Exposure to animals and increased risk of marginal zone B-cell lymphomas of the ocular adnexae

BACKGROUND: Ocular adnexal marginal zone B-cell lymphoma (OAMZL) has been associated with Chlamydophila psittaci, an infection that may be transmitted by carrier animals. However, it is still unclear whether exposure to animals affects the risk of OAMZL in comparison with other lymphoma histotypes. We therefore investigated the role of professional and/or domestic exposures to animals in the occurrence of OAMZL, as compared with other types of lymphoma. METHODS: A hospital-based case–control study was carried out on 43 consecutive OAMZL patients (cases) and 87 consecutive patients with nodal non-Hodgkin's lymphomas (NHLs; controls). Multiple logistic regression (MLR) odds ratios (ORs), and 95% confidence intervals (CIs) were used to estimate the association between exposures to animals and OAMZL risk. RESULTS: A higher proportion of cases reported a lifetime exposure to household animals (79.1% vs 64.4% among controls), with a non-statistical significant MLR-OR of 2.18 (95% CI: 0.85–5.62). The OAMZL cases more frequently reported a history of occupation in breeding and/or slaughtering than controls (34.9% vs 6.9%), with an overall increased risk of 7.69 (95%CI: 2.65–22.34). CONCLUSION: These results indicate that, compared with nodal NHLs, the risk of OAMZL is markedly increased by contact with animals, particularly by occupational exposures.