Characterising workplace dietary interventions reporting organisational-related outcomes: A systematic review

The workplace is considered an important setting for public health dietary interventions (1) . For employers, workplace wellbeing provision has the potential for cost-savings related to outcomes such as employee absenteeism, productivity, retention, and company reputation. Yet the evidence to support workplace dietary interventions against these outcomes is limited (2) . The aim of this study was to characterise workplace dietary intervention studies that have evaluated organisational-related outcomes. A systematic review (PROSPERO CRD42023454673) was conducted. Six databases, (Medline, Embase, Cochrane Library, Web of Science, APA PsycINFO, Business Source Complete) were searched for articles from 1990 to September 2023. Studies were screened in duplicate and included if they were a randomised controlled trial (RCT) or quasi-experimental design, conducted in a workplace setting in a high-income country, the intervention included a dietary component, and they reported organisational-related outcomes. A narrative synthesis was conducted to characterise study components (population, study design, study duration, intervention characteristics) and outcome measures (outcome measurement tools, unit of measure). From the 29,418 articles retrieved, 168 met the inclusion criteria. Most articles reported using a quasi-experimental (68.4%) design. Provision of educational materials (62.5%) and group nutritional education (56.0%) were the most frequently reported intervention components and, 82% were combined with a physical activity component. Of the included studies 20.2% were short-term interventions (≤ 3 months) and 42.3% studies were long-term (>12 months). Most studies (26.8%) did not report the personnel delivering the intervention, 25.6% of studies reported a dietitian or nutritionist were involved in delivering the intervention. Most interventions (63.7%) had at least one element of the intervention delivered face to face. Most studies (76.2%) were conducted in the USA or Canada, with 3.6% conducted in UK workplaces. The five main occupational settings reported were health and social care (19.8%), education (14%), manufacturing (12.2%), finance and insurance (11.0%) and public administration (8.1%). The three most frequently reported organisational-related outcomes were absenteeism (45.2%), healthcare costs (35.7%), and program return on investment (ROI) or cost benefit analysis (20.8%). Varied approaches were used to measure organisational-related outcomes, e.g., absenteeism was measured using self-reported WHO-Health and Work Performance questionnaire (3) , the Productivity and Disease questionnaire (4) , or objective methods such as human resource records. Economic outcomes e.g., healthcare costs and ROI were measured using insurance claims data and/or cost modelling. The results indicate a substantial volume of studies published evaluating dietary workplace interventions against organisational outcomes, although there is variation in how individual outcomes are measured. The review has found an over representation of studies conducted in North American organisations and limited studies conducted in the UK. The next stage of this study is to evaluate the effectiveness and quality of the evidence for dietary interventions to impact the organisational outcomes identified.