title: Preventive Health Behavior Change Text Message Interventions: A Meta-analysis.
abstract: BACKGROUND
  Existing evidence shows that text message interventions can produce short-term health behavior change. However, understanding is limited regarding intervention characteristics moderating this effect or the long-term effectiveness of text message interventions on behavior change after contact stops.
  
  
  METHODS
  MEDLINE, PubMed Central, ERIC, PsycINFO, and Web of Science were searched for articles published between April 2008 and December 2014 that evaluated an intervention targeting preventive health behaviors, delivered primarily by text message.
  
  
  RESULTS
  Intervention development and design characteristics and research outcomes were evaluated for 51 studies. Thirty-five studies were included in a meta-analysis (conducted in 2015) examining overall effect size and moderators of effect size. The overall pooled effect of interventions was d=0.24 (95% CI=0.16, 0.32, p<0.001) using outcome data collected most proximal to intervention cessation. Seven studies collected data following a no-intervention maintenance period and showed a small but significant pooled maintenance effect (d=0.17, 95% CI=0.03, 0.31, p=0.017, k=7). Few variables significantly moderated intervention efficacy. Interventions that did not use a theoretic basis, used supplementary intervention components, and had a duration of 6-12 months were most effective. The specific behavior being targeted was not associated with differences in efficacy nor was tailoring, targeting, or personalization of text message content.
  
  
  CONCLUSIONS
  Text message interventions are capable of producing positive change in preventive health behaviors. Preliminary evidence indicates that these effects can be maintained after the intervention stops. The moderator analysis findings are at odds with previous research, suggesting a need to examine moderators at the behavior-specific level.
authors.affiliation: Queensland University of Technology, Institute of Health and Biomedical Innovation, School of Public Health and Social Work, Brisbane, Australia. Electronic address: ashleigh.armanasco@gmail.com.
authors.forename: Ashleigh A
authors.initials: AA
authors.lastname: Armanasco
authors.affiliation: Queensland University of Technology, Institute of Health and Biomedical Innovation, School of Public Health and Social Work, Brisbane, Australia.
authors.forename: Yvette D
authors.initials: YD
authors.lastname: Miller
authors.affiliation: The University of Queensland, Cancer Prevention Research Centre, School of Public Health, BrisbaneAustralia.
authors.forename: Brianna S
authors.initials: BS
authors.lastname: Fjeldsoe
authors.affiliation: Queensland University of Technology, Institute of Health and Biomedical Innovation, School of Public Health and Social Work, Brisbane, Australia.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Marshall
mesh_terms: D015438:Health Behavior; D006801:Humans; D011314:Preventive Health Services / Q000379:methods*; D016540:Smoking Cessation / Q000379:methods; D060145:Text Messaging