A meta-analysis of occupational trichloroethylene exposure and multiple myeloma or leukaemia.
BACKGROUND
Trichloroethylene (TCE) has been widely used as an industrial solvent and degreasing agent.


OBJECTIVE
We conducted a meta-analysis of epidemiologic studies of occupational TCE exposure and multiple myeloma (MM) or leukaemia.


METHODS
We identified a total of eight cohort or case-control studies that enumerated a TCE-exposed study population and presented relative risk (RR) estimates for MM (n = 7) and/or leukaemia (n = 7). The individual studies included aerospace or aircraft workers (n = 3 studies), workers from a transformer manufacturing plant (n = 1 study) and workers from numerous occupations who, based on biomonitoring or extensive industrial hygiene exposure measurements, were likely exposed to TCE (n = 4). We used random effects models to calculate summary relative risk estimates (SRRE). In addition, we examined heterogeneity across studies and the relative influence of each individual study on the overall meta-analysis.


RESULTS
No association was observed for MM (SRRE = 1.05, 95% CI: 0.80-1.38; P value for heterogeneity = 0.94) or leukaemia (SRRE = 1.11, 95% CI: 0.93-1.32; P value for heterogeneity = 0.50), based on TCE-exposed subgroup meta-analyses. Study-specific RR estimates for MM ranged between 0.57 and 1.62. RRs for leukaemia ranged between 1.05 and 1.15 in five studies, while one study reported a 2-fold increased RR and another study reported an inverse association of 0.60. All confidence intervals (CIs) for study-specific estimates included 1.0.


CONCLUSIONS
The results of this meta-analysis do not support an etiologic association between occupational TCE exposure and risk of MM or leukaemia.
Alexander
Dominik D
DD
Exponent-Health Sciences, 185 Hansen Court, Suite 100, Wood Dale, IL 60191, USA. dalexander@exponent.com
Mink
Pamela J
PJ
Mandel
Jeffrey H
JH
Kelsh
Michael A
MA
D000337:Aerospace Medicine; D006801:Humans; D007221:Industry; D007938:Leukemia / Q000139:chemically induced* / Q000453:epidemiology; D009101:Multiple Myeloma / Q000139:chemically induced* / Q000453:epidemiology; D009784:Occupational Diseases / Q000139:chemically induced*; D016273:Occupational Exposure / Q000009:adverse effects; D018570:Risk Assessment / Q000379:methods; D012997:Solvents / Q000633:toxicity*; D014241:Trichloroethylene / Q000633:toxicity*
D012997:Solvents; D014241:Trichloroethylene