The Australian National Workplace Health Project: design and baseline findings.
BACKGROUND: This paper describes the study design, recruitment, measurement, and initial recruitment outcomes of Australia's largest workplace intervention trial, the National Workplace Health Project. METHODS: This was a cluster-randomized trial of socio-behavioral and environmental interventions focusing on key behaviors of physical activity, healthy food choices, cigarette smoking, and alcohol consumption, as well as motivational readiness for change. Twenty worksites were randomized separately for each intervention using a two-by-two factorial design. All participants underwent a health risk appraisal and measurements were made at baseline and at 1 and 2 years. RESULTS: The overall response rate for the baseline survey was 73% with 61% attending the health risk appraisal. The sample was predominantly male, English-speaking, married, blue-collar workers. Overall, 12% reported unsafe alcohol consumption, 26% were current smokers, 44% were physically inactive, 74% ate at most one piece of fruit per day, and 26% ate at most one serving of vegetables per day. Intervention and control conditions were similar at baseline for the primary outcomes, except that a higher proportion of the sociobehavioral intervention condition was more physically active (59%) than the corresponding control condition (53%). CONCLUSIONS: This study will permit the rigorous evaluation of the efficacy of sociobehavioral and environ mental intervention approaches to workplace health promotion. Although participants were randomized by worksite, intervention and control conditions were similar at baseline; any differences in the primary out come variables will be controlled for in the analysis.