A case-control study of cancer mortality at a transformer-assembly facility

Abstract

To address earlier reports of excess cancer mortality associated with employment at a large transformer manufacturing plant, each plant operation was rated for seven exposures: Pyranol (a mixture of polychlorinated biphenyls and trichlorobenzene), trichloroethylene, benzene, mixed solvents, asbestos, synthetic resins, and machining fluids. Site-specific cancer deaths among active or retired employees were cases; controls were selected from deaths (primarily cardiovascular deaths) presumed to be unassociated with any of the study exposures. Using job records, we then computed person-years of exposure for each subject. All subjects were white males. The only unequivocal association was that of resin systems with lung cancer (odds ratio = 2.2 at 16.6 years of exposure, P = 0.001, in a multiple logistic regression including asbestos, age, year of death, and year of hire). Certain other odds ratios appeared larger, but no other association was so robust and remained as distinct after considering the multiplicity of comparisons. Study power was very limited for most associations, and several biases may have affected our results. Nevertheless, further investigation of synthetic resin systems of the type used in the study plant appears warranted.

Trichloroethylene and cancer: epidemiologic evidence.

“…The findings from the case-control studies (54)(55)(56)(78)(79)(80)83,84) shown in Table 12 add further support for an association between solvents, specifically TCE, and nonHodgkin's lymphoma. Six of seven studies showed elevated ORs, two were statistically significant, and several reported TCE (rather than general solvent) exposure.…”

“…In addition to several reviews human evidence evidence (13). (115) and Swaen (116) about the design of their study (10), calculate the combined OR among six case-control studies (60)(61)(62)(63)(64)83) McLaughlin and Blot (116) subsequently review the epidemiology of TCE and kidney cancer in seven cohort studies (10,18,19,24,30,31,104) and six case-control studies (57,(60)(61)(62)83,84) In their discussion, they fail to distinguish results either between men and women or incidence and mortality, and argue that none of the cohort studies except "the methodologically questionable" Henschler et al. study (10) The newest data on kidney cancer suggest different interpretations, although Weiss (6) and McLaughlin and Blot (117) caution the reader on the interpretation of these results because the Tier I cohort studies they had available showed, at best, a weak response.…”

“…Since the average 5-year survival for people with pancreatic cancer is below 5% (103), incidence and mortality are of comparable validity as measures of effect. There is evidence for a protective effect from the case-control studies with solvent exposure (82,83), evidence for cancer risk with TCE exposure (83), and evidence for cancer risk with dry cleaning and laundry work including an exposure-response relationship (81). Since the effect is strongest in Tier III studies and also seen in dry cleaner and laundry worker studies, this outcome is likely to be linked to dry cleaner exposures.…”

A meta-analysis of occupational trichloroethylene exposure and multiple myeloma or leukaemia

“…Three US studies included aerospace or aircraft worker cohorts [22][23][24], while four European studies included cohorts of workers from various occupational groups who were exposed to TCE [26][27][28][29]. In a case-control study of US transformer manufacturing plant workers, Greenland et al [25] presented results for leukaemia, based on TCE job exposure matrices Historical measurement files were used to select TCE-using industries. The primary industries representing the cohort of workers were iron and metal, followed by electronics and painting Hansen et al,…”

Mortality studies of machining fluid exposure in the automobile industry IV; a case-control study of lung cancer

“…Elevated risk ratios (RR) were found for nonwelding metal workers (RR 1.70) and for stainless steel grinders (7 observations, RR 2.85) in a retrospective cohort study of Danish metal workers [Stagis Hansen, 1990]. In contrast, exposure to machining fluids did not appear to increase the risk of lung cancer in a cohort of more than 5,000 metal machinists [Decouflé, 1978], or in workers at a transformerassembly facility [Greenland et al, 1994]. Swedish metal workers exposed to oil mists [Jarvholm and Lavenius, 1987], bearing plant workers exposed to a variety of cutting fluids , and Finnish machine shop workers [Tola et al, 1988] were also found to have levels of lung cancer risk comparable to those of referent groups.…”