title: How different countries addressed the sudden growth of e-cigarettes in an online tobacco control community.
abstract: OBJECTIVE
  The sudden growth of e-cigarettes over the last decade has forced advocates and critics scrambling to bolster support for their respective sides. Bridging the divide in geographic barriers, social networking sites were an ideal meeting place for international activist communities, affording them the ability to organise events and discuss new topics in real time. This study examines how e-cigarettes are addressed in GLOBALink, an online international tobacco control community. We seek to discover if the pattern of activity in e-cigarette discussions changes over time. We are also interested in understanding the characteristics of sentiment toward e-cigarettes in discussion topics between countries with different network characteristics.
  
  
  METHODS
  Network analysis to explore the relationships between members from different countries, and sentiment analysis of messages and threads to identify patterns of how different countries address e-cigarette topics.
  
  
  METHODS
  GLOBALink, an online international tobacco control community.
  
  
  METHODS
  Network analysis based on GLOBALink members from 37 different countries. Sentiment analysis based on 853 posted messages, with over 1.4 million words.
  
  
  METHODS
  Network centrality measures in country interaction data, including degree, closeness and betweenness. Sentiment scores for each message, and differences between country scores.
  
  
  RESULTS
  The network analysis found a core/periphery structure where central countries focused on active positive discussions pertaining to e-cigarettes, while isolated and peripheral countries posted negative topics without many responses. A qualitative examination of message topics suggests that general subjects elicit more interactions than those that are context specific.
  
  
  CONCLUSIONS
  E-cigarettes are a polarising topic that can be seen in how countries appear to discuss related topics with others who share the same opinions. More work is needed to help communities stay informed of current research, and diffuse objective information. Network and sentiment analyses offer a strong combination of methodologies that can help support such efforts.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Kar-Hai
authors.initials: KH
authors.lastname: Chu
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Valente
mesh_terms: D066300:Electronic Nicotine Delivery Systems / Q000523:psychology*; D014943:Global Health; D006801:Humans; D011639:Public Opinion; D061108:Social Media; D012944:Social Support; D020340:Tobacco Use Cessation / Q000379:methods*
keywords: PUBLIC HEALTH