Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Wilson SE[original query] |
---|
Occupational exposure to respirable crystalline silica among US metal and nonmetal miners, 2000-2019
Misra S , Sussell AL , Wilson SE , Poplin GS . Am J Ind Med 2023 66 (3) 199-212 BACKGROUND: In metal and nonmetal (M/NM) mines in the United States, respirable crystalline silica (RCS) exposures are a recognized health hazard and a leading indicator of respiratory disease. This study describes hazardous exposures that exceed occupational exposure limits and examines patterns of hazardous RCS exposure over time among M/NM miners to better inform the need for interventions. METHODS: Data for this study were obtained from the Mine Safety and Health Administration (MSHA) Open Government Initiative Portal for the years 2000-2019, examining respirable dust samples with MSHA-measured quartz concentration >1%. Descriptive statistics for RCS were analyzed for M/NM miners by year, mine type, sector, commodity, occupation, and location in a mine. RESULTS: This study found the overall geometric mean (GM) for personal exposures to RCS was 28.9 μg/m(3) (geometric standard deviation: 2.5). Exposures varied significantly by year, mine type, sector, commodity, occupation, and location in a mine. Overall, the percentages of exposures above the MSHA permissible exposure limit (PEL for respirable dust with >1% quartz, approximately 100 μg/m(3) RCS) and the National Institute for Occupational Safety and Health RCS recommended exposure limit (REL, 50 μg/m(3) ) were 11.8% and 27.3%, respectively. GM exposures to RCS in 2018 (45.9 μg/m(3) ) and 2019 (52.9 μg/m(3) ) were significantly higher than the GM for all years prior. The overall 95th percentile of RCS exposures from 2000 to 2019 was 148.9 μg/m(3) , suggesting a substantial risk of hazardous exposures above the PEL and REL during the entire period analyzed. CONCLUSIONS: The prevalence of high exposures to RCS among M/NM miners continues in the past 20 years and may be increasing in certain settings and occupations. Further research and intervention of the highest exposures are needed to minimize the risks of acquiring silica-induced respiratory diseases. |
Lumbar position sense with extreme lumbar angle
Maduri A , Wilson SE . J Electromyogr Kinesiol 2009 19 (4) 607-13 Tasks involving flexed torso postures have a high incidence of low back injuries. Changes in the ability to sense and adequately control low back motion may play a role in these injuries. Previous studies examining position sense errors of the lumbar spine with torso flexion found significant increases in error with flexion. However, there has been little research on the effect of lumbar angle. In this study, the aim of the study was to examine how position sense errors would change with torso flexion as a function of the target lumbar angle. Fifteen healthy volunteers were asked to assume three different lumbar angles (maximum, minimum and mid-range) at three different torso flexion angles. A reposition sense protocol was used to determine a subject's ability to reproduce the target lumbar angles. Reposition sense error was found to increase 69% with increased torso flexion for mid-range target curvatures. With increasing torso flexion, the increase in reposition sense errors suggests a reduction in sensation and control in the lumbar spine that may increase risk of injury. However, the reposition error was smaller at high torso flexion angles in the extreme target curvatures. Higher sensory feedback at extreme lumbar angles would be important in preventing over-extension or over-flexion. These results suggest that proprioceptive elements in structures engaged at limits (such as the ligaments and facet joints), may provide a role in sensing position at extreme lumbar angles. Sensory elements in the muscles crossing the joint may also provide increased feedback at the edges of the range of motion. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 13, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure