The effect of an app-based health intervention on somatic symptoms among employees of the DHL Group : a longitudinal pilot study

Abstract

Background Somatic symptoms significantly contribute to absenteeism and healthcare costs, particularly in physically demanding professions such as postal and delivery services. The FC-Fit Challenge, an app-based workplace health intervention, aims to promote healthier lifestyles through personalized feedback, social interaction, and professional guidance, targeting lifestyle changes and reducing somatic symptoms. Objectives This study evaluated the effect of the FC-Fit Winterchallenge 2021/22 on somatic symptoms over time, considering sociodemographic and work-related differences, and identified predictors of somatic symptoms to inform workplace health strategies. Methods A longitudinal design with three measurement points was employed: at the start of the intervention (T1), immediately post-intervention (T2), and three-month follow-up (T3). At T1, 497 participants completed the survey. Sociodemographic and work-related variables, health behaviors, and mental health indicators were analyzed. Multiple regression identified significant predictors of somatic symptoms. Results Somatic symptoms significantly decreased post-intervention (T1: 7.0 ± 4.6 vs. T2: 5.9 ± 4.5, p < 0.001), with sustained effects at T3. Women, full-time employees, and administrative staff showed the most pronounced reductions. Predictors of higher somatic symptom severity included female gender, lower education, painkiller use, stress, and burnout, while high physical activity was associated with lower severity. Subgroup analysis revealed variability in intervention effectiveness based on sociodemographic and occupational factors. Conclusions The FC-Fit Challenge is a promising, scalable tool for workplace health promotion. Tailoring interventions to specific employee profiles and addressing predictors like stress and burnout can optimize outcomes. Future studies should target underrepresented groups, such as delivery workers, and use randomized controlled designs to validate findings.