Objectives Retrospective exposure assessment in community-based studies is largely reliant on questionnaire information. Expert assessment is often used to assess lifetime occupational exposures, but these assessments generally lack transparency and are highly time-consuming. A recent study assessing occupational exposure to diesel exhaust suggested that applying an algorithm may improve efficiency, consistency and transparency of the exposure assessment process. It is however unknown whether the observed advantages are generalisable to other occupational exposures. We explored the agreement between a rule-based assessment approach and the original case-by-case expert assessment of occupational exposure to diesel exhaust, pesticides and solvents in a community-based study.

Methods We used data from a case-control study of childhood acute lymphoblastic leukaemia in which parental occupational exposures were originally assigned by expert assessment. From the available questionnaires, we have now identified key questions and subsequently rules were written to assign exposure levels to diesel exhaust, pesticides, and solvents. We estimated exposure prevalence for control parents, separately for men and women, and used Kappa statistics to describe the agreement between the two exposure assessment methods.

Results For men, the agreement between the exposures assessed by algorithm and by expert was good to excellent for all three agents at a job level (κ = 0.60–0.83) and person level (κ = 0.65–0.86). Overall, exposure prevalence was much lower among women. Agreement was good for diesel exhaust and solvents at both job (κ = 0.67 and κ = 0.69) and person level (κ = 0.70 and κ = 0.72). Lower agreement was observed for pesticide exposure (κ = 0.40 for jobs, κ = 0.48 at person level).

Conclusions The rule-based assessment approach appeared to be an efficient way to assign occupational exposure levels in a community-based case-control study for a range of occupational exposures. It has been successfully applied in a recent study on childhood brain tumours to assess parental occupational exposures to diesel exhaust and pesticides.