The evidence surveyed suggests that chronic levels of silica dust that do not . Emphysema type in relation to silica dust exposure in South African gold miners. Occupational exposure is an important risk factor for chronic obstructive pulmonary disease (COPD), and silica dust is one of the most important. In , million United States adults were estimated to have COPD. However Silicosis usually takes at least 10 years after exposure to develop. However.
More recently, for both epidemiological and clinical purposes, the definition of COPD has moved to one that is based almost entirely on spirometric measurements of FEV1 and FVC made after the use of a short-acting, bronchodilating inhaler. This shift has had profound implications.
The use of fixed cut-offs has been criticized as being arithmetically inept because the variability of lung function measurements is not proportional to their predicted values based on an individual's age, sex and height. The former have the advantage, when at their best, of sufficiently large numbers and detailed information on exposure to workplace agents and important confounders. Perhaps more even than in most occupational studies, longitudinal data are preferable because they allow the prospective identification of exposed workers who have accelerated declines in lung function irrespective of where their measurements are in relation to normal ranges see above.
In practice, the majority of such studies have been cross-sectional in design and so open to concerns over cause and effect arising, for example, from healthy worker effects. Studies based in general populations have been of two sorts: The first, and most cited, systematic review 14 is replete with references to this index, as is its successor 15 in which the term is used 52 times.
While not wishing to diminish any important public health message, it is worth noting that the value of PAR estimates lies in those that relate to exposures that are definitively causal and are thus, conceptually, amenable to prevention; as will be seen later, a second striking feature of the relevant literature is its relatively uncritical approach to the distinction between association and cause.
It is not possible, in the space of this review, to discuss in any detail the extensive, industry-based literature but a summary of the areas of agreement is provided below with a discussion of areas that would benefit from further research. More attention will be paid to studies of occupational COPD in general populations, particularly those focused on non-specific exposures to irritant agents in workplace air.
Here, despite a large number of published studies, there is considerable remaining uncertainty and a detailed discussion of the areas of doubt is provided. The sources of data are largely drawn from previous reviews with supplementary material that was either not included in them or has been published subsequently. Studies of particular workforces or exposures: It is well reviewed elsewhere 1617 and, usefully, by a recent, Danish collective 18 that focused on studies that used spirometry in their outcome definitions.
Although a very wide variety of occupations have been studied in this way, for most the number of relevant studies is limited and the evidence remains inconclusive. Coal mining is one exception. Here the numbers available for study tend to be large and advantage can be taken of the routine pulmonary surveillance offered in many countries.
It is estimated that between 15 and 30 percent of asthmatics have new-onset adult asthma or work-exacerbated asthma. Thus, over two million workers in the United States suffer from work-related asthma. Chronic obstructive pulmonary disease COPD Chronic obstructive pulmonary disease refers to chronic bronchitis, emphysema, and combined presentations of these two diseases. Chronic obstructive pulmonary disease is a leading cause of morbidity and mortality in the United States and world-wide.
However, close to 24 million adults were estimated to have impaired lung function, suggesting under-diagnosis of COPD. Although often thought of as a disease caused by cigarette smoking, it is well-recognized that COPD is also caused by occupational exposures. Coal mine dust and crystalline silica encountered in industries such as mining and construction are known risks.
A study of participants in the Third National Health and Nutrition Examination Survey found increased risk for COPD in a number of industries including rubber, plastics, and leather manufacturing; utilities; building services; textile manufacturing; and construction. CWP usually develops slowly, taking 10 years or more from initial exposure to onset of disease. It causes changes in the chest radiograph and, in more serious cases, can cause shortness of breath, loss of pulmonary function, and even death.
Enactment was followed by a marked reduction in the prevalence of CWP in long-term coal miners. In addition, advanced cases have recently been detected in miners in their 30s and 40s. Especially in view of the increasing use of coal as an energy source and the predicted growth of coal mining, protecting coal miners from respiratory disease continues to be an important and ongoing priority.
Chronic obstructive pulmonary disease and occupational exposure to silica.
Silica Silica, also known as silicon dioxide, is the most common mineral on earth. Inhaling dusts that contain crystalline forms of silica can cause a fibrosing interstitial lung disease called silicosis. Silicosis usually takes at least 10 years after exposure to develop.COPD I Nucleus Health
However, it can develop more quickly, especially after large exposures. Quartz is a common type of crystalline silica and is a large component of many types of rock. Inhalation exposure can occur in many kinds of work, including tunneling, quarrying, mining, construction, roadway repair and demolition, sandblasting or any type of work that breaks up quartz-containing rock.
Cristobalite exposure can occur in foundry work as a result of heating amorphous silica. In addition to causing silicosis, crystalline silica exposure has been associated with pulmonary function impairment and COPD. Crystalline silica is thought to damage lung tissue in large part as a result of oxidant mechanisms, with freshly fractured crystalline silica is being more potent than aged materials.
Silica-induced diseases can be prevented by reducing exposures. It is encouraging that deaths from silicosis have fallen from more than in to less than in Asbestos Asbestos is a commercial term that refers to six types of fibrous minerals, including one serpentine chrysotile and five amphiboles [crocidolite riebeckite asbestosamosite cummingtonite-grunerite asbestosanthophyllite asbestos, tremolite asbestos, and actinolite asbestos].
Asbestos mineral fibers are flame and heat resistant, pliable, strong, refractory to corrosive chemicals, and provide insulation. Because of its ability to insulate from heat and protect against fire, asbestos has been widely used as a building material. It has been especially important in the shipbuilding industry.
Chronic obstructive pulmonary disease and occupational exposure to silica.
It has also been woven into fabric to make fireproof, protective textile products, such as fireproof blankets and suits, It has been used as a brake liner e. Although known and used for its fire resistant properties as early as B.
Although its use in the US has largely disappeared, exposure continues to occur due to renovation or demolition of existing building stock or through exposure to asbestos-containing products such as brake linings or asbestos-containing cement products that continue to be imported. Inhalation of asbestos fibers can have many adverse health effects. Because these develop slowly, usually presenting a decade or more after exposure, asbestos-caused diseases remain an important problem.
Asbestos fibers can cause asbestosis, a fibrosing interstitial lung disease. They can also penetrate through the lung tissue to the pleura, which are the tissues lining the lungs and chest cavity. In the pleura, they can cause conditions including pleural effusions fluid collectionspleural plaques, and diffuse pleural fibrosis. Asbestos fibers are also a cause of lung cancer. Risk increases multiplicatively if an exposed person also smokes.
Another much-feared type of cancer caused by asbestos is mesothelioma, which arises in the pleura or peritoneum lining of the abdominal cavity.
CDC - NIOSH Program Portfolio : Respiratory Diseases : Risks
Mesothelioma usually cannot be cured and thus has a high fatality rate. Flock FlockCdc-pdf consists of short fibers that are cut from long filaments and glued to backing material such as cloth to provide a fuzzy, carpet-like surface texture. They are usually prepared from synthetic materials such as nylon, rayon, or polypropylene.