Non-Hodgkin's lymphoma and occupational exposure to chemicals in Canada. Canadian Cancer Registries Epidemiology Research Group.

BACKGROUND

The incidence of non-Hodgkin's lymphoma (NHL) has been increasing in Canada. This study assessed the effect of occupational exposure to specific chemicals on the risk of NHL.

PATIENTS AND METHODS

Mailed questionnaires were used to obtain data on 1469 newly diagnosed, histologically confirmed NHL cases and 5073 population controls between 1994 and 1997 in eight Canadian provinces. Data was collected on socioeconomic status, life-style, diet, occupation, and years of exposure to any of 17 chemicals. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived by logistic regression.

RESULTS

The study found an increased risk of NHL among males exposed to benzidine, mineral, cutting, or lubricating oil, pesticides, and herbicides. Compared with non-exposure to each specific chemical, the adjusted ORs were 1.9 (95% CI: 1.1-3.4) for benzidine, 1.3 (95% CI: 1.0-1.5) for mineral, cutting, or lubricating oil, 1.3 (95% CI: 1.0-1.6) for herbicides, and 1.3 (95% CI: 1.0-1.6) for pesticides. Excess risk of NHL among females was associated with exposure to pesticides and wood dust. ORs increased with increasing exposure in years to benzidine and herbicides for males and with increasing exposure years to wood dust for females. These trends were statistically significant (P < 0.05).

CONCLUSIONS

The findings in this study suggest that occupational exposure to specific chemicals plays an important role in the development of NHL in Canada.