Wong O
ENSR Health Sciences, Alameda, CA 94501.
Br J Ind Med. 1990 Nov;47(11):753-62. doi: 10.1136/oem.47.11.753.
The cohort consisted of 15,908 men and women who worked for at least six months between 1948 and 1977 in 30 participating manufacturing plants in the reinforced plastics and composites industry. These workers were occupationally exposed to the working environment in the industry, which included exposure to styrene. Cause specific mortality analyses were performed based on the standardised mortality ratio (SMR) with the United States population as a comparison. No significant excess of cause specific mortality was found for the total cohort. Mortality from cancer was slightly less than expected (SMR = 88.1). For cancer of the respiratory system, a small non-significant excess was detected (SMR = 116.1). For lymphatic and haematopoietic cancer, a non-significant deficit was found (SMR = 73.3). The observed mortality from leukaemia was similar to that expected (five observed v 4.76 expected deaths). The plants with hot processes (injection moulding, centrifugal casting, compression moulding, continuous lamination, and pultrusion) experienced a significantly increased SMR (177.9) for respiratory cancer, which was more than twice that (78.3) for those with cold processes (resin mixing, lay up and spray up, bag moulding, and filament winding). As potential exposure to styrene from hot processes is considerably less than that from the cold processes, this finding could not be attributed to occupational exposures. A subsequent nested case-control study consisting of 40 cases of deaths from respiratory cancer was conducted. Further information on detailed work history, occupational exposures, and smoking history was collected. The case-control study did not show any significant association between respiratory cancer and direct exposure to styrene (contained in polyester resins), duration of exposure to styrene, the type of process (hot or cold), or whether a resin was used. A statistically significant association (relative risk = 7.33) was found between cigarette smoking and respiratory cancer among the study subjects.
该队列由15908名男性和女性组成，他们在1948年至1977年期间，于30家参与研究的增强塑料和复合材料行业制造工厂工作至少六个月。这些工人在职业上接触该行业的工作环境，其中包括接触苯乙烯。以美国人口作为对照，基于标准化死亡比（SMR）进行了特定病因死亡率分析。整个队列未发现特定病因死亡率有显著超额。癌症死亡率略低于预期（SMR = 88.1）。呼吸系统癌症方面，检测到有少量不显著的超额（SMR = 116.1）。淋巴和造血系统癌症方面，发现有不显著的不足（SMR = 73.3）。观察到的白血病死亡率与预期相似（观察到5例死亡，预期4.76例死亡）。采用热加工工艺（注塑、离心铸造、模压、连续层压和拉挤成型）的工厂，呼吸系统癌症的SMR显著升高（177.9），是采用冷加工工艺（树脂混合、铺层和喷涂、袋压成型和纤维缠绕）工厂（78.3）的两倍多。由于热加工工艺中苯乙烯的潜在接触量远低于冷加工工艺，这一发现不能归因于职业接触。随后进行了一项巢式病例对照研究，包括40例呼吸系统癌症死亡病例。收集了关于详细工作史、职业接触和吸烟史的进一步信息。病例对照研究未显示呼吸系统癌症与直接接触苯乙烯（聚酯树脂中所含）、苯乙烯接触时长、工艺类型（热或冷）或是否使用树脂之间存在任何显著关联。在研究对象中，发现吸烟与呼吸系统癌症之间存在统计学显著关联（相对风险 = 7.33）。
