Tomenson J A, Bonner S M, Edwards J C, Pemberton M A, Cummings T F, Paddle G M
ICI Epidemiology Unit, PO Box 7, Brunner House, Winnington, Northwich, Cheshire, CW8 4DJ, UK.
Occup Environ Med. 2000 Dec;57(12):810-7. doi: 10.1136/oem.57.12.810.
To study mortality among 4324 workers at two United Kingdom factories, Darwen, Lancashire and Wilton, Cleveland, producing polymethyl methacrylate (PMMA) sheet. The Darwen factory is still active, but the Wilton one was closed in 1970. Also, to investigate patterns of mortality after exposure to methyl methacrylate; in particular, mortality from colon and rectal cancer.
All male employees at the Darwen factory with a record of employment in 1949-88 and all men ever employed at the Wilton factory (1949-70) were investigated. The vital status of both cohorts was ascertained on 31 December 1995. The exposure of 1526 subjects at the Darwen plant who were engaged from 1949 onwards could be characterised. The mean duration of exposure was 7.6 years at 13.2 ppm (8 hour time weighted average), although exposures in some work groups were as high as 100 ppm. It was not possible to calculate the cumulative exposure of workers first employed at the Darwen plant before 1949 or workers at the Wilton factory.
In the Darwen cohort, 622 deaths were identified and a further 700 deaths in the Wilton cohort. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMRs). In the subcohort of Darwen workers with more than minimal exposure to MMA, reduced mortalities compared with national and local rates, were found for all causes (SMR 94), and colorectal cancer (SMR 92), but mortality from all cancers was slightly increased (SMR 104). No relations were found with cumulative exposure to MMA. In the subcohort of Wilton workers, mortality from all causes of death was significantly reduced (SMR 89), but mortality from all cancers (SMR 103) and colorectal cancer (SMR 124) were increased. The excess of colorectal cancer was confined to employees with less than 1 year of employment.
The study provided no clear evidence that employment at the factories or exposure to MMA had adversely affected the mortalities of workers.
研究英国两家生产聚甲基丙烯酸甲酯（PMMA）板材工厂（位于兰开夏郡达文和克利夫兰郡威尔顿）的4324名工人的死亡率情况。达文工厂仍在运营，但威尔顿工厂已于1970年关闭。此外，调查接触甲基丙烯酸甲酯后的死亡模式；特别是结肠癌和直肠癌的死亡率。
对达文工厂所有在1949 - 1988年有工作记录的男性员工以及所有曾在威尔顿工厂工作过（1949 - 1970年）的男性进行调查。两个队列的生命状况于1995年12月31日确定。达文工厂1526名从1949年起入职的受试者的接触情况得以描述。平均接触时长为7.6年，接触浓度为13.2 ppm（8小时时间加权平均值），不过一些工作组的接触浓度高达100 ppm。对于1949年之前首次在达文工厂工作的工人或威尔顿工厂的工人，无法计算其累积接触量。
在达文队列中，确认有622人死亡，威尔顿队列中有700人死亡。将队列的死亡率与全国和当地死亡率进行比较，并以标准化死亡比（SMR）表示。在达文工厂接触甲基丙烯酸甲酯程度超过最低限度的亚队列中，发现所有原因（SMR 94）以及结直肠癌（SMR 92）的死亡率相较于全国和当地死亡率有所降低，但所有癌症的死亡率略有上升（SMR 104）。未发现与甲基丙烯酸甲酯累积接触量存在关联。在威尔顿工厂的亚队列中，所有死因的死亡率显著降低（SMR 89），但所有癌症（SMR 103）和结直肠癌（SMR 124）的死亡率有所上升。结直肠癌的超额死亡率仅限于工作年限少于1年的员工。
该研究未提供明确证据表明在这些工厂工作或接触甲基丙烯酸甲酯对工人死亡率产生了不利影响。
