title: Risk of leukaemia mortality from exposure to ionising radiation in US nuclear workers: a pooled case-control study.
abstract: OBJECTIVE
  To follow-up on earlier studies of the leukaemogenicity of occupational ionising radiation exposure.
  
  
  METHODS
  We conducted a nested case-control analysis of leukaemia mortality in a pooled cohort of US nuclear workers followed through 2005. Each case was matched to four controls on attained age. Exposures were estimated from available records. General relative risk models were used to estimate the excess relative risk (ERR) of leukaemia, excluding chronic lymphocytic (CLL), acute myeloid leukaemia, chronic myeloid leukaemia and CLL while controlling for potential confounders. Preferred exposure lags and time-windows of risks were calculated using joint maximum likelihood. Dose-response was also examined using linear, linear-quadratic, categorical and restricted cubic spline models.
  
  
  RESULTS
  There were 369 leukaemia deaths in 105 245 US nuclear workers. The adjusted ERR for non-CLL leukaemia was 0.09 (95% CI -0.17 to 0.65) per 100 mGy. Elevated non-CLL risks were observed from exposures occurring 6-14 years prior to attained age of cases (ERR per 100 mGy=1.9; 95% CI <0 to 8.0). Lagged models indicated non-linearity of risk at very low (<10 mGy) and high (>100 mGy) doses, which contributed to the imprecision of results in linear models. Similar risk attenuation was not evident in time-windows-based models.
  
  
  CONCLUSIONS
  Risk estimates were in reasonable agreement with previous estimates, with the temporality of non-CLL leukaemia risk as a dominant factor in dose-response analyses. Future research should focus on methods that improve evaluations of the dose-response, particularly in the low-dose range.
authors.affiliation: National Institute for Occupational Safety and Health (NIOSH), Division of Surveillance, Hazard Evaluations, and Field Studies (DSHEFS), Industrywide Studies Branch (IWSB), Cincinnati, OH 45226, USA. rtd2@cdc.gov
authors.forename: Robert D
authors.initials: RD
authors.lastname: Daniels
authors.forename: Stephen
authors.initials: S
authors.lastname: Bertke
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Waters
authors.forename: Mary K
authors.initials: MK
authors.lastname: Schubauer-Berigan
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D007221:Industry; D007938:Leukemia / Q000401:mortality*; D009381:Neoplasms, Radiation-Induced / Q000401:mortality*; D009688:Nuclear Reactors; D009784:Occupational Diseases / Q000401:mortality*; D016273:Occupational Exposure / Q000009:adverse effects*; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D012307:Risk Factors; D014481:United States / Q000453:epidemiology