Self‐reported history of infections and the risk of non‐Hodgkin lymphoma: An InterLymph pooled analysis

We performed a pooled analysis of data on self-reported history of infections in relation to the risk of non-Hodgkin lymphoma (NHL) from 17 case-control studies that included 12,585 cases and 15,416 controls aged 16-96 years at recruitment. Pooled odds ratios (OR) and 95% confidence intervals (95% CI) were estimated in two-stage random-effect or joint fixed-effect models, adjusting for age, sex and study centre. Data from the 2 years before diagnosis (or date of interview for controls) were excluded. A self-reported history of infectious mononucleosis was associated with an excess risk of NHL (OR = 1.26, 95% CI = 1.01-1.57 based on data from 16 studies); study-specific results indicate significant (I(2) = 51%, p = 0.01) heterogeneity. A self-reported history of measles or whooping cough was associated with an approximate 15% reduction in risk. History of other infection was not associated with NHL. We find little clear evidence of an association between NHL risk and infection although the limitations of data based on self-reported medical history (particularly of childhood illness reported by older people) are well recognized.