Abnormalities In Workers Research Articles

Humoral immunologic abnormalities in workers exposed to asbestos cement dust

Serum specimens from 144 workers exposed to asbestos cement dust were examined for the presence of ANA, RF, immunoglobulins, and IC. These immunologic findings were compared with chest radiographic changes. A high percentage of workers had polyclonal hypergammaglobulinemia, and there was a statistically significant association between elevated levels of IgC and IgM and radiographic classification. Although a significant number of workers had an increased prevalence of ANA and elevated levels of IC, there was no correlation between these parameters and chest radiographs. These findings support B cell hyperactivity in workers exposed to asbestos and suggest that autoantibody production and IC are not directly involved in disease pathogenesis.

RISK OF ASBESTOSIS IN CROCIDOLITE AND AMOSITE MINES IN SOUTH AFRICA*

X-rays of all while and mixed-race men employed in crocidolite and amosite mines and mills were read independently by three experienced readers according to the ILO U/C classification. Abnormality was regarded as present if reported by two or more readers. Parenchymal abnormality, defined as the presence of small irregular opacities of profusion 1/0 or greater, was found in 7.3% of the workers. Pleural thickening was found in 4.5% of the workers, costophrenic angle obliteration in 3.2%, and pleural calcification in 1.7%. The prevalences of both pleural and parenchymal abnormality were strongly related to the duration of exposure to asbestos at work. The overall prevalence of abnormality increase from 4.0% in men with exposure for 1 year or less to 47.9% in men with more than 15 years of exposure. After taking into account the effects of age and duration of asbestos exposure, the prevalence of pleural abnormality was not predicted by fiber concentration. However, white men working with amosite tended to develop a higher prevalence of pleural abnormality than did those working with crocidolite. Compared to whites, men of mixed race, who only work with crocidolite, had a high prevalence of pleural abnormality in each exposure duration category. In contrast to pleural abnormality, the prevalence of parenchymal abnormality, after taking into account the effects of age and duration of exposure, was significantly predicted by fiber concentration but not by race or asbestos type. Our results suggest that parenchymal abnormality in workers in South African asbestos mines could be largely prevented by reducing exposure to fibers visible under the light microscope. However, this may not be the case for pleural abnormality.

Biochemical abnormalities in workers exposed to molybdenum dust.

Exposure to molybdenum in dust was measured in a molybdenite roasting plant. This exposure was accompanied by large elevations of serum ceruloplasmin and smaller increases in mean serum uric acid levels in the workers. Absorption of molybdenum from the dust was demonstrated by increases in plasma and urinary molybdenum levels. It remains necessary to demonstrate whether such exposure results in long-term health effects.

Respiratory abnormalities in workers exposed to grain dust.

Survey of 68 grain elevator agents in Southern Manitoba disclosed that 75% had respiratory symptoms. Chronic cough and sputum, and dyspnea associated with exposure to grain dust were common. These symptoms were reported in more than half of the smokers and ex-smokers and in more than one quarter of the nonsmokers. Twenty-seven percent of the subjects also developed systemic symptoms of “grain fever” after exposure to grain dust. Lung function tests demonstrated abnormal spirometric results in 37%, while estimation of the “closing volume” demonstrated abnormality in 42.5% of the subjects, even after the values have been standardized for smoking habit. The high prevalence of respiratory symptoms and abnormal lung function among these subjects indicated that exposure to grain dust was an important etiologic factor in their development. Hypersensitivity to grain dust was found in eight subjects by prick skin testing and in six subjects by precipitin test. There was no significant correlation between the prese...