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Updated: Jun 6, 2026

Multicellular Human Alveolar Model Composed of Epithelial Cells and Primary Immune Cells for Hazard Assessment
Published on: May 6, 2020
Household contact with pets and birds and risk of lymphoma
Saverio Bellizzi1, Pierluigi Cocco, Mariagrazia Zucca
1Department of Public Health, University of Cagliari, Policlinico Universitario, Monserrato, Italy.
Background:
Contact with household pets has been suggested to be inversely associated with lymphoma risk.
Methods:
We tested the hypothesis in a case-control study of lymphoma in the Sardinia region of Italy. Cases were 326 patients, first diagnosed with lymphoma in 1999-2003. Controls were 464 population controls, frequency matched to cases by age, gender, and area of residence. In person interviews included self-reported household contact with pets and birds, type of pet(s), and age at starting contact.
Results:
Frequent contact with birds was inversely associated with lymphoma, and particularly B-cell non-Hodgkin lymphoma (odds ratio [OR] = 0.6, 95% confidence interval [95% CI]: 0.4, 0.9). Contact with chickens accounted for this inverse association, which was strongest for first contact occurring at age ≤8 years (OR = 0.4, 95% CI: 0.2, 1.0). No association was observed when first contact occurred at age 9 or older. Contact with any pets was inversely associated with risk of diffuse large B-cell lymphoma (OR = 0.4, 95% CI: 0.2, 1.0), but not other lymphoma subtypes.
Conclusion:
Our results support the hypothesis that early-life exposure to pets, birds and particularly with chickens might be associated with a reduced risk of lymphoma.
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