职业铝暴露对工人认知功能影响的因子分析

Effects of occupational aluminum exposure on workers' cognitive function: Based on factor analysis

  • 摘要:
    背景 职业铝暴露可以引起工人出现明显的认知功能障碍,而认知功能障碍可涉及记忆、学习、语言、执行、视空间等多个方面。由于各研究采用的认知评价量表不同,且量表指标间存在相关性,导致研究得到的结果不能直接进行比较,未能明确职业铝暴露对机体认知功能损害的主要领域。
    目的 利用因子分析的方法探究职业铝暴露影响工人认知功能的主要领域。
    方法 采用整群抽样的方法于2014年在山西省某大型铝厂选取1 304名铝电解作业工人及检修车间工人作为研究对象。采集研究对象的空腹肘静脉血10mL,其中2mL全血提取血浆,利用电感耦合等离子体质谱法(ICP-MS)测定血浆铝含量,根据三分位法将研究对象分为低、中、高暴露组(分别以Q1、Q2、Q3组表示);采用研究组自行设计的职业流行病学调查问卷收集研究对象的一般情况资料,包括年龄、性别、婚姻状况、教育水平、职业史、疾病史和生活习惯等;采用组合问卷进行认知功能测试,包括简易精神状态量表、画钟测验、数字广度测试、物体记忆测验、言语流畅性测验、简单反应时测试。运用因子分析从16个原始指标中提取6个公共因子代替原始指标,采用方差分析比较公共因子得分差异,采用多重线性回归分析血浆铝浓度与认知功能之间的关系。
    结果 研究对象均为男性,年龄为20~56岁,血浆铝中位数(P25P75)为26.3(11.8,50.7)μg/L。Q1、Q2、Q3组的血浆铝浓度范围分别为 < 16.21、16.21~40.83和≥ 40.83 μg/L。三组在年龄、文化程度、婚姻状况、吸烟、饮酒等方面均不存在统计学差异(P>0.05)。从原始认知功能观察指标中提取6个公共因子,公共因子1~6分别为注意力、长延时记忆力、反应能力、执行功能、短延时记忆力、即刻记忆力。方差分析结果显示仅公共因子4得分在三组间的差异有统计学意义(P < 0.05)。多重线性回归结果显示:当血铝浓度作为分类变量时,在Q3组中,公共因子1和4的得分与血铝浓度呈负相关(b分别为-0.136和-0.180,P < 0.05),与Q1组相比,公共因子1和4得分分别下降12.7%、16.5%;当血铝浓度作为连续变量时,趋势检验显示血铝浓度与公共因子1和4的得分存在剂量-效应关系(t=-2.15、-2.67,P < 0.05)。
    结论 职业铝暴露会损害工人的认知能力,主要影响注意力和执行功能。

     

    Abstract:
    Background Occupational aluminum exposure can cause significant cognitive impairment in workers, which involves memory, learning, language, execution, and visual space. The results from different studies cannot be directly compared due to different cognitive evaluation scales used and correlated scale indicators. Therefore, the main cognitive areas damaged by occupational aluminum exposure have not been identified.
    Objective This study deploys a factor analysis to explore the main cognitive areas of workers affected by occupational aluminum exposure.
    Methods In 2014, a total of 1 304 aluminum electrolysis workers and maintenance workers were selected from a large aluminum plant in Shanxi Province by cluster sampling method. Fasting elbow venous blood (10 mL) of the study subjects was collected, of which 2 mL was extracted for the determination of plasma aluminum by inductively coupled plasma mass spectrometry (ICP-MS). According to tertiles of blood aluminum concentration, the subjects were divided into low, medium, and high exposure groups (Q1, Q2, and Q3 groups, respectively). A self-designed epidemiological questionnaire was used to collect general information of the subjects, including age, gender, marital status, education level, occupational history, disease history, and living habits. A combined questionnaire set was used for cognitive function tests, including Mini-mental State Examination, Clock-drawing Test, Digitspan Test, Fuld Object Memory Evaluation, Verbal Fluency Test, and Simple Reaction Time. Factor analysis was conducted to extract common factors from 16 original indicators to represent the original indicators, variance analysis was used to compare differences in common factor scores, and multiple linear regression was used to analyze the relationship between blood aluminum concentration and cognitive function.
    Results All the study subjects were male, aged 20-56 years, and their median (P25, P75) blood aluminum concentration was 26.3 (11.8, 50.7)μg/L. The blood aluminum concentration ranges in the Q1, Q2, and Q3 groups were < 16.21, 16.21-40.83, and ≥ 40.83μg/L, respectively. There was no statistical difference in age, education, marital status, smoking, and drinking among the three groups (P>0.05). Common factors 1-6 were extracted from the original cognitive function indicators, and represented attention, long delay memory, reaction ability, execution function, short delay memory, and immediate memory, respectively. The variance analysis results showed that only the score of common factor 4 was significantly different among the three groups (P < 0.05). The multiple linear regression results showed that when blood aluminum concentration was used as a categorical variable, there were negative correlations between blood aluminum concentration and the scores of common factors 1 and 4 in the Q3 group (b=-0.136 and -0.180, respectively, P < 0.05), and compared with the Q1 group, the scores of common factors 1 and 4 decreased by 12.7% and 16.5%, respectively; when blood aluminum concentration was used as a continuous variable, the trend test results showed that there were dose-effect relationships between blood aluminum concentration and the scores of common factors 1 and 4 (t=-2.15 and -2.67, P < 0.05).
    Conclusion Occupational exposure to aluminum can impair the cognitive function of workers, mainly affecting attention and executive function.

     

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