Medical history, lifestyle, family history, and occupational risk factors for marginal zone lymphoma: The interLymph non-Hodgkin lymphoma subtypes project

Background: Marginal zone lymphoma (MZL), comprised of nodal, extranodal, and splenic subtypes, accounts for 5%-10% of non-Hodgkin lymphoma cases. A detailed evaluation of the independent effects of risk factors for MZL and its subtypes has not been conducted. Methods: Data were pooled from 1052 MZL cases (extranodal [EMZL] = 633, nodal [NMZL] = 157, splenic [SMZL] = 140) and 13 766 controls from 12 case-control studies. Adjusted unconditional logistic regression was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). Results: Novel findings for MZL subtypes include increased risk for B-cell activating autoimmune conditions (EMZL OR = 6.40, 95% CI = 4.24 to 9.68; NMZL OR = 7.80, 95% CI = 3.32 to 18.33; SMZL OR = 4.25, 95% CI = 1.49 to 12.14), hepatitis C virus seropositivity (EMZL OR = 5.29, 95% CI = 2.48 to 11.28), self-reported peptic ulcers (EMZL OR = 1.83, 95% CI = 1.35 to 2.49), asthma without other atopy (SMZL OR = 2.28, 95% CI = 1.23 to 4.23), family history of hematologic cancer (EMZL OR = 1.90, 95% CI = 1.37 to 2.62) and of non-Hodgkin lymphoma (NMZL OR = 2.82, 95% CI = 1.33 to 5.98), permanent hairdye use (SMZL OR = 6.59, 95% CI = 1.54 to 28.17), and occupation as a metalworker (NMZL OR = 3.56, 95% CI = 1.67 to 7.58). Reduced risks were observed with consumption of any alcohol (EMZL fourth quartile OR = 0.48, 95% CI = 0.28 to 0.82) and lower consumption of wine (NMZL first to third quartile ORs < 0.45) compared with nondrinkers, and occupation as a teacher (EMZL OR = 0.58, 95% CI = 0.37 to 0.88). Conclusion: Our results provide new data suggesting etiologic heterogeneity across MZL subtypes although a common risk of MZL associated with B-cell activating autoimmune conditions was found.