Linking Network Characteristics of Online Social Networks to Individual Health: A Systematic Review of Literature

Social networks have long been viewed as a structural determinant of health. With the proliferation of digital technologies, numerous studies have examined the health implications of online social networks (OSNs). However, the mechanisms through which OSNs may influence individual health are poorly understood. Employing a social network approach, this paper presents a systematic review of the literature examining how network characteristics of OSNs are linked to individuals' health behavior and/or status. Drawing on keyword searches in nine databases, we identified and analyzed 22 relevant articles from 1,705 articles published prior to 2017. The findings show that individual health is associated with a number of network characteristics, including both individual-level attributes (e.g., centrality) and network-level attributes (e.g., density, clustering). All of the included studies (n= 22) have focused on egocentric networks, and nine studies also collected whole network data of online health communities. Based on our review, we highlight three fruitful areas in the application of OSNs in public health: (1) disease and risk detection, (2) disease prevention and intervention, and (3) health behavior change. However, the precise mechanisms and causal pathways through which OSNs affect health remain unclear. More theoretically grounded, longitudinal, and mixed methods research is needed to advance this line of research.