Nutrition intervention for high-risk auto workers: results of the Next Step Trial

Abstract

Background: The Next Step Trial tested interventions encouraging prevention and early detection practices in automotive-industry employees at increased colorectal cancer risk. This article describes results of the nutrition intervention promoting low-fat, high-fiber eating patterns.

Methods: Twenty-eight worksites (5,042 employees at baseline) were randomized to a 2-year nutrition intervention including classes, mailed self-help materials, and personalized dietary feedback. Control worksites received no intervention. Nutrition outcomes were assessed by mailed food frequency questionnaires (FFQs) Primary nutrition outcomes included percentage energy from fat and fiber density (g/1,000 kcal) at 1 year postrandomization. Secondary outcomes included servings of fruits/vegetables and dietary measures at 2 years postrandomization. Analyses were adjusted for within worksite correlations and baseline covariates. Fifty-eight percent of employees returned FFQs.

Results: At 1 year, there were modest but statistically significant intervention effects for fat (-0.9 %en), fiber (+0.5 g/1,000 kcal), and fruits/vegetables (+0.2 servings/day) (all P < 0.007). At 2 years, due to significant positive changes in control worksites, intervention effects were smaller, significant for fiber only. Intervention effects were larger in younger (<50 years), active employees and class attendees.

Conclusion: The nutrition intervention produced significant but modest effects on dietary fat and fiber and fruits/vegetables in these high-risk employees. Age and dose effects suggest younger employees may be more responsive to this intervention.