Absence of conflict of interest.
Citation
Highlights
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The study’s objective was to examine the impact of a workplace wellness program on employees’ tenure, absenteeism, cholesterol, hypertension, and obesity.
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This study was a randomized controlled trial that assigned worksites to the treatment or comparison group and compared employees’ outcomes by worksite. The primary data sources were employment records and clinical biometric data.
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The study findings suggested that there was no statistically significant association between being offered the opportunity to participate in a workplace wellness program and employees’ tenure, absenteeism, or clinical measures of health.
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The quality of causal evidence presented in this report is low because the randomized controlled trial included individuals who joined after the study began and the authors did not ensure that the groups being compared were similar before the intervention. This means we cannot be confident that any estimated effects would be attributable to the workplace wellness program and not to other factors.
Intervention Examined
Workplace wellness program designed and implemented by Wellness Workdays
Features of the Intervention
Workplace wellness programs are widely implemented by employers with the goal of lowering health care costs and improving employee productivity. The workplace wellness program examined in this study was designed and implemented by Wellness Workdays, an established wellness vendor. The program was implemented over 18 months and consisted of eight modules, each lasting four to eight weeks. Modules focused on different topics like physical activity, stress reduction, nutrition, and prevention and were delivered by registered dietitians using both individual and team-based activities and challenges. Participants were provided small incentives for completing modules, averaging about $250 total across the program. The program was for workers at a large warehouse retail company, BJ’s Wholesale Club. All individuals in treatment worksites were eligible but not required to participate in the intervention.
Features of the Study
This study was a randomized controlled trial that randomly assigned 20 out of 160 eligible worksites to the treatment group and the remaining worksites to the comparison group. Individuals were assigned to treatment or comparison status based on their worksite, either at the time of randomization or when they first became employed by the company. Of comparison worksites, 20 were randomly selected as “primary control sites” for which survey and clinical data were collected. The remaining sites were “secondary control sites” for which only administrative data were collected.
The 20 worksites in the treatment group had 4,037 unique employees over the study period, of whom 2,266 were employed at the beginning of the study. The 20 “primary control sites” had 4,106 unique employees over the study period, of whom 2,336 were employed at the beginning of the study. The 120 “secondary control sites” had 24,831 unique individuals, of whom 13,766 were employed at the beginning of the study. The analytic sample size varies for the employment versus clinical health outcomes. Overall, about 54 percent of the sample was male, 56 percent identified as non-Hispanic White, and the mean age of employees the year prior to the intervention was about 39.
The workplace wellness program was voluntary, and the treatment group was offered the intervention as it was designed. Individuals in the comparison worksites did not have access to the wellness program. The primary data sources were employment records and clinical biometric measures collected by registered nurses. Employment records were collected throughout the study period for all individuals employed at the worksites, regardless of whether they were employed at the beginning of the study, end, or both. Clinical data were collected at the 20 treatment worksites and 20 primary control sites for individuals employed at the end of the study who volunteered to complete the screenings.
The authors used a statistical model to compare the outcomes of employees at treatment versus control worksites. The model controlled for age, sex, race, and initial employment characteristics like full-time versus part-time status and job category. The model also weighted individuals by exposure to the program as determined by the share of the study period an individual was employed at the worksite and number of hours they worked.
Findings
Employment
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The study findings suggested that there was no statistically significant association between being offered the opportunity to participate in a workplace wellness program and employee tenure.
Health and safety
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The study findings suggested that there was no statistically significant association between being offered the opportunity to participate in a workplace wellness program and absenteeism or clinical measures of health, including whether employees had high total cholesterol, low HDL cholesterol, hypertension, or were classified as obese.
Considerations for Interpreting the Findings
The authors reported that all worksites that were randomized remained in the study. However, the employee composition at each worksite changed over time. Employment outcomes were collected and analyzed for all individuals who were employed at the company at any time during the study, regardless of whether they were employed when the study began. In contrast, clinical outcomes were collected and analyzed only for individuals who were employed at the end of the study, regardless of whether they were employed at the company when the study began. Exact rates of study participant attrition – in this case, the proportion of study participants who dropped out of the study or declined to provide clinical data – could not be assessed due to the inclusion of new study participants who joined after the study began. Furthermore, the authors did not collect pre-intervention measures for any of the eligible outcomes. This means that preexisting differences between the treatment and control groups, rather than the intervention itself, could explain any observed differences in outcomes.
Causal Evidence Rating
The quality of causal evidence presented in this report is low because the randomized controlled trial included individuals who joined after the study began, and the authors did not ensure that the groups being compared were similar before the intervention. This means we cannot be confident that any estimated effects would be attributable to the workplace wellness program and not to other factors. However, the study did not find statistically significant effects.