| Autor: |
Robert B. Reger, John F. Gamble, Robert E Glenn |
| Rok vydání: |
2012 |
| Předmět: |
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| Zdroj: |
Journal of Clinical Toxicology. |
| ISSN: |
2161-0495 |
| DOI: |
10.4172/2161-0495.s1-008 |
| Popis: |
Implementation of the coal mine dust (“CMD”) interim standard of 3.0 milligrams per cubic meter (“mg/m 3 ”) in 1970 was reduced to 2.0 mg/m3 in 1972 and produced a steady decline in dust levels and prevalence of coal workers pneumoconiosis (“CWP”). Beginning in the mid-1990s, an apparent increase was reported in what was thought to be severe and rapidly progressive CWP and PMF despite stability in CMD levels. These “sentinel health” events led to further investigation and stimulated the 2010 MSHA proposal to lower the current CMD standard from 2.0 mg/m 3 to 1.0 mg/m 3 . The purpose of this study is to summarize exposure-response associations between CMD and CWP to evaluate evidence for a revised standard. There are five cohorts of UK and US coalminers with exposure-response analyses useful for assessing a proposed coal mine dust standard. Two major biases confound such an evaluation. Exposure misclassification bias occurs for exposures occurring before standards and before sampling surveillance was initiated. This bias is most obvious in the US studies where sample results collected after initiation of the standard were back-extrapolated to pre-standard time periods. The bias introduced produces a spurious steeper exposure-response slope due to overestimation of risk at higher exposure levels (>4 mg/m 3 ) and under-estimation of risk at lower exposures. Participation bias occurs in one of the US studies when survey participation rates dropped below 50% in rounds 1-4. Exposure-response evidence suggests a coal mine dust standard of 2 mg/m 3 appears to be protective from occurrence of CWP ≥2 for low rank coals. However there is excess CWP ≥2 in miners exposed to high rank coal, suggesting a lower exposure standard is needed to protect these miners. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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