Review and Special Articles Telephone Interventions for Physical Activity and Dietary Behavior Change A Systematic Review Elizabeth G. Eakin, PhD, Sheleigh P. Lawler, PhD, Corneel Vandelanotte, PhD, Neville Owen, PhD Background: Given the epidemic of lifestyle-related chronic diseases, building the evidence base for physical activity and dietary behavior change interventions with a wide population reach is of critical importance. For this purpose, telephone counseling interventions have consid- erable potential. Purpose: To systematically review the literature on interventions for physical activity and dietary behavior change in which a telephone was the primary method of intervention delivery, with a focus on both internal and external validity. Methods: A structured search of PubMed, Medline, and PsycInfo was conducted for studies published in English from 1965 to January 2006. Studies targeted primary or secondary prevention in adults, used randomized designs, and included physical activity and/or dietary behavior outcomes. Results: Twenty-six studies were reviewed, including 16 on physical activity, six on dietary behavior, and four on physical activity plus dietary behavior. Twenty of 26 studies reported significant behavioral improvements. Positive outcomes were reported for 69% of physical activity studies, 83% of dietary behavior studies, and 75% of studies addressing both outcomes. Factors associated with positive outcomes appear to be the length of intervention and the number of calls, with interventions lasting 6 to 12 months and those including 12 or more calls producing the most favorable outcomes. Data on the representativeness of partici- pants, implementation of calls, and costs were reported much less frequently. Conclusions: There is now a solid evidence base supporting the efficacy of physical activity and dietary behavior change interventions in which the telephone is the primary intervention method. Thus, research studies on broader dissemination are necessary, and should address questions relevant to the translation of this body of work into population health practice. (Am J Prev Med 2007;32(5):419 – 434) © 2007 American Journal of Preventive Medicine Introduction P hysical activity and dietary behavior changes are important to the primary prevention and man- agement of all prevalent chronic conditions. Together they account for 17% of overall disease burden in the United States. 1 The population preva- lence of insufficient physical activity and inadequate diet is high among adults in industrialized countries. 2–4 This, combined with epidemic rates of lifestyle-related diseases and high rates of overweight and obesity, underline the imperative to develop population-based approaches to address these key health behaviors. There is now a large evidence base supporting the efficacy of physical activity and dietary behavior inter- ventions for adults, across a range of settings and target populations, and utilizing a range of intervention mo- dalities. 5–8 Many of these delivery modalities, including mailed print materials, computer-tailored interventions, and Internet-delivered interventions, have the potential for wide population reach. Telephone-delivered inter- ventions for physical activity and dietary behavior change also have this potential. The telephone remains one of the most widely available communication tools, and is likely to remain so for the foreseeable future. Telephone-delivered health behavior interventions also have the potential for being adopted by the growing number of government and nongovernmental agencies and health maintenance organizations that operate telephone information, support, and triage centers. 9 It is thus important that we understand what can be achieved via this important health behavior interven- tion delivery mechanism. From the Cancer Prevention Research Centre, School of Population Health, The University of Queensland, Brisbane, Australia Address correspondence and reprint requests to: Elizabeth G. Eakin, PhD, Cancer Prevention Research Centre, School of Popula- tion Health, The University of Queensland Herston Road, Herston Q, Australia 4006; E-mail: e.eakin@sph.uq.edu.au. 419 Am J Prev Med 2007;32(5) 0749-3797/07/$–see front matter © 2007 American Journal of Preventive Medicine • Published by Elsevier Inc. doi:10.1016/j.amepre.2007.01.004