalities, but much lower for parenchymal ones. CONCLUSIONS: Occupational asbestos exposure has been common among Finnish men, and it plays a significant role in the etiology of both pleural and parenchymal abnormalities also at the level of the general population.

Prevalence of radiographic small lung opacities and pleural abnormalities in a representative adult population sample.

The prevalence of radiographic widespread small lung opacities and pleural abnormalities in the general population was assessed as part of the Mini-Finland Health Survey, which was based on a representative sample of people aged 30 years or over. Full-size chest radiographs of 7,095 persons (89% of the sample) were classified. Two radiologists classified all the radiographs according to the ILO 1980 Classification of Radiographs of Pneumoconioses. Small lung opacities and pleural abnormalities were considerably more prevalent in the older age groups and in men. Small lung opacities on the radiographs and pleural abnormalities were associated with work in industrial occupations, particularly in men. There was a clear association between small lung opacities and pleural abnormalities. The sex differences may be related to occupational factors, particularly dust exposure. The elevated risk of pleural plaques in persons with small lung opacities on the radiographs may indicate a fiber effect.

Seven-year follow-up of white-finger symptoms and radiographic wrist findings in lumberjacks and referents.

OBJECTIVES: In 1978, a cross-sectional study of 279 lumberjacks exposed to hand-arm vibration and 178 unexposed referents was conducted. The aim of the present study was to provide a seven-year follow-up on (i) the changes in the white-finger symptoms among the lumberjacks and the referents, (ii) the effect of white-finger symptoms on the professional prognosis of the lumberjacks, and (iii) the relationship between hand-arm vibration and changes in wrist bones. METHODS: The methods consisted of a questionnaire, a routine clinical examination, and radiographs of the wrists and hands. The examinations were conducted as a field study using a mobile unit. RESULTS: The prevalence of white-finger symptoms was 18% among the lumberjacks and 3% among the referents in the original study. Seven years later 213 lumberjacks and 140 referents participated in the follow-up. The prevalence of white-finger symptoms was 24.9 among the lumberjacks and 5.7 among the referents, and the seven-year cumulative incidence was 14.7% among the lumberjacks and 2.3% among the referents. After allowance for age, there was no difference in the incidence of white-finger symptoms between the lumberjacks with fewer than 15 years of exposure and the referents, but the risk increased with increasing duration of exposure (risk ratio 8.9, 95% confidence interval 2.5-28.9 for those exposed at least 25 years). There was no difference between the two groups in the prevalence of radiographically detectable translucencies or osteoarthrotic changes in the wrists and hands. CONCLUSION: According to the results, white-finger symptoms are still a problem among lumberjacks who started chain-saw work before 1970.