Towards Obesity Surveillance Using Multifaceted Online Social Relational Factors in Reddit
Authors: Park Albert , Ge Yaorong 
Published: May 2019

ObjectiveWe aim to better understand online social interactions and environments of individuals interested in weight management from a social media platform called Reddit.IntroductionOverweight and obesity are recognized as one of the greatest modern public health problems1, yet worldwide prevalence of obesity has nearly doubled over the past 30 years2. As part of a strategy to control the obesity pandemic, the WHO recommends an obesity surveillance at the population level3. Empirical studies have shown the importance of social networks in obesity4 and new strategies focusing on social interactions and environments have been proposed5 to prevent the further increase in obesity prevalence. With the increasing use of the internet, online social networks, interactions, and environments (i.e., online social relational factors) deserve more attention.Nearly three- quarters of Americans go online daily6, for functions like connecting with individuals via social network sites7. Like face to face interactions, studies have suggested that social interactions and networks on the internet can influence behavior changes8. Previous studies examining social networking sites typically examine a few selected social networking sites (example studies9,10), although individuals could be members of multiple social networking sites. To better leverage online social relational factors for the purpose of characterizing and monitoring population obesity trends, we investigate weight management community members’ other communities and their level of participation, a first step toward utilizing online multifactorial social interactions and environments.MethodsIn this study, we studied Reddit (http://www.reddit.com), a popular social interaction site, because Reddit hosts many subreddits (i.e., sub-communities), including weight management communities called r/loseit. First, we use a dataset11 — made available on Reddit — that had been used in many informatics studies12–14. For this study, we used a portion of the dataset from Jan 2015 to May 2015. In the first five months of 2015, 5,006,186 members were active in 96,462 subreddits, while submitting 17,851,561 posts and 266,268,920 associated comments. Second, we identified members with more than 3 posts on r/loseit in that period and removed ‘bot’ accounts by manually examining the top 20 frequent posters and their account IDs. Third, we extracted these members’ entire discussions made on Reddit, regardless of the subreddits. Fourth, we identified these members’ overall activities on Reddit and visualized in a network15.ResultsAfter removing bot accounts, we identified 7,734 members who had more than 3 posts in r/loseit from Jan 2015 to May 2015. On average, these members participated in 78.5 subreddits (standard error: 0.1; median: 49.0), while participating in 13,649 unique subreddits as a whole. Members’ participated subreddits are summarized in Figure 1. The size of the nodes represents the number of participating members and the thickness of edges represents the number of members who participated in both subreddits.ConclusionsWe present preliminary findings towards better understanding the online multifactorial social interactions and environments on a social networking site called Reddit. We provide evidence that members encounter many social interactions that occur outside of the community of our interest, the weight management community. However, what members discuss outside of the weight management community as well as the interactions’ influence on weight managements and changes remain unanswered. For example, many members also participate in a subreddit called r/fitness, a community that could share many similar interests with r/loseit. However, the purpose for participating in both communities is unknown. On the basis of our initial analysis, we suggest leveraging online multifaceted social relational factors for the purpose of characterizing and monitoring population obesity trends.References1. Jeffery, R. W. & Utter, J. The changing environment and population obesity in the United States. Obes. Res. 11 Suppl, 12S–22S (2003).2. World Health Organization. Global Health Observatory (GHO) data: Obesity. (2009). Available at: http://www.who.int/gho/ncd/risk_factors/obesity_text/en/; Archived at: http://www.webcitation.org/6rQICh7Oq.3. Bjorntorp, P. et al. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. World Health Organ. Tech. Rep. Ser. 894, i–xii, 1-253 (2000).4. Christakis, N. A. & Fowler, J. H. The spread of obesity in a large social network over 32 years. N. Engl. J. Med. 357, 370–9 (2007).5. Leroux, J. S., Moore, S. & Dubé, L. Beyond the ‘I’ in the obesity epidemic: a review of social relational and network interventions on obesity. J. 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