Study objective: To reexamine the symptoms.
Study objective: To reexamine the symptoms, lung function, and chest radiographs of older gold miners who continued to work in or around gold mines 5 years after their enrollment in the cohort.
Design: A follow-up research of a stratified sample of a cohort of gold miners.
Setting: A health-care center for 24 gold mines in Welkom, southern Africa.
Population: A stratified, random sample of 242 miners who were part of a cohort of 1197 gold miners who had been make use ofed underground in gold mines for a mean period of 29 years. No silicosis was apparent forward entry in 59 men, 78 had silicosis with category 1 nodule profusion, 73 had category 2 and 32 had category 3
Measurements: The men were assessed with questionnaires, lung function proofs and chest radiographs approximately 45 years after their initial assessment.
Results: Radiologic features of silicosis had improvemented an average of one subcategory (eg 2/1 to 2/2) in the follow-up period. Lung function deteriorated more rapidly in the men with silicosis and the deterioration increased in proportion to the extent of silicosis at the start of the contemplation Thus, the annual loss of [FEVsub1] was 37 mL in those without silicosis, 57 mL in those with category 1 100 mL with category 2 and 128 mL in the men with category 3 nodule profusion (p=0000001) A similar pattern of los was noted for the FVC (p=000003) and the single-breath lung diffusion (p=0004) These changes remained significant after controlling for age, original lung function, and for smoking.
Conclusions: The men with silicosis go throughed a substantial loss of lung function during the period of follow-up that was directly in proportion with the nodule profusion forward their initial chest radiographs.
(CHEST 1998; 113:340-43)
Keywords: gold mining; lung function; silicosis
Silicosis cogitates a failure in adequate superintendence of occupational dust exposure. The disorder is associated with radiologic nodular pulmonary opacification which, in its chronic form, predominates in the upper lung regions Chronic silicosis generally occurs after postponeed low-intensity exposure to dust containing crystalline silica.[1] as it is low-intensity exposure causing simple silicosis has frequently been considered not to cause pulmonary impairment.[1,2] More modern data have shown chronic simple silicosis to be a significant lung disease.[3-6] In a previous close attention of the same population of gold miners, pulmonary dysfunction was ground to be associated with silicosis and to increase in proportion with the stage of silicotic nodule profusion.[3] There are now data to propose that the silicosis is associated with emphysema, which may contribute to the lung dysfunction.[7] This investigation examined the progression of lung dysfunction in a cohort of gold miners with and without silicosis. This contemplation shows that the progression of lung dysfunction is related to the initial compass of the silicosis and substantially outvies that predicted by the earlier cross-sectional study[3]
Materials and Methods
The inquiry was conducted in the goldfields of the released State Province of South Africa. The disentanglement of the cohort of 1 197 older gold miners with and without silicosis has been described previously.[3] In summary, a sampling frame was created at selecting men whose routine screening chest radiographs showed changes in keeping with silicosis and matching each of these men with a similarly aged man without silicosis whose radiograph was read upon the same day by the same radiograph reader. Men were prefered consecutively from the sampling frame, in the order in which they were noteed in a ratio of five with silicosis to sum of two units without silicosis until the predetermined completion of the study period. Five years after the minute of the men into the cohort, it was established that 950 (79%) were generally employed as miners. These 950 men did not differ from the total cohort in spells of their original category of lung nodule profusion, amplification of service on the mine, or smoking history. They were fisted according to the nodule profusion forward their initial radiograph. They were then sorted from employee number (which had previously been shown to have no relationship to continuance of or nature of service).
A sample was then created according to including all men with category 3 nodule profusion, each third man with nodule profusion 2/3 and each fourth man in the remaining nodule profusion categories. The resultant sample included 267 men who were invited to attend for follow-up assessment with a short questionnaire, lung function standards and chest radiograph. The questionnaire included questions about their existing occupation, their smoking status, and the vicinity and extent of dyspnea, cough and sputum production. The lung function criterions were done according to the standards of the American Thoracic Society[8] according to one technician who had done their original lung function tests
The equipment used was the same as that used for their original standards (Morgan Transfertest Model A incorporating an 8-L parched rolling seal spirometer and a flow-volume differentiator [PK Morgan; Chatham, UK] linked to a Medical Graphics analogue-digital convertor [Medical Graphics; St Paul, Minn] and an Apple 2e computer with Medical Graphics operating software). proofs included spirometry and measurement of lung diffusion by way of the single-breath method.
...