Dietary interventions to prevent and manage diabetes in worksite settings: a meta‐analysis

Objectives The translation of lifestyle intervention to improve glucose tolerance into the workplace has been rare. The objective of this meta‐analysis is to summarize the evidence for the effectiveness of dietary interventions in worksite settings on lowering blood sugar levels. Methods We searched for studies in Pub‐Med, Embase, Econlit, Ovid, Cochrane, Web of Science, and Cumulative Index to Nursing and Allied Health Literature. Search terms were as follows : (1) Exposurebased: nutrition/diet/dietary intervention/health promotion / primary prevention / health behavior / health education/food /program evaluation; (2) Outcome‐based: diabetes/hyperglycemia/glucose/HbA1c/glycated hemoglobin; and (3) Setting‐based: workplace/worksite/occupational/industry/job/employee. We manually searched review articles and reference lists of articles identified from 1969 to December 2016. We tested for between‐studies heterogeneity and calculated the pooled effect sizes for changes in HbA1c (%) and fasting glucose (mg/d l )using random effect models for meta‐analysis in 2016. Results A total of 17 articles out of 1663 initially selected articles were included in the meta‐analysis. With a random‐effects model, worksite dietary interventions led to a pooled −0.18% (95% CI, −0.29 to −0.06; P<0.001) difference in HbA1c. With the random‐effects model, the interventions resulted in 2.60 mg/d l lower fasting glucose with borderline significance (95% CI: −5.27 to 0.08, P= 0.06). In the multivariate meta‐regression model, the interventions with high percent of female participants and that used the intervention directly delivered to individuals, rather the environment changes, were associated with more effective interventions. Conclusion Workplace dietary interventions can improve HbA1c. The effects were larger for the interventions with greater number of female participants and with individual‐level interventions.