Cancer risks in New Zealand farmers

Previous New Zealand case-control studies have found increased risk for leukaemia, non-Hodgkin's lymphoma (NHL) and multiple myeloma in farmers. We report here a further series of New Zealand Cancer Registry based case-control studies of farming and site-specific cancer risks. These involved 19,904 males aged 20 years or more who were registered with cancer between 1980 and 1984. For each cancer site, the registrations for other sites formed the control group. Farmers had elevated risks for malignant melanoma (Odds Ratio [OR] = 1.25, 95% confidence interval [Cl] 1.05-1.50), and for cancer of the lip (OR = 2.43, 95% Cl 1.81-3.27), rectum (OR = 1.19, 95% Cl 1.03-1.38), bone (OR = 1.95, 95% Cl 1.00-3.80), prostate (OR = 1.26, 95% Cl 1.13-1.41) and brain (OR = 1.34, 95% Cl 1.04-1.74). Decreased risks were observed for cancer of the larynx (OR = 0.66, 95% Cl 0.45-0.96), lung (OR = 0.70, 95% Cl 0.63-0.77) and testis (OR = 0.58, 95% Cl 0.39-0.88). Livestock farmers had a relatively high risk for brain cancer, while the risk for cancer of the lip was highest among dairy farmers. Farmers also had increased risks for cancer of the lymphatic and haematopoietic system (International Classification of Disease 9th edn (ICD) 200-208) (OR = 1.24, 95% Cl 1.08-1.42), leukaemia (OR = 1.24, 95% Cl 0.99-1.55) and non-Hodgkin's lymphoma (NHL) (OR = 1.24, 95% Cl 0.99-1.56), as described previously.