Characterization of manganese exposure biomarkers among welder apprentices

描述(由申请人提供)：尽管有证据表明接触焊接烟雾，特别是接触锰(Mn)会对健康造成不利影响，但暴露的生物标记物知之甚少，也没有在纵向设计中进行彻底的评估。这项研究旨在评估特征良好的吸入性锰暴露与锰暴露的一些短期和长期生物标志物之间的关系。我们将招募一个由80名焊工学徒组成的队列，在四周的密集暴露后，以及在暴露停止后的四周，对队列成员中空气中的锰浓度和锰暴露的生物标志物进行密集评估。在暴露期间，每名参与者每周两次测量个人暴露在空气中的锰和焊接烟尘的其他成分。此外，还将评估锰的粒度分布和焊接烟尘总颗粒物，以确定其对暴露生物标志物的影响。所有受试者要评估的短期暴露生物标志物是血锰和尿锰。将在20名受试者中评估的长期暴露生物标记物是头发中的锰和脑组织中锰浓度的两个测量指标，即通过磁共振成像(MRI)评估的Pallidal指数(PI)和T1松弛时间。生物效应的生物标志物也将在所有受试者中进行评估，以便与暴露指数进行比较。将对接受MRI评估的受试者进行临床运动功能测试(UDPRS3和普渡钉板测试)，以探索脑组织中暴露于锰的生物标记物与运动任务表现之间的关系。有可能影响空气和生物标志物浓度之间关系的个人特征，包括饮食、吸烟状况和先前存在的健康状况，将通过问卷调查在所有受试者中进行评估。我们将使用混合效应分布滞后模型来模拟空气暴露水平和暴露生物标志物之间的关系，以允许描述和测试最近和累积暴露对每个观察到的生物标志物的贡献。基于空气或生物标记物的暴露与影响的生物标记物之间的关系将被类似地建模。这些结果将为未来焊接或锰相关健康影响研究中的流行病学暴露评估提供信息，并为在各种暴露环境中解释锰生物标记物结果提供指导。 与公共健康相关：尽管有证据表明职业性接触吸入锰会对健康产生不利影响，但接触锰的生物标志物却知之甚少。这项研究将探索空气中锰浓度与锰暴露的各种生物标志物之间的关系，包括血液、尿液、头发和脑组织(通过磁共振成像进行评估)，随着时间的推移，一组学徒焊工。

DESCRIPTION (provided by applicant): Despite evidence of adverse health effects resulting from exposure to welding fume and in particular to manganese (Mn), biomarkers of exposure are poorly understood and have not been thoroughly evaluated in a longitudinal design. This study is designed to evaluate the relationship between well-characterized inhaled Mn exposure and a number of short- and long-term biomarkers of Mn exposure. We will recruit a cohort of 80 apprentice welders and intensively evaluate airborne Mn concentrations and biomarkers of Mn exposure among members of the cohort over four weeks of intensive exposure, and then again four weeks after exposure cessation. Personal airborne exposures to Mn and other components of welding fume will be measured twice weekly on each participating subject during the exposure period. In addition, the particle size distribution of Mn and total welding fume particulate will be evaluated to determine its influence on exposure biomarkers. Short-term biomarkers of exposure to be evaluated in all subjects are blood Mn and urine Mn. Long-term biomarkers of exposure which will be assessed among a subset of 20 subjects are hair Mn and two measures of Mn concentration in brain tissue, the Pallidal Index (PI) and T1 relaxation time, evaluated via magnetic resonance imaging (MRI). Biomarkers of biological effect will also be evaluated among all subjects for comparison with the exposure indices. Clinical motor function tests (UDPRS3 and Purdue Pegboard test) will be administered to subjects undergoing MRI evaluation to allow for exploration of the relationship between biomarkers of Mn exposure in brain tissue and motor task performance. Individual characteristics with the potential to influence the relationship between air and biomarker concentrations, including diet, smoking status, and pre-existing health conditions, will be assessed in all subjects via questionnaire. We will model the relationships between air exposure levels and exposure biomarkers using a mixed effects distributed lag model to allow for description and testing of the contribution of recent and cumulative exposure on each observed biomarker. Relationships between air or biomarker-based exposures and biomarkers of effect will be similarly modeled. The results will inform future epidemiological exposure assessment in studies of welding or Mn- related health effects and provide guidance on interpretation of Mn biomarker results in a variety of exposure contexts. PUBLIC HEALTH RELEVANCE: Although there is evidence that occupational exposure to inhaled manganese results in adverse health effects, biomarkers of exposure to manganese are poorly understood. This study will explore the relationships between airborne manganese concentrations and a variety of biomarkers of manganese exposure, including blood, urine, hair, and brain tissue (assessed via magnetic resonance imaging), over time in a group of apprentice welders.