[对一家生产氯乙烯和聚氯乙烯的石化厂死亡率的重新分析]

Gennaro Valerio, Ceppi Marcello, Montanaro Fabio

Servizio di epidemiologia ambientale e biostatistica, Istituto nazionale per la ricerca sul cancro, Largo R. Benzi 10, 16132 Genova.

Epidemiol Prev. 2003 Jul-Aug;27(4):221-5.

OBJECTIVE

To study cancer mortality among main subgroups of workers employed in VC/PVC production potentially exposed to toxics and carcinogens.

MATERIALS AND METHODS

We reanalyzed the mortality of 1,658 males (follow up 1972-1995; 35,626 person years; 170 deaths) by Poisson regression, adjusting for age, age at hiring, calendar period, length of exposure and latency. We calculated the relative risks (RR) and the 95% confidence intervals (CI) for PVC baggers (n. = 197), PVC compound (n. = 403) and autoclave (n. = 209) workers. As an internal reference we used two groups of workers: technicians and employees (main reference: n. = 202 subjects), with the group of other blue collar workers (n. = 639) added for statistical purposes only (minor reference: n. = 841 subjects).

RESULTS

Pooling the four subgroups of exposed workers, the comparison with the main reference group allowed us to detect increased mortality from all causes of death (RR = 2.09; CI = 1.09-4.00; 160 deaths), all tumours (RR = 1.53; ns; 81 deaths), lung cancer (RR = 2.05; ns; 29 deaths) and cardiovascular diseases (RR = 3.57; ns; 29 deaths). The analysis for each specific subgroup revealed increased mortality from all causes of death among both PVC baggers (RR = 2.66; CI = 1.27-5.59) and PVC compound workers (RR = 2.68; CI = 1.36-5.27). Comparison of the minor reference group with the overall population of exposed workers showed increased RRs for other diseases, namely, liver tumour (RR = 4.08; ns; 9 deaths), lymphomas and leukaemia (RR = 2.97; ns; 7 deaths) and liver cirrhosis (RR = 3.30; ns; 11 deaths). The analysis for each specific subgroup revealed significantly increased RR for all tumours among PVC compound workers (RR = 1.74; CI = 1.06-2.85), for lung cancer among PVC baggers workers (RR = 3.04; CI = 1.15-7.99) and for liver cancer (RR = 9.57; CI = 1.69-54.1) and liver cirrhosis (RR = 6.32; CI = 1.37-29.07) among autoclave workers. In addition, the two deaths from brain tumour were observed among PVC compound workers.

CONCLUSIONS

To highlight the risk previously reported in the literature and to reduce the possible dilution effect (due to comparison bias, healthy worker effect), it proved methodologically pivotal to separate exposed and probably unexposed workers (considered as an internal reference group).

目的

研究在氯乙烯/聚氯乙烯生产中可能接触有毒物质和致癌物的主要工人群体中的癌症死亡率。

材料与方法

我们通过泊松回归重新分析了1658名男性的死亡率（随访时间为1972 - 1995年；35626人年；170例死亡），对年龄、入职年龄、日历期、接触时长和潜伏期进行了调整。我们计算了聚氯乙烯装袋工（n = 197）、聚氯乙烯复合材料工（n = 403）和高压釜工（n = 209）的相对风险（RR）和95%置信区间（CI）。作为内部对照，我们使用了两组工人：技术人员和雇员（主要对照：n = 202名受试者），仅为统计目的添加了其他蓝领工人群体（n = 639）（次要对照：n = 841名受试者）。

结果

将四个接触工人群体合并后，与主要对照群体相比，我们发现全因死亡率升高（RR = 2.09；CI = 1.09 - 4.00；160例死亡）、所有肿瘤死亡率升高（RR = 1.53；无显著差异；81例死亡）、肺癌死亡率升高（RR = 2.05；无显著差异；29例死亡）以及心血管疾病死亡率升高（RR = 3.57；无显著差异；29例死亡）。对每个特定群体的分析显示，聚氯乙烯装袋工（RR = 2.66；CI = 1.27 - 5.59）和聚氯乙烯复合材料工（RR = 2.68；CI = 1.36 - 5.27）的全因死亡率均升高。次要对照群体与所有接触工人群体的比较显示，其他疾病的RR升高，即肝肿瘤（RR = 4.08；无显著差异；9例死亡）、淋巴瘤和白血病（RR = 2.97；无显著差异；7例死亡）以及肝硬化（RR = 3.30；无显著差异；11例死亡）。对每个特定群体的分析显示，聚氯乙烯复合材料工中所有肿瘤的RR显著升高（RR = 1.74；CI = 1.06 - 2.85），聚氯乙烯装袋工中肺癌的RR显著升高（RR = 3.04；CI = 1.15 - 7.99），高压釜工中肝癌（RR = 9.57；CI = 1.69 - 54.1）和肝硬化（RR = 6.32；CI = 1.37 - 29.07）的RR显著升高。此外，在聚氯乙烯复合材料工中观察到2例脑肿瘤死亡。