Diffusion and dissemination of evidence-based dietary strategies for the prevention of cancer

We used a systematic review to identify strategies that have been evaluated for disseminating cancer control interventions that promote the uptake of a healthy diet in adults. Studies were identified by contacting technical experts and by searching medline, PreMedline, cancerlit, embase/Excerpta Medica, Psycinfo, cinahl, the Cochrane Database of Systematic Reviews, and reference lists. English-language primary studies were selected if they evaluated the dissemination of healthy diet interventions to individuals, health care providers, or institutions. Studies involving only children or adolescents were excluded. We retrieved 101 articles for full-text screening, and identified nine reports of seven distinct studies. Four of the studies were randomized trials, one was a cohort design, and three were descriptive studies. Six of the studies were rated methodologically weak, and one was rated moderate. Because of heterogeneity, low methodological quality, and incomplete data reporting, the studies were not pooled for meta-analysis. No beneficial dissemination strategies were found. One strategy involving the use of peer educators at the work site, which led to a short-term increase in fruit and vegetable intake, looks promising. Overall, the quality of the evidence is not strong, and the evidence that exists is more descriptive than evaluative. No clear conclusions can be drawn from these data. Controlled studies are needed to evaluate dissemination strategies and to compare dissemination and diffusion strategies that communicate different messages and target different audiences.