RESUMO
Lymphoma is the second most common cancer affecting Golden Retrievers and is hypothesized to arise through a complex interaction of genetic and environmental factors. The aim of this nested case-control study was to investigate the association between potential environmental pollutant sources and lymphoma risk among Golden Retrievers participating in the Golden Retriever Lifetime Study. Forty-nine Golden Retrievers with non-cutaneous lymphoma and 98 Golden Retrievers without a history of cancer matched by age, sex and neuter status were selected from the Golden Retriever Lifetime Study cohort. Geographic proximity between each dog's primary residence and nine potential sources of environmental pollution was determined. In addition, the average annual ozone and airborne fine particulate matter levels for each dog's county of residence and owner-reported secondhand smoke exposure were evaluated. Environmental pollution sources of interest included chemical plants, municipal dumps, manufacturing plants, incineration plants, railroad embankment tracks, landfills, coal plants, high-voltage transmission lines, and nuclear power plants. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each exposure of interest. Subgroup analyses were conducted to evaluate whether associations differed among 1) dogs with multicentric lymphoma, 2) dogs with B-cell lymphoma, and 3) dogs with T-cell lymphoma. No variables reached statistical significance when evaluating all cases together. However, cumulative exposure burden (household proximity to 3 or more pollution sources) approached significance within the multicentric lymphoma subgroup (OR = 2.60, 95%CI 0.99-6.86, p-value = 0.053). Patterns emerged among B- and T-cell subgroups, but none reached statistical significance. Ongoing research is warranted to discern if different environmental mechanisms may be driving B- and T-cell lymphoma immunophenotypes, consistent with previously reported regional differences in subtype prevalence.
Lymphoma is a common cancer affecting dogs, particularly Golden Retrievers. By identifying risk factors for lymphoma, work can be done to reduce harmful exposures or increase monitoring among dogs at a higher risk of disease. Using a subset of dogs from the Golden Retriever Lifetime Study, we sought to investigate whether dogs with lymphoma were more likely to live near certain environmental pollutant sources than dogs without lymphoma.Forty-nine Golden Retrievers with non-cutaneous lymphoma and 98 Golden Retrievers without a history of cancer were selected from the Golden Retriever Lifetime Study Cohort. We evaluated how close each dog lived to nine environmental pollutant sources: chemical plants, municipal dumps, manufacturing plants, incineration plants, railroad embankment tracks, landfills, coal plants, high-voltage transmission lines, and nuclear power plants. Additionally, we evaluated individual exposure to secondhand smoke, and average annual ozone and particulate matter exposure (as surrogate measures for air pollution) for each dog's county of residence.None of the exposures examined were associated with an increased lymphoma risk in this population. More research is needed, including direct biomonitoring, to determine whether specific environmental exposures are associated with lymphoma in the Golden Retriever breed.
