The process of determining occupational aetiology of a disease in an individual patient (etiologic diagnosis or Specific Causation) is central to the current practice of occupational medicine. We typically need to determine Specific Causation to assist us in decision-making related to safe return-to-work, prevention of worsening of disease or re-injury of a patient, as well as wage replacement and reimbursement of medical care expenses for patients with disabling diseases potentially of occupational aetiology. Incorrectly attributing or denying occupational causes of disease can each cause serious harm to patients, their families, their employers, coworkers, and society. Potential contributors to inaccurate determination of Specific Causation include diagnostic, toxicologic, mechanistic and exposure-related uncertainties as well as scientific limitations of medicolegal concepts, including the ‘probability of causation’ and ‘more likely than not’ criteria sometimes used in workers’ compensation decision-making. Improving accuracy of determination of Specific Causation is deserving of additional research attention.Methods
We review the current status of causal inference at the individual level in occupational medicine and apply some of the recently developed concepts in causal inference theory from epidemiology and statistics to the decision-making process in clinical occupational medicine.Results
We illustrate with examples of patients with cancer, respiratory disorders or chemical toxicity some of the limitations of the current decision-making process. We propose some modifications in approach to determination of Specific Causation that may better address issues of multiple additive or interacting causal factors, acceleration of phenotypic expression of a disease, aggravation of pre-existing disease, and challenges of applying medicolegal criteria that do not account for these factors.Discussion
We discuss alternative approaches to Specific Causation that incorporate recent scientific developments in causal inference, explicitly address some of the existing inadequacies, and aim to enable more fair and accurate decision-making with respect to occupational disease causation in individuals.