title: Tracking the rise in popularity of electronic nicotine delivery systems (electronic cigarettes) using search query surveillance.
abstract: BACKGROUND
  Public interest in electronic nicotine delivery systems (ENDS) is undocumented.
  
  
  OBJECTIVE
  By monitoring search queries, ENDS popularity and correlates of their popularity were assessed in Australia, Canada, the United Kingdom (UK), and the U.S.
  
  
  METHODS
  English-language Google searches conducted from January 2008 through September 2010 were compared to snus, nicotine replacement therapy (NRT), and Chantix® or Champix®. Searches for each week were scaled to the highest weekly search proportion (100), with lower values indicating the relative search proportion compared to the highest-proportion week (e.g., 50=50% of the highest observed proportion). Analyses were performed in 2010.
  
  
  RESULTS
  From July 2008 through February 2010, ENDS searches increased in all nations studied except Australia, there an increase occurred more recently. By September 2010, ENDS searches were several-hundred-fold greater than searches for smoking alternatives in the UK and U.S., and were rivaling alternatives in Australia and Canada. Across nations, ENDS searches were highest in the U.S., followed by similar search intensity in Canada and the UK, with Australia having the fewest ENDS searches. Stronger tobacco control, created by clean indoor air laws, cigarette taxes, and anti-smoking populations, were associated with consistently higher levels of ENDS searches.
  
  
  CONCLUSIONS
  The online popularity of ENDS has surpassed that of snus and NRTs, which have been on the market for far longer, and is quickly outpacing Chantix or Champix. In part, the association between ENDS's popularity and stronger tobacco control suggests ENDS are used to bypass, or quit in response to, smoking restrictions. Search query surveillance is a valuable, real-time, free, and public method to evaluate the diffusion of new health products. This method may be generalized to other behavioral, biological, informational, or psychological outcomes manifested on search engines.
authors.affiliation: Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA. jayers@jhsph.edu
authors.forename: John W
authors.initials: JW
authors.lastname: Ayers
authors.forename: Kurt M
authors.initials: KM
authors.lastname: Ribisl
authors.forename: John S
authors.initials: JS
authors.lastname: Brownstein
mesh_terms: D016503:Drug Delivery Systems / Q000639:trends*; D004867:Equipment Design; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data; D009538:Nicotine / Q000008:administration & dosage*; D012907:Smoking; D016540:Smoking Cessation / Q000379:methods
chemical_list: D009538:Nicotine