Durability and diffusion of the nutrition intervention in the working well trial

Background. The Working Well Trial (WWT) emphasized employee participation in the planning and implementation of the health promotion intervention. These participatory strategies were intended to promote institutionalization of the health promotion program and thereby encourage maintenance of the intervention activities. We used data from 107 worksites in the WWT to test whether the nutrition intervention activities were maintained after the research program (i.e., durability) or were adopted by control sites (i.e., diffusion). Methods. At baseline, upon the completion of the 2-year intervention, and 2 years later, we conducted organization surveys regarding worksite health promotion activities. A nutrition activity score from 0 to 3 was calculated based on availability of nutrition-related programs, self-help manuals or guides, and videos, tapes, brochures, or posters. Results. From baseline to the end of the intervention, there was a significant increase in the nutrition activity score in intervention worksites compared with the controls (P < 0.001). However, 2 years later, there was no difference between intervention and control worksites. In addition, there was no significant increase in the nutrition activity score in control site 2 years after they received the intervention protocols and materials. Conclusions. Research is needed to develop and test worksite- based interventions to promote institutionalization, durability, and diffusion.