title: Bladder cancer incidence among workers exposed to o-toluidine, aniline and nitrobenzene at a rubber chemical manufacturing plant.
abstract: BACKGROUND
  An earlier investigation found increased bladder cancer incidence among workers at a rubber chemical manufacturing plant that used o-toluidine, aniline and nitrobenzene. The cohort was expanded to include additional workers (n=1875) and updated through 2007 to assess bladder cancer with improved exposure characterisation.
  
  
  METHODS
  Work histories were updated and exposure categories and ranks were developed for o-toluidine, aniline and nitrobenzene combined. Incident cancers were identified by linkage to six state cancer registries. Residency in time-dependent cancer registry catchment areas was determined. SIR and standardised rate ratios for bladder cancer were calculated by exposure category and cumulative rank quartiles for different lag periods. Cox regression was used to model bladder cancer incidence with estimated cumulative rank, adjusting for confounders. Indirect methods were used to control for smoking.
  
  
  RESULTS
  Excess bladder cancer was observed compared to the New York State population (SIR=2.87, 95% CI 2.02 to 3.96), with higher elevations among workers definitely exposed (moderate/high) (SIR=3.90, 95% CI 2.57 to 5.68), and in the highest cumulative rank quartile (SIR=6.13, 95% CI 2.80 to 11.6, 10-year lag). Bladder cancer rates increased significantly with estimated cumulative rank (10-year lag). Smoking only accounted for an estimated 8% elevation in bladder cancer incidence.
  
  
  CONCLUSIONS
  Bladder cancer incidence remains elevated in this cohort and significantly associated with estimated cumulative exposure. Results are consistent with earlier findings in this and other cohorts. Despite other concurrent chemical exposures, we consider o-toluidine most likely responsible for the bladder cancer incidence elevation and recommend a re-examination of occupational exposure limits.
authors.affiliation: Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA.
authors.forename: Tania
authors.initials: T
authors.lastname: Carreón
authors.forename: Misty J
authors.initials: MJ
authors.lastname: Hein
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Hanley
authors.forename: Susan M
authors.initials: SM
authors.lastname: Viet
authors.forename: Avima M
authors.initials: AM
authors.lastname: Ruder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000814:Aniline Compounds / Q000009:adverse effects; D002617:Chemical Industry; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D009578:Nitrobenzenes / Q000009:adverse effects*; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects*; D016016:Proportional Hazards Models; D012408:Rubber; D012907:Smoking / Q000009:adverse effects; D014052:Toluidines / Q000009:adverse effects*; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced* / Q000453:epidemiology / Q000209:etiology; D055815:Young Adult
chemical_list: D000814:Aniline Compounds; D009578:Nitrobenzenes; D014052:Toluidines; D012408:Rubber; C036077:nitrobenzene; C023650:aniline