Abstract：
BACKGROUND: Manganese (Mn) is an essential micronutrient as well as a well-established neurotoxicant. Occupational and environmental exposures may bypass homeostatic regulation and lead to increased systemic Mn levels. Translocation of ultrafine ambient airborne particles via nasal neuronal pathway to olfactory bulb and tract may be an important pathway by which Mn enters the central nervous system.
OBJECTIVE: To measure olfactory tract/bulb tissue metal concentrations in Mn-exposed and non-exposed mineworkers.
METHODS: Using inductively coupled plasma-mass spectrometry (ICP-MS), we measured and compared tissue metal concentrations in unilateral olfactory tracts/bulbs of 24 Mn-exposed and 17 non-exposed South African mineworkers. We used linear regression to investigate the association between cumulative Mn exposures and olfactory tract/bulb Mn concentration.
RESULTS: The difference in mean olfactory tract/bulb Mn concentrations between Mn-exposed and non-Mn exposed mineworkers was 0.16 µg/g (95% CI -0.11, 0.42); but decreased to 0.09 µg/g (95% CI 0.004, 0.18) after exclusion of one influential observation. Olfactory tract/bulb metal concentration and cumulative Mn exposure suggested there may be a positive association; for each mg Mn/m3-year there was a 0.05 µg/g (95% CI 0.01, 0.08) greater olfactory tract/bulb Mn concentration overall, but -0.003 (95% CI -0.02, 0.02) when excluding the three influential observations. Recency of Mn exposure was not associated with olfactory tract/bulb Mn concentration.
CONCLUSIONS: Our findings suggest that Mn-exposed mineworkers might have higher olfactory tract/bulb tissue Mn concentrations than non-Mn exposed mineworkers, and that concentrations might depend more on cumulative dose than recency of exposure.
OBJECTIVE: To measure olfactory tract/bulb tissue metal concentrations in Mn-exposed and non-exposed mineworkers.
METHODS: Using inductively coupled plasma-mass spectrometry (ICP-MS), we measured and compared tissue metal concentrations in unilateral olfactory tracts/bulbs of 24 Mn-exposed and 17 non-exposed South African mineworkers. We used linear regression to investigate the association between cumulative Mn exposures and olfactory tract/bulb Mn concentration.
RESULTS: The difference in mean olfactory tract/bulb Mn concentrations between Mn-exposed and non-Mn exposed mineworkers was 0.16 µg/g (95% CI -0.11, 0.42); but decreased to 0.09 µg/g (95% CI 0.004, 0.18) after exclusion of one influential observation. Olfactory tract/bulb metal concentration and cumulative Mn exposure suggested there may be a positive association; for each mg Mn/m3-year there was a 0.05 µg/g (95% CI 0.01, 0.08) greater olfactory tract/bulb Mn concentration overall, but -0.003 (95% CI -0.02, 0.02) when excluding the three influential observations. Recency of Mn exposure was not associated with olfactory tract/bulb Mn concentration.
CONCLUSIONS: Our findings suggest that Mn-exposed mineworkers might have higher olfactory tract/bulb tissue Mn concentrations than non-Mn exposed mineworkers, and that concentrations might depend more on cumulative dose than recency of exposure.
摘要：
背景：锰（Mn）是必需的微量营养素，也是公认的神经毒物。职业和环境暴露可能会绕过稳态调节，并导致系统Mn水平升高。超细环境空气传播颗粒通过鼻神经元途径转移到嗅球和嗅束可能是Mn进入中枢神经系统的重要途径。
目的：测量暴露于锰和未暴露于锰的矿工的嗅道/灯泡组织金属浓度。
方法：使用电感耦合等离子体质谱法（ICP-MS），我们测量并比较了24名锰暴露和17名未暴露的南非矿工的单侧嗅束/球茎中的组织金属浓度。我们使用线性回归来研究累积Mn暴露与嗅道/鳞茎Mn浓度之间的关联。
结果：接触锰和未接触锰的矿工之间的平均嗅道/鳞茎锰浓度差异为0.16µg/g（95％CI-0.11，0.42）；但在排除一项有影响的观察后下降至0.09µg/g（95％CI0.004，0.18）。嗅束/灯泡金属浓度和累积锰暴露表明可能存在正相关；每mg锰/m3年，嗅束/灯泡锰浓度总体上增加0.05µg/g（95％CI0.01，0.08），但-0.003（95%CI-0.02，0.02）时排除三个有影响的观察。Mn暴露的新近程度与嗅道/鳞茎Mn浓度无关。
结论：我们的研究结果表明，接触锰的矿工可能比未接触锰的矿工具有更高的嗅道/鳞茎组织锰浓度，浓度可能更多地取决于累积剂量，而不是暴露的最近时间。
目的：测量暴露于锰和未暴露于锰的矿工的嗅道/灯泡组织金属浓度。
方法：使用电感耦合等离子体质谱法（ICP-MS），我们测量并比较了24名锰暴露和17名未暴露的南非矿工的单侧嗅束/球茎中的组织金属浓度。我们使用线性回归来研究累积Mn暴露与嗅道/鳞茎Mn浓度之间的关联。
结果：接触锰和未接触锰的矿工之间的平均嗅道/鳞茎锰浓度差异为0.16µg/g（95％CI-0.11，0.42）；但在排除一项有影响的观察后下降至0.09µg/g（95％CI0.004，0.18）。嗅束/灯泡金属浓度和累积锰暴露表明可能存在正相关；每mg锰/m3年，嗅束/灯泡锰浓度总体上增加0.05µg/g（95％CI0.01，0.08），但-0.003（95%CI-0.02，0.02）时排除三个有影响的观察。Mn暴露的新近程度与嗅道/鳞茎Mn浓度无关。
结论：我们的研究结果表明，接触锰的矿工可能比未接触锰的矿工具有更高的嗅道/鳞茎组织锰浓度，浓度可能更多地取决于累积剂量，而不是暴露的最近时间。
