Background: To understand the potential influencing factors on the effectiveness of workplace health promotion interventions and examine whether workplace health culture and physical environment can mediate the relationship between workplace health promotion and intervention effectiveness.
Methods: A total of 719 participants from 10 Chinese government agencies were recruited for a prospective self-controlled trial. Questionnaires, qualitative interviews, and direct observation were used for the baseline evaluation, process evaluation, and effectiveness evaluation. Based on the results of the need assessment and risk assessment at each workplace, a two-year comprehensive health intervention was conducted by each workplace. Health outcomes including self-rated health (SRH) and mental health were measured at baseline and 24 months. Health culture was measured at 24 months. Physical environment and intervention implementation were measured at 12 months and 24 months.
Results: Compared with the baseline, the means of SRH and mental health increased significantly by 0.302 and 2.698, respectively. The SRH scores were different before and after intervention; furthermore, the differences varied by workplace. Health culture mediated the relationship between intervention implementation and intervention effectiveness, including SRH and mental health improvement, but physical environment did not. Physical environment quality was significantly negatively correlated with SRH improvement and mental health improvement. Under the relatively high-quality interventions with scores higher than 4.047 or 4.151 (out of 5), better health culture may led to greater SRH and mental health improvements.
Conclusions: Health culture may mediate the relationship between intervention implementation and intervention effectiveness, whereas physical environment does not seem to mediate this relationship. Under relatively high-quality interventions, a better health culture may lead to more positive improvements in SRH and mental health. Future studies will need to examine the physical environment as a moderating effect rather than mediating effect.
Trial registration: This study was retrospectively registered in Chinese Clinical Trial Registry.
Trial registration number: ChiCTR-OOC-16010059 . Date of registration: Dec 1, 2016.
Keywords: Health culture; Intervention implementation; Mediating effect; Physical environment; Workplace health promotion.