Abstract

Online user comments (UCs), increasingly prevalent across a wide array of internet platforms, offer users the opportunity to share their experiences and opinions. In the context of health communication, UCs serve as supplementary information sources, providing personal insights and peer perspectives. Although there is relevant research exploring the role of online user comments in health communication, these studies have not focused specifically on their impact on human behavior. This study aims to systematically examine how UCs influence health-related behaviors. A sample of 29 articles was identified through systematic literature searches and screening processes. First, this review offers an overview of the field. Studies were conducted across various national contexts, with the majority originating from the United States (n=22). Many of these studies utilized simulated online platforms, such as Facebook (n=13) and news websites (n=9), to replicate realistic environments for analyzing user comments. The studies covered a broad spectrum of health topics, with nine specifically focusing on vaccines. Second, the review highlights the effects of UCs on health behaviors, health information-related behaviors, and health-related consumption behaviors. Comment valence emerged as one of the most frequently discussed attributes influencing health-related behaviors. Rather than focusing on a single feature, most studies examined the effects of interactions between multiple attributes of user comments. Typically, UCs exert an indirect influence on health-related behaviors by affecting cognition or emotion. In conclusion, this review contributes to a deeper understanding of the mechanisms through which UCs impact health-related behaviors and offers practical insights for enhancing health communication strategies.