title: Online prevention aimed at lifestyle behaviors: a systematic review of reviews.
abstract: BACKGROUND
  Interventions aimed at behavior change are increasingly being delivered over the Internet. Although research on intervention effectiveness has been widely conducted, their true public health impact as indicated by reach, effectiveness, and use is unclear.
  
  
  OBJECTIVE
  The aim of this paper is to (1) review the current literature on online prevention aimed at lifestyle behaviors, and (2) identify research gaps regarding reach, effectiveness, and use.
  
  
  METHODS
  A systematic search in PubMed revealed relevant literature published between 2005 and 2012 on Internet-delivered behavior change interventions aimed at dietary behaviors, physical activity, alcohol use, smoking, and condom use. Our search yielded 41 eligible reviews, which were analyzed in terms of reach, effectiveness, and use according to the RE-AIM framework.
  
  
  RESULTS
  According to health priorities, interventions are largely targeted at weight-related behaviors, such as physical activity and dietary behavior. Evaluations are predominantly effect-focused and overall effects are small, variable, and not sustainable. Determinants of effectiveness are unclear; effectiveness cannot yet be unambiguously attributed to isolated elements. Actual reach of interventions is undiversified, mostly reaching participants who are female, highly educated, white, and living in high-income countries. One of the most substantial problems in online prevention is the low use of the interventions, a phenomenon seen across all behavior domains.
  
  
  CONCLUSIONS
  More research is needed on effective elements instead of effective interventions, with special attention to long-term effectiveness. The reach and use of interventions need more scientific input to increase the public health impact of Internet-delivered interventions.
authors.affiliation: Department of Health Promotion, CAPHRI School for Public Health and Primary Care, Maastricht University, Maastricht, Netherlands.
authors.forename: Leonie F M
authors.initials: LF
authors.lastname: Kohl
authors.forename: Rik
authors.initials: R
authors.lastname: Crutzen
authors.forename: Nanne K
authors.initials: NK
authors.lastname: de Vries
mesh_terms: D001521:Behavior Therapy; D006801:Humans; D020407:Internet; D008019:Life Style
keywords: Internet; RE-AIM; eHealth; health behavior; life style; prevention; telemedicine