Impact of a Worksite Diabetes Prevention Intervention on Diet Quality and Social Cognitive Influences of Health Behavior: A Randomized Controlled Trial.

OBJECTIVE To evaluate the impact of a worksite diabetes prevention intervention on secondary outcomes regarding the change in diet quality and components of the Health Action Process Approach (HAPA) theoretical framework. DESIGN Pretest-posttest control group design with 3-month follow-up. SETTING University worksite. PARTICIPANTS Employees aged 18-65 years with prediabetes (n = 68). INTERVENTION A 16-week group-based intervention adapted from the Diabetes Prevention Program. MAIN OUTCOME MEASURES Diet quality was assessed using the Alternative Healthy Eating Index 2010; HAPA components were assessed via written questionnaire. ANALYSIS Repeated-measures ANOVA compared the between- and within-group change in outcomes across time. RESULTS Significant difference occurred between groups for the change in consumption of nuts/legumes and red/processed meats postintervention and for fruits at 3-month follow-up (all P < .05); a significant increase in total Alternative Healthy Eating Index 2010 score occurred postintervention in the experimental group (P = .002). The changes in action planning, action self-efficacy, and coping self-efficacy from HAPA were significantly different between groups after the intervention; the change in outcome expectancies was significantly different between groups at 3-month follow-up (all P < .05). CONCLUSIONS AND IMPLICATIONS The worksite intervention facilitated improvement in diet quality and in planning and efficacious beliefs regarding diabetes prevention. Further research is needed to evaluate the long-term impact of the intervention.