Ever-use of the organophosphates chlorpyrifos (hazard ratio [HR], 1.4; 95% CI, 1.0-2.0) and terbufos (HR, 1.5; 95% CI, 1.0-2.1) was significantly associated with breast cancer among farmers’ wives during a mean follow-up of 14.7 years in a prospective cohort study.18
An increased risk of gastric cancer was significantly associated with use of 2,4-D (OR, 1.85; 95% CI, 1.05-3.25), chlordane (OR, 2.96; 95% CI, 1.48-5.94), and propargite (OR, 2.86; 95% CI, 1.56-5.23) in a case-control study.23
A nested case-control study demonstrated an increased risk of rectal cancer with increasing exposure to chlorpyrifos, with the highest exposure level resulting in an OR of 2.7 (95% CI, 1.2-6.4; P-trend = .008).24 A similar finding was observed with aldicarb and colon cancer, with the highest exposure level resulting in an OR of 4.1 (95% CI, 1.3-12.8; P-trend = .001).
A nested case-control study of Hispanic farm workers in California demonstrated a significant association between vegetable cultivation and any lymphohematopoietic cancer (OR, 1.67; 95% CI, 1.12-2.48).25 An increased risk of NHL was associated with 2,4-D use (OR, 3.80; 95% CI, 1.85-7.81) and leukemia was associated with mancozeb (OR, 2.35; 95% CI, 1.12-4.95) and toxaphene (OR, 2.20; 95% CI, 1.04-4.65) exposure.
A larger study conducted in 6 European countries that included 2348 lymphoma cases and 2462 controls found that chronic lymphocytic leukemia was significantly associated with ever-exposure to inorganic (OR, 1.6; 95% CI, 1.0-2.5) and organic (OR, 1.5; 95% CI, 1.0-2.1) pesticides, particularly organophosphates (OR, 2.7; 95% CI, 1.206.0).26 Lymphoma and B cell lymphoma were not associated with pesticide use.
A case-control study conducted in the United States demonstrated that NHL was significantly associated with high exposures to DDT (RR, 1.7; 95% CI, 1.1-2.6) and lindane (RR, 2.5; 95% CI, 1.4-4.4), and follicular lymphoma was associated with high exposure to diazinon (RR, 3.8; 95% CI, 1.2-11.4) compared with no exposure.27
The same US-based study showed that there was an increased risk of multiple myeloma (MM) among workers exposed to high levels of permethrin (RR, 3.1; 95% CI, 1.5-6.2) compared with no exposure.27 A pooled analysis of 3 case-control studies conducted in North America also demonstrated an increased risk among male, but not female, farmers for MM with ever use of several other pesticides, including carbaryl (OR, 2.02; 95% CI, 1.28-3.21), captan (OR, 1.98; 95% CI, 1.04-3.77), and DDT (OR, 1.44; 95% CI, 1.05-1.97), though most responses were by proxy.28