title: Using Search Engine Query Data to Explore the Epidemiology of Common Gastrointestinal Symptoms.
abstract: Internet searches are an increasingly used tool in medical research. To date, no studies have examined Google search data in relation to common gastrointestinal symptoms.
  
  
  
  The aim of this study was to compare trends in Internet search volume with clinical datasets for common gastrointestinal symptoms.
  
  
  
  Using Google Trends, we recorded relative changes in volume of searches related to dysphagia, vomiting, and diarrhea in the USA between January 2008 and January 2011. We queried the National Inpatient Sample (NIS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS) during this time period and identified cases related to these symptoms. We assessed the correlation between Google Trends and these two clinical datasets, as well as examined seasonal variation trends.
  
  
  
  Changes to Google search volume for all three symptoms correlated significantly with changes to NIS output (dysphagia: r = 0.5, P = 0.002; diarrhea: r = 0.79, P < 0.001; vomiting: r = 0.76, P < 0.001). Both Google and NIS data showed that the prevalence of all three symptoms rose during the time period studied. On the other hand, the NHAMCS data trends during this time period did not correlate well with either the NIS or the Google data for any of the three symptoms studied. Both the NIS and Google data showed modest seasonal variation.
  
  
  
  Changes to the population burden of chronic GI symptoms may be tracked by monitoring changes to Google search engine query volume over time. These data demonstrate that the prevalence of common GI symptoms is rising over time.
authors.affiliation: Division of Gastroenterology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA. bhassid@gmail.com.
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Hassid
authors.affiliation: Division of Gastroenterology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.
authors.forename: Lukejohn W
authors.initials: LW
authors.lastname: Day
authors.affiliation: Department of Urology, University California of San Francisco, San Francisco, CA, USA.
authors.forename: Mohannad A
authors.initials: MA
authors.lastname: Awad
authors.affiliation: Division of Gastroenterology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.
authors.forename: Justin L
authors.initials: JL
authors.lastname: Sewell
authors.affiliation: Division of Gastroenterology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.
authors.forename: E Charles
authors.initials: EC
authors.lastname: Osterberg
authors.affiliation: Division of Gastroenterology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA.
authors.forename: Benjamin N
authors.initials: BN
authors.lastname: Breyer
mesh_terms: D017281:Cost of Illness; D003680:Deglutition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology*; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D019538:Health Care Surveys / Q000706:statistics & numerical data*; D006801:Humans; D057226:Information Seeking Behavior; D020407:Internet / Q000639:trends; D015995:Prevalence; D057386:Search Engine / Q000706:statistics & numerical data*; D013223:Statistics as Topic / Q000639:trends; D063189:Symptom Assessment / Q000523:psychology / Q000706:statistics & numerical data / Q000639:trends; D014481:United States / Q000453:epidemiology; D014839:Vomiting / Q000175:diagnosis / Q000453:epidemiology*
keywords: Diarrhea; Dysphagia; Epidemiology; Google; Trends; Vomiting