Respiratory tract infections and subsequent risk of chronic lymphocytic leukemia

Ola Landgren, Joshua S. Rapkin, Neil E. Caporaso, Lene Mellemkjaer, Gloria Gridley, Lynn R. Goldin, Eric A. Engels

Research output: Contribution to journalArticlepeer-review

86 Scopus citations


Recent evidence suggests that chronic lymphocytic leukemia (CLL) might occur following a response to an infectious agent. We conducted a population-based study including 4249 CLL patients diagnosed in Denmark from 1977 to 1997 and 15 690 frequency-matched controls to quantify risk of CLL following various airway infections. Through data linkage we gathered information on hospital inpatient/outpatient discharges that listed infections present at least 1 year prior to CLL. Using logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (CIs). Personal history of pneumonia was associated with significantly increased CLL risk (OR = 1.4; 1.2-1.8); risk was restricted to 1 to 4.99 years prior to CLL diagnosis (OR = 1.6; 1.2-2.0). Individuals with 3 or more prior pneumonia events had a significant 2.5-fold (1.1-5.6) elevated CLL risk, and risk increased with the number of pneumonia episodes (Ptrend < .001). None of 9 other respiratory-tract infections was significantly associated with CLL risk. Pneumonia might be a potential CLL trigger or it could represent premalignant immune disruption preceding CLL.

Original languageEnglish (US)
Pages (from-to)2198-2201
Number of pages4
Issue number5
StatePublished - Mar 1 2007
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology


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