中文摘要：

目的探讨苯暴露对工人血常规指标的影响，并以3．25mg／m^3（1ppm）、0．325mg／m^3（0．1ppm）为界值探讨不同范围的苯暴露对各血常规指标的影响。方法在PubMed、Scopus、SinoMed、中国知网、万方、维普等数据库检索2016年5月1日之前发表的关于苯作业人群苯暴露及其血常规指标计数情况的文献，采用随机和固定效应模型，计算合并标准均数差（SMD）及其95％可信区间（95％C1），同时根据苯暴露浓度对数据进行亚组分析。结果本次研究共纳入30篇符合标准的文献。meta分析结果表明，苯暴露工人白细胞、红细胞、血小板、中性粒细胞、淋巴细胞、血红蛋白等血常规指标计数与对照组相比明显降低。进一步的亚组分析发现，当苯暴露浓度高于3．25mg／m^3时，白细胞、红细胞、血小板、中性粒细胞、淋巴细胞、血红蛋白等6项血常规指标计数明显下降；当苯暴露浓度在0．325～3．25mg／m^3时，白细胞、血小板、血红蛋白等3项血常规指标计数明显下降；当苯暴露浓度低于0．325mg／m^3时，仅红细胞计数明显下降，差异均有统计学意义（P〈O．05）。结论职业苯暴露与工人多个血常规指标的异常有关，即使在低于3．25mg／m^3的暴露浓度下，苯暴露也具有血液毒性；白细胞、血小板、血红蛋白等指标对低浓度苯暴露的毒性效应更敏感。

英文摘要：

Objective To assess the effect of occupational benzene exposure on the blood routine indexes, especially under the condition of low doses （0.325-3.25 mg/m^3, 〈0.325 mg/m^3）. Methods The original articles on benzene exposure and blood routine indexes published before May 1, 2016 were collected from the PubMed, Scopus, SinoMed, CNKI, WANFANG DATA and VIP database. Both fixed-effects model and random-effects model were used to analyze benzene exposure and blood routine indexes. Subgroup analysis by exposure concentration was also performed. Results In the analysis, thirty papers were included. The meta-analysis showed that exposure to benzene could make WBC, RBC, PLT, Neu, Lym, HGB declined. The subgroup analysis showed that when benzene exposure concentration was higher than 3.25 mg/m^3, six blood routine indexes were significantly different between exposure and control groups, they were WBC, RBC, PLT, Neu, Lym and HGB. When benzene exposure concentration was between 0.325 and 3.25 mg/m^3, three types of cell counts including WBC, PLT and HGB were significantly different between exposure and control groups. When benzene exposure concentration was lower than 0.325 mg/m^3, only the RBC significantly differed between exposure and control group. Conclusion Benzene exposure leads to a decrease of blood cell counts. The hematotoxicity exists under the low dose benzene exposure （〈3.25 mg/m^3）. The low dose benzene exposure is related to the decline of WBC, PLT and HGB.