Work site-based cancer prevention: Primary results from the working well trial

Objectives. This paper presents the behavioral results of the Working Well Trial, the largest US work site cancer prevention and control trial to date. Methods. The Working Well Trial used a randomized, matched-pair evaluation design, with the work site as the unit of assignment and analysis. The study was conducted in 111 work sites (n = 28 000 workers). The effects of the intervention were evaluated by comparing changes in intervention and control work sites, as measured in cross-sectional surveys at baseline and follow-up. The 2-year intervention targeted both individuals and the work- site environment. Results. There occurred a net reduction in the percentage of energy obtained from fat consumption of 0.37 percentage points (P = .033), a net increase in fiber densities of 0.13 g/1000 kcal (P = .056), and an average increase in fruit and vegetable intake of 0.18 servings per day (P = .0001). Changes in tobacco use were in the desired direction but were not significant. Conclusions. Significant but small differences were observed for nutrition. Positive trends, but no significant results, were observed in trial-wide smoking outcomes. The observed net differences were small owing to the substantial secular changes in target behaviors.