Occupation and Risk of Non-Hodgkin Lymphoma and Its Subtypes: A Pooled Analysis from the InterLymph Consortium

BACKGROUND: Various occupations have been associated with an elevated NHL risk but results have been inconsistent across studies. OBJECTIVES: To investigate occupational risk of non-Hodgkin lymphoma (NHL) and four common NHL subtypes with particular focus on occupations of a priori interest. METHODS: We conducted a pooled analysis of 10,046 cases and 12,025 controls from 10 NHL studies participating in the InterLymph Consortium. We harmonized the occupational coding using the 1968 International Standard Classification of Occupations (ISCO) and grouped occupations previously associated with NHL into 25 a priori groups. Odds ratios (OR), adjusted for center, age and sex were determined for NHL overall and the subtypes diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and peripheral T-cell lymphoma (PTCL). RESULTS: We confirmed previously reported positive associations between NHL and farming occupations (field crop/vegetable farm workers OR = 1.26; 95% confidence interval (CI): 1.05, 1.51; general farm workers OR = 1.19, 95% CI: 1.03, 1.37), and with specific occupations as women's hairdressers (OR = 1.34; 95% CI: 1.02, 1.74), charworkers/cleaners (OR = 1.17; 95% CI: 1.01, 1.36), spray-painters (OR = 2.07; 95% CI: 1.30, 3.29), electrical wiremen (OR = 1.24; 95% CI: 1.00, 1.54), and carpenters (OR = 1.42; 95% CI: 1.04, 1.93). We observed subtype specific associations for DLBCL and CLL/SLL in women's hairdressers and for DLBCL and PTCL in textile workers. CONCLUSIONS: Our pooled analysis of 10 international studies adds to evidence suggesting that farming, hairdressing, and textile industry-related exposures may contribute to NHL risk. Associations with women's hairdresser and textile occupations may be specific for certain NHL subtypes