title: Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers.
abstract: BACKGROUND
  High benzene exposure causes acute myeloid leukaemia (AML). Three petroleum case-control studies identified 60 cases (241 matched controls) for AML and 80 cases (345 matched controls) for chronic lymphoid leukaemia (CLL).
  
  
  METHODS
  Cases were classified and scored regarding uncertainty by two haematologists using available diagnostic information. Blinded quantitative benzene exposure assessment used work histories and exposure measurements adjusted for era-specific circumstances. Statistical analyses included conditional logistic regression and penalised smoothing splines.
  
  
  RESULTS
  Benzene exposures were much lower than previous studies. Categorical analyses showed increased ORs for AML with several exposure metrics, although patterns were unclear; neither continuous exposure metrics nor spline analyses gave increased risks. ORs were highest in terminal workers, particularly for Tanker Drivers. No relationship was found between benzene exposure and risk of CLL, although the Australian study showed increased risks in refinery workers.
  
  
  CONCLUSIONS
  Overall, this study does not persuasively demonstrate a risk between benzene and AML. A previously reported strong relationship between myelodysplastic syndrome (MDS) (potentially previously reported as AML) at our study's low benzene levels suggests that MDS may be the more relevant health risk for lower exposure. Higher CLL risks in refinery workers may be due to more diverse exposures than benzene alone.
authors.affiliation: Imperial College London, Department of Epidemiology and Biostatistics, MRC-PHE Centre for Environment and Health, St Mary's Campus, Norfolk Place, London W2 1PG, UK.
authors.forename: L
authors.initials: L
authors.lastname: Rushton
authors.affiliation: ExxonMobil Biomedical Sciences, Occupational and Public Health Division, 1545 US Highway 22 East, Annandale, NJ 08801 3059, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Schnatter
authors.affiliation: University of Pittsburgh, Graduate School of Public Health, Department of Biostatistics, 130 DeSoto Street, Pittsburgh, PA 15261, USA.
authors.forename: G
authors.initials: G
authors.lastname: Tang
authors.affiliation: Monash University, Centre for Occupational and Environmental Health, Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing & Health Sciences, The Alfred Hospital, 89 Commercial Road, Melbourne Victoria 3004, Australia.
authors.forename: D C
authors.initials: DC
authors.lastname: Glass
mesh_terms: D001315:Australia; D001554:Benzene / Q000633:toxicity*; D016022:Case-Control Studies; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000139:chemically induced / Q000473:pathology*; D015470:Leukemia, Myeloid, Acute / Q000139:chemically induced / Q000473:pathology*; D016015:Logistic Models; D009190:Myelodysplastic Syndromes / Q000139:chemically induced / Q000473:pathology*; D016273:Occupational Exposure; D010578:Petroleum / Q000633:toxicity; D012307:Risk Factors
chemical_list: D010578:Petroleum; D001554:Benzene