Objective: To assess the association between occupational exposure to toluene diisocyanate or methylene diphenyldiisocyanate and risk of cancer.
Design: A cohort based case-referent study. STUDY BASE: 7023 subjects employed during the period 1958 to 1987 in nine Swedish polyurethane foam manufacturing plants.
Main outcome measures: Odds ratios adjusted with respect to the matching factors (age at risk, calendar year at risk, sex, and plant), calculated from the conditional logistic regression model.
Results: A non-significant association was found between high exposure to isocyanates and prostate cancer (OR 2.66, 90% confidence interval (90% CI) 0.39-18.1), which was not enhanced when an induction latency period of 10 years was applied. An association between isocyanate exposure and colon cancer was even weaker. No associations were seen for non-Hodgkin's lymphoma and rectal cancer.
Conclusions: The tentative associations, derived from a previous cohort study, between isocyanate exposure and excess risk for non-Hodgkin's lymphoma and rectal cancer were not supported. Instead, non-significant associations with prostate cancer, and possibly colon cancer, were seen.