Epidemiology

For coal workers' pneumoconiosis, deaths have decreased in the US since the early 2000s.[1]​ The number of deaths recorded in 1999 was 1002, compared to 305 in 2018.[1] In the UK, data published by the Health and Safety Executive (HSE) indicate that there are an average of 130 deaths per year from coal workers' pneumoconiosis.[2]​ In terms of prevalence, a general downward trend has been observed, with the pooled prevalence in China, Europe and the US declining from 6.0% to 2.3% between the 1980s and 2010s.[3]​ However, a small resurgence in prevalence has been observed since the late 2010s in major coal-producing countries such as the US and Australia.[4][5][6]

​Silicosis mortality has also continued to decrease in the US, with 185 deaths recorded in 1999 compared to 87 in 2018.[1]​ In the UK, HSE data show that there are an average of 12 deaths per year from silicosis.[2]​ Globally, mortality from silicosis is decreasing, although a rise in prevalence has been observed in countries such as China and India.[7][8][9]​​ Mortality is not a good measure of the burden of silicosis, as the occurrence of the disease is much more common than its recording on a death certificate. In the US, an estimated 3260 to 7105 individuals are hospitalised with silicosis annually.​[10]​ New cases of silicosis continue to emerge as the result of the growth of new industries, for example engineered countertops.[11]

Beryllium sensitisation precedes chronic beryllium disease, although only around one third of cases of confirmed sensitisation will progress to disease.[12]​ Studies investigating the prevalence and mortality associated with chronic beryllium disease are limited. In the US, prevalence appears highest amongst those working at beryllium processing facilities and historically nuclear weapons production facilities, with an estimated mortality rate of 7.8%.[13][14][15]

​The general downward trend for pneumoconioses mortality is likely attributable to fewer people working in high-risk industries, as well as significant improvements in health and safety measures. Controls in the US to reduce workers' exposures were first promulgated in the early 1970s. There is a latency period of around 20 years from time of first exposure to silica or coal and the development of radiographic changes, so the diagnosis is typically seen in people who began working with silica or coal prior to the 1980s. These people are now usually >50 years old. However, a more aggressive form of silicosis (accelerated silicosis), with short duration but heavier exposure, can occur. This is also true for coal workers, where miners exposed since 1980 with only 15 to 20 years of exposure have developed pneumoconiosis. Some of these people have disease that has developed into progressive massive fibrosis.[16][17]​ There is no evidence of such a latency for chronic beryllium disease. The risk of its development is highly dependent on the presence of certain genetic polymorphisms of the human leukocyte antigen (HLA) genes, and it has occurred after low reported exposure.[18]

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