Occupation and risk of lymphoid and myeloid leukaemia in the European Prospective Investigation into Cancer and Nutrition (EPIC).

Objectives Established risk factors for leukaemia do
not explain the majority of leukaemia cases. Previous
studies have suggested the importance of occupation
and related exposures in leukaemogenesis. We evaluated
possible associations between job title and selected
hazardous agents and leukaemia in the European
Prospective Investigation into Cancer and Nutrition.
Methods The mean follow-up time for 241 465
subjects was 11.20 years (SD 2.42 years). During the
follow-up period, 477 incident cases of myeloid and
lymphoid leukaemia occurred. Data on 52 occupations
considered a priori to be at high risk of developing
cancer were collected through standardised
questionnaires. Occupational exposures were estimated
by linking the reported occupations to a job exposure
matrix. Cox proportional hazard models were used to
explore the association between occupation and related
exposures and risk of leukaemia.
Results The risk of lymphoid leukaemia significantly
increased for working in chemical laboratories (HR 8.35,
95% CI 1.58 to 44.24), while the risk of myeloid
leukaemia increased for working in the shoe or other
leather goods industry (HR 2.54, 95% CI 1.28 to 5.06).
Exposure-specific analyses showed a non-significant
increased risk of myeloid leukaemias for exposure to
benzene (HR 1.15, 95% CI 0.75 to 1.40; HR=1.60,
95% CI 0.95 to 2.69 for the low and high exposure
categories, respectively). This association was present
both for acute and chronic myeloid leukaemia at high
exposure levels. However, numbers were too small to
reach statistical significance.
Conclusions Our findings suggest a possible role of
occupational exposures in the development of both
lymphoid and myeloid leukaemia. Exposure to benzene
seemed to be associated with both acute and chronic
myeloid leukaemia.