摘要：As Web 2.0 and social media make the communication landscape increasingly participatory, empirical evidence is needed regarding their impact on and utility for health promotion. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched 4 medical and social science databases for literature (2004–present) on the intersection of Web 2.0 and health. A total of 514 unique publications matched our criteria. We classified references as commentaries and reviews (n = 267), descriptive studies (n = 213), and pilot intervention studies (n = 34). The scarcity of empirical evidence points to the need for more interventions with participatory and user-generated features. Innovative study designs and measurement methods are needed to understand the communication landscape and to critically assess intervention effectiveness. To address health disparities, interventions must consider accessibility for vulnerable populations. WEB 2.0 TECHNOLOGIES HAVE significantly changed the health communication landscape in recent years. Leaving the health impact aside, we have witnessed a shift in the online environment, from unidirectional and “read-only” (whereby information is “pushed” on passive audiences) to multidirectional communication characterized by participation, collaboration, and openness. 1,2 Through social media sites such as Facebook, YouTube, blogs, and forums, individuals obtain information and contribute to online content in an interactive, networked environment. For instance, the online community PatientsLikeMe helps individuals connect with others with the same illness and share information about symptoms and treatment options. 3 If one considers public health, Web 2.0 media are challenging traditional health promotion models and prompting the advancement of innovative health promotion and communication methods with rigorous impact assessment. 2,4–6 In response to the growing participatory communication environment, public health practitioners and researchers have begun undertaking descriptive and intervention studies to assess how Web 2.0 and social media shape health-related knowledge, attitudes, and behavior. In addition, a number of Web 2.0–based interventions have recently been tested to evaluate feasibility, usability, and effectiveness for different populations. Health outcome impact assessments for a diverse range of health topics are only beginning to take shape given the rapid developments in Web 2.0 technologies. A key research question facing the changing communication landscape centers on the issue of the digital divide. Inequalities in access to and use of technologies have been observed, whereby those of lower socioeconomic status, minority race/ethnicity, older age, poorer health, and living in geographically isolated locations are less likely to have adequate access. 7–13 A 2009 Federal Communication Commission survey indicated that the main dividing lines for broadband access are along socioeconomic dimensions such as income and education. 14 Furthermore, research on health information technology adoption has found disparities in access and utilization patterns across socioeconomic groups and health literacy levels. 15 Indeed, the digital divide parallels patterns of health disparities in many ways. On the other hand, there is growing evidence that the digital divide may be narrowing. Nationally representative data indicate that, when Internet access is controlled for, race/ethnicity, income, and education do not dictate social media participation. 16 With equal likelihood of accessing social media, populations suffering disproportionately from health disparities are afforded unprecedented opportunities for online information and services. Moreover, mobile technologies are increasingly accessible regardless of demographics. In 2010, 40% of American adults used a mobile phone to access the Internet and text messages, up from 32% in 2009 17 ; of interest, ethnic minorities were more likely than Whites to own a cell phone and to utilize a wider variety of its data-based functions. In a similar way, mobile phone use has begun to diminish the impact of income on Internet access; a recent survey found that 27% of adolescents with mobile phones used them to access the Internet, and, for adolescents from lower-income households, the rate jumped to 41%. 18 This is evidence that mobile phones are lowering the access barrier to Web 2.0 technologies. Empirical evidence is gradually emerging to inform participatory and “bottom-up” health interventions for various population segments. Although the characteristics of social media are identified in some recent publications, a number of key questions remain to be answered through a critical literature review: How is the current Web 2.0 environment affecting health attitudes and beliefs? What are the outcomes of social media–based health interventions? How have they been assessed? What proportion of interventions target populations that face health disparities and what are their implications, if any, for alleviating health disparities? To investigate these questions, we conducted a comprehensive review of published studies on the impact of Web 2.0 on health. Although we are mindful of the increasing diversity of platforms in which scientific information is shared beyond traditional peer-reviewed venues (e.g., personal blogs, articles available through general Web-based searches), to delineate the scope of the study and make it more replicable, we focused on published references searchable through major bibliographic databases. We sought to (1) summarize existing descriptive studies of health-related Web 2.0 activities and efforts; (2) critically review a range of intervention studies, including feasibility, usability, pilot, and randomized clinical trial projects; and (3) discuss the implications of the current results for health promotion and health communication, particularly with marginalized communities. Note that this review adheres strictly to the defining characteristic of Web 2.0, namely its participatory nature; hence, it will not cover Web-based interventions without a user-generated component, or unidirectional mobile health programs. Finally, although numerous Web 2.0 programs provide information and social support to diverse populations, only a small portion have been empirically evaluated and reported in peer-reviewed journals; this review excludes unpublished and untested programs.
