Objective: To evaluate long-term change in fruit and vegetable intake following a group randomized trial of worksites.
Methods: Medium-sized blue-collar businesses in the Seattle metropolitan area were recruited. Intake was assessed using serial cross-sectional samples of current workforce at 3 time points. The multilevel 18-month intervention involved partnership with the companies. Long-term follow-up was at 4.4 years postbaseline. Statistical analysis used general linear models, adjusting for worksite random effects.
Results: Initially, 45 worksites were randomized, with 29 agreeing to participate in a new study. Fruits and vegetable intake increased, with larger sustained changes in the intervention worksites, resulting in a long-term differential change of 0.25 servings per day, 95% confidence interval (0.09 to 0.40).
Conclusions: Intervention sustained small effects at 4 years, including 2 years with no contact. Although effects were not large, this low-intensity intervention approach could provide an important public health model.