【摘要】 [背景]职业铝暴露危害工人的认知功能。目前对于职业铝作业人群认知功能障碍的评估缺少脑功能影像资料。脑功能连接值在职业铝暴露引起认知功能下降中的作用尚不明确。[目的]探讨脑功能连接值在职业铝暴露引起的认知功能下降中的中介效应，探索认知损害与脑功能连接的关系，寻找合适的职业铝暴露所致早期认知变化的影像学凭证。[方法]本研究利用前期横断面调查，依据铝作业职工、40周岁以上、铝作业工龄> 1年、蒙特利尔国际认知评估（MoCA）量表（北京版）评分<26分，选择20例职工为病例组，并在同期的非铝作业职工中根据1∶2匹配原则，选择基本状况（年龄、吸烟情况、饮酒情况等）与之相符的40名健康职工为对照组。收集研究对象的基本信息，检测血浆铝水平、认知功能水平，利用磁共振成像测定默认模式网络（DMN）不同脑功能连接值。利用中介效应分析研究脑功能连接在铝暴露与认知功能关系中的作用。[结果]病例组的血浆铝浓度是对照组的1.76倍[（33.04±12.02）μg·L–1 vs (18.74±8.95)μg·L–1,P <0.05], MoCA得分比对照组低9.5分[（18.35±2.64）vs(27.85±0.92), P <0.05]。病例组DMN1、DMN2的平均功能连接值比对照组低（P <0.05），病例组左楔前叶、左中扣带回皮层、左上内侧回、左侧中央前回、左侧小脑的平均功能连接值与对照组相比也出现了下降（P <0.05）。血浆铝浓度与DMN1、MoCA量表得分呈负相关（b=–0.004,95%CI：–0.008～–0.001;b=–0.15,95%CI：–0.233～–0.067;P <0.05）,DMN1、DMN2的平均功能连接值和MoCA分数呈正相关（b=10.945,95%CI:5.574～16.316;b=10.107,95%CI:2.457～17.758;P <0.05）。随着血浆铝浓度的增加，MoCA得分降低，但当血浆铝质量浓度超过19.50μg·L–1继续增加时，MoCA得分降低幅度变缓。随着DMN1的增加，MoCA得分增加，但当DMN1功能连接值超过1.05继续增加时，MoCA得分增加幅度变缓。中介效应分析结果显示，DMN1功能连接值部分中介了血浆铝浓度与MoCA量表得分的关系，中介效应为25.80%。[结论]职业铝暴露工人认知损害与大脑静息态功能连接密切相关，血浆铝浓度与DMN1功能连接值和MoCA得分呈剂量-反应关系，并且DMN1功能连接值部分中介了血浆铝含量和MoCA得分之间的关系。脑功能连接值可作为研究慢性铝暴露引起的认知功能下降的有利影像学资料。更多还原

【Abstract】 [Background] Occupational aluminum exposure may associate with cognitive impairment in workers. At present, brain functional imaging data are not available for evaluating cognitive dysfunction in workers with occupational exposure to aluminum. The role of brain functional connectivity in cognitive decline associated with occupational aluminum exposure is not clear yet.[Objective] To explore potential mediating effect of brain functional connectivity value on cognitive decline induced by occupational aluminum exposure, to assess the relationship between cognitive impairment and brain functional connectivity, and to identify appropriate imaging evidence of early cognitive changes induced by occupational aluminum exposure.[Methods] This study used a subset data from a previous cross-sectional survey. Based on the data of aluminum-exposed workers, over 40 years old, aluminum-exposed working years > 1 year,Montreal International Cognitive Assessment(Mo CA)(Beijing version) score < 26 points, 20 workers were selected as the case group, and40 healthy workers with the same basic conditions(age, smoking, drinking, etc.) in non-aluminum production were selected as the control group with a 1∶2 matching ratio. The basic information of the subjects was collected, plasma aluminum level and cognitive function level were evaluated, and different brain functional connectivity values of default mode network(DMN) were measured by magnetic resonance imaging. The mediating effect analysis was conducted to examine the role of brain functional connectivity in the relationship between aluminum exposure and cognitive function.[Results] The plasma aluminum concentration of the case group was 1.76 times higher than that of the control group [(33.04±12.02) μg·L-1vs(18.74±8.95) μg·L-1, P < 0.05]; the Mo CA score was 9.5 points lower [(18.35±2.64) vs(27.85±0.92), P < 0.05]. The mean functional connection values of DMN1 and DMN2 in the case group were lower than those in the control group(P < 0.05). The mean functional connection values of the left precuneus, left middle cingulate cortex, left superior medial gyrus, left precentral gyrus, and left cerebellum also decreased in the case group compared with the control group(P < 0.05). Plasma aluminum concentration was negatively correlated with DMN1functional connectivity value and Mo CA scores(b=-0.004, 95%CI:-0.008–-0.001; b=-0.15, 95%CI:-0.233–-0.067; P < 0.05). The mean functional connection values of DMN1 and DMN2 were positively correlated with Mo CA scores(b=10.945, 95%CI: 5.574–16.316; b=10.107, 95%CI: 2.457–17.758; P < 0.05). With the increase of plasma aluminum concentration, Mo CA score decreased, but when the plasma aluminum concentration exceeded 19.50 μg·L-1, Mo CA score decreased slowly. With the increase of the mean functional connectivity value of DMN1, Mo CA score increased, but when the mean functional connectivity value of DMN1 exceeded 1.05 and continued to increase,the increase of Mo CA score slowed down. The results of mediating effect analysis showed that the functional connectivity value of DMN1 partially mediated the relationship between plasma aluminum concentration and Mo CA score, and the mediating effect was25.80%.[Conclusion] Cognitive impairment in occupational aluminum-exposed workers is closely related to brain resting-state functional connectivity. There is a dose-response relationship of plasma aluminum concentration with DMN1 functional connectivity value and Mo CA scores, and DMN1 functional connectivity value partially mediates the relationship between plasma aluminum concentration and Mo CA scores. The brain functional connectivity value can be used as meaningful imaging data to study the cognitive decline induced by chronic aluminum exposure.更多还原