Wong O, Raabe G K
Applied Health Sciences, 181 Second Avenue, Suite 628, San Mateo, California 94401, USA.
Regul Toxicol Pharmacol. 1997 Oct;26(2):188-99. doi: 10.1006/rtph.1997.1162.
Case reports have suggested an association between benzene exposure and multiple myeloma. Because petroleum workers are exposed to benzene or benzene-containing liquids, studies of these workers provide an opportunity for investigating the relationship between benzene and multiple myeloma. A large number of cohort studies of petroleum workers have been conducted. However, few of them have reported results of multiple myeloma separately. One reason is that multiple myeloma is usually grouped with other lymphopoietic cancers in the analysis. Another reason is that multiple myeloma is relatively rare, and few individual studies are large enough to provide reliable risk estimates. To determine the risk of multiple myeloma in petroleum (refinery, distribution, production, and pipeline) workers, we have identified 22 cohort mortality studies of petroleum workers in the United States, the United Kingdom, Canada, and Australia. Authors of these studies were contacted, and data on the number of observed deaths and age-specific person-years of observation were requested. Data from individual studies were combined in a pooled analysis (meta-analysis). In addition to the pooled analyses, results for individual cohorts, most of which have never been reported before, are also presented. The combined multinational cohort consisted of more than 250,000 petroleum workers, and the observation period covered an interval of 55 years from 1937 to 1991. A total of 205 deaths from multiple myeloma were observed, compared to 220.93 expected, a total derived from respective national mortality rates. The corresponding standardized mortality ratio (SMR) was 0.93 and the 95% confidence interval (95% CI) was 0.81-1.07. Additional analyses were performed by type of facility and industrial process. Stratum-specific SMRs (95% CIs) were 0.92 (0.77-1.09) for refinery workers and 0.93 (0.69-1.23) for distribution workers. When individual cohorts were stratified by length of observation, no pattern was detected. The pooled analysis indicates that petroleum workers are not at an increased risk of multiple myeloma as a result of their exposure to benzene, benzene-containing liquids, or other petroleum products in their work environment. This conclusion is supported by cohort studies of workers in other industries who were exposed to benzene as well as by population-based case-control studies of multiple myeloma and occupational exposures.
病例报告表明苯暴露与多发性骨髓瘤之间存在关联。由于石油工人会接触苯或含苯液体，对这些工人的研究为调查苯与多发性骨髓瘤之间的关系提供了契机。已经开展了大量针对石油工人的队列研究。然而，其中很少有研究单独报告多发性骨髓瘤的结果。一个原因是在分析中多发性骨髓瘤通常与其他淋巴造血系统癌症归为一组。另一个原因是多发性骨髓瘤相对罕见，很少有个别研究规模大到足以提供可靠的风险估计。为了确定石油（炼油、分销、生产和管道）工人患多发性骨髓瘤的风险，我们识别了美国、英国、加拿大和澳大利亚的22项石油工人群体死亡率研究。我们联系了这些研究的作者，并索要了观察到的死亡人数以及按年龄划分的观察人年数的数据。来自各个研究的数据被合并进行汇总分析（荟萃分析）。除了汇总分析外，还呈现了各个队列的结果，其中大多数此前从未报告过。合并后的跨国队列由超过25万名石油工人组成，观察期涵盖了从1937年到1991年的55年。共观察到205例死于多发性骨髓瘤，而根据各国死亡率得出的预期死亡数为220.93例。相应的标准化死亡比（SMR）为0.93，95%置信区间（95%CI）为0.81 - 1.07。还按设施类型和工业流程进行了额外分析。炼油工人的分层特异性SMR（95%CI）为0.92（0.77 - 1.09），分销工人的为0.93（0.69 - 1.23）。当按观察时长对各个队列进行分层时，未发现任何模式。汇总分析表明，石油工人不会因其在工作环境中接触苯、含苯液体或其他石油产品而增加患多发性骨髓瘤的风险。其他接触苯的行业工人的队列研究以及基于人群的多发性骨髓瘤与职业暴露病例对照研究也支持这一结论。
