title: Panel 1: Epidemiology, natural history, and risk factors.
abstract: BACKGROUND
  The First International Symposium on Recent Advances in Otitis Media (OM) with Effusion was held in Columbus, Ohio, in 1975. The symposium has been organized in the United States every 4 years since, followed by a research conference to (a) assess major research accomplishments, (b) identify important research questions and opportunities, (c) develop consensus on definitions and terminology, and (d) establish priorities with short- and long-term research goals. One of the principal areas reviewed quadrennially is Epidemiology, Natural History, and Risk Factors.
  
  
  OBJECTIVE
  To provide a review of recent literature on the epidemiology, natural history, and risk factors for OM.
  
  
  METHODS
  A search of OM articles in English published July 2007 to June 2011 was conducted using PubMed and related databases. Those with findings judged of importance for epidemiology, public health, and/or statistical methods were reviewed.
  
  
  RESULTS
  The literature has continued to expand, increasing understanding of the worldwide burden of OM in childhood, complications from treatment failures, and comorbidities. Novel risk factors, including genetic factors, have been examined for OM susceptibility. Population-based studies in Canada, the United States, and other countries confirmed reductions in OM prevalence. Although most studies concentrated on acute OM (AOM) or OM with effusion (OME), a few examined severe chronic suppurative OM (CSOM), a major public health problem in developing countries and for certain indigenous populations around the world.
  
  
  CONCLUSIONS
  Recent publications have reinforced earlier epidemiological findings, while extending our knowledge in human population groups with high burden of OM.
authors.affiliation: Epidemiology and Statistics Program, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, Maryland 20892, USA. hoffmanh@nidcd.nih.gov
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Hoffman
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Daly
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Bainbridge
authors.forename: Margaretha L
authors.initials: ML
authors.lastname: Casselbrant
authors.forename: Preben
authors.initials: P
authors.lastname: Homøe
authors.forename: Ellen
authors.initials: E
authors.lastname: Kvestad
authors.forename: Kari Jorunn
authors.initials: KJ
authors.lastname: Kvaerner
authors.forename: Louis
authors.initials: L
authors.lastname: Vernacchio
mesh_terms: D002170:Canada / Q000453:epidemiology; D003226:Congresses as Topic; D003906:Developing Countries; D019317:Evidence-Based Medicine; D006801:Humans; D010033:Otitis Media / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D010034:Otitis Media with Effusion / Q000453:epidemiology / Q000209:etiology; D010035:Otitis Media, Suppurative / Q000453:epidemiology / Q000209:etiology; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology