Association between canine malignant lymphoma, living in industrial areas,and use of chemicals by dog owners

A case-control study was carried out to determine whether residential expos ure to environmental pollutants increased risk for canine lymphoma in pet d ugs. One hundred one cases with cyctologically or histologically confirmed lymphoma diagnosed at a veterinary teaching hospital between the middle of 1996 and the middle of 1998 were examined. Controls were obtained by choosi ng twice the number of dogs without neoplastic disease. with overlapping di stributions of province of residence, age, sex. and breed. Information rega rding animal management. residence type, professional or hobby use of chemi cals by owners, and treatment with herbicides or other pesticides in the ar ea li frequently visited by the dogs was obtained with a multiple-choice qu estionnaire by telephone interview. Two variables were positively and indep endently associated with the disease. namely residency in industrial areas (odds ratio [OR]: = 8.5: 95% confidence interval [CI]. 2.3-30.9) and use of chemicals by owners, specifically paints or solvents (OR = 4.6: 95% CI. 1. 7-12.6). A significantly lower value of the mean apr of disease onset was f ound in the group of dogs at risk in comparison with the group of all other dogs (6.1 +/- 0.4 years, n = 36 versus 7.5 +/- 0.4 years. n = 65, respecti vely; P = .008). Variables describing animal care and pesticide use were ei ther not associated with the disease or were uninformative. We suggest that canine lymphoma may be considered a sentinel of potentially hazardous situ ations for humans, because of the relatively short latency between exposure and disease onset.