History of antibiotic use and risk of non-Hodgkin's lymphoma (NHL).

A population-based, incidence case-control study was conducted among women in upstate New York to determine whether histories of certain infections and antibiotic use are associated with risk of non-Hodgkin's lymphoma (NHL). Our study involved 376 cases of NHL identified through the New York State Cancer Registry and 463 controls selected from the Medicare beneficiary files and state driver's license records. Information about use of common medications including antibiotics, history of selected infectious diseases and potential confounding variables was obtained by telephone interview. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using an unconditional logistic regression model. There was a progressive increase in risk of NHL with increasing frequency and duration of systemic antibiotic use, as assessed over the period of 2-20 years before the interview. The ORs for the highest exposure categories, >/=36 episodes and >/=366 days of use, were 2.56 (95% CI 1.33-4.94) and 2.66 (95% CI 1.35-5.27), respectively. These associations were primarily due to antibiotic use against respiratory infections and dental conditions. Moreover, the association with frequency of antibiotic use for respiratory infections was pronounced for marginal zone B-cell lymphoma and for respiratory tract lymphoma. Analyses by class of antibiotics did not suggest that a general cytotoxic effect of antibiotics was responsible for these increased risks. Although recall bias and selection bias remain potential concerns in our study, the results are generally consistent with the hypothesis that persistent infection/inflammation predisposes individuals to the development of NHL. However, a direct role of antibiotics in NHL induction has not been ruled out. Copyright 2003 Wiley-Liss, Inc.