Written informed consent statement forms were obtained from participants. The right to withdraw and autonomy of responses were also explained. This study received approval from the ethics committee of the Fudan University School of Public Health, China. A prospective self-controlled trial was carried out between 2012 and 2014 in Shanghai. Primary outcomes, including SRH and mental health, were measured at baseline and after 24 months. Health culture was measured at 24 months. Physical environment and intervention implementation were measured at 12 months and 24 months. Questionnaires, qualitative interviews, and direct observation were used for the baseline evaluation, process evaluation, and effectiveness evaluation. The study began on June 15, 2012, and follow-up continued until September 30, 2014. Please refer to Additional file 1 for details of the study protocol.
Participants were recruited from 10 government agencies in Shanghai, China. The inclusion criteria for participants were (1) having signed an employment contract and (2) having signed a written informed consent form. A total of 1007 participants were recruited for the study, of whom 719 (71.4%) completed the questionnaire at the baseline and final follow-up.
The intervention was developed based on the WHO Healthy Workplace Model . We identified four areas—physical work environment, psychosocial work environment, personal health resources, and enterprise community involvement—in which actions towards a healthy workplace could be taken, and seven steps towards achieving effective health promotion. Step 1 is to mobilize employers and employees to invest in change. Step 2 is to help them assemble a “healthy workplace team” and resources to work on implementing a particular change in the workplace. Step 3 is to develop an assessment to collect the baseline data on employee demographics, health status, lifestyle, and psychosocial work environment (for example, job demand and job control). Step 4 is to determine the priorities that are most essential to health. Step 5 is to devise a health plan. Step 6 is to conduct the intervention. Step 7 is to evaluate the implementation process as well as the outcomes. Step 8 is to improve the program based on the evaluation results.
Considering the characteristics of civil servants, the development of the detailed program plan was based on four key steps:
At the start of the program, we recruited the top management of each government agency that committed to the program. The agencies agreed to invest essential human and financial resources into health promotion.
In the baseline survey, need assessment was conducted in each workplace to collect the baseline data and explore the employees’ needs, including the content, pattern, time, and frequency of intervention. Each workplace received a report on the baseline investigation, which included the employees’ demographic characteristics, health statuses, lifestyles, work-related characteristics, and health promotion demand. Some priority problems were determined based on prevalence, correlation with other risk factors, impact potential, and consistency between management’s ideas and the views of employees.
Based on investigation of the literature, a template for an intervention program was designed by the researchers. The program consisted of four main parts, which focused on tobacco control, physical activity, nutrition and diet, and work stress. Each workplace then designed an intervention plan based on the actual conditions and baseline data of that workplace. Each plan was improved by the researchers.
Each workplace assembled a “healthy workplace team”, which had several members and received financial support dedicated to health promotion. Focusing on the key problems, each workplace made targeted efforts to promote employees’ health. Some common interventions were as follows: For tobacco control, each workplace enacted measures such as banning smoking indoors, banning smoking in the office, having managers lead by example by not smoking themselves, and posting no-smoking signs. For physical activity, space was expanded, more exercise facilities were provided, interest groups were organized and given financial support, and employees were encouraged to walk rather than take the elevator by posters hung at decision points. For nutrition and diet, salt and oil dosage were recorded by the employer every working day; healthy eating habits were introduced by means such as lectures, leaflets, posters, and videos; and food intake recommendations were offered using color codes (red for limited intake; yellow for appropriate intake; green for recommended intake). For stress management, social activities were organized and lectures on mental health were held.
Self-reported demographic variables included gender, age, marital status, education, and length of employment. Age, education, and length of employment were each separated into four categories. The four age categories were < 30, 30–39, 40–49, and ≥ 50. The four education categories were junior high school, high school/technical secondary school, junior college, and bachelor/master’s/doctorate degree. The four length of employment categories were < 5 years, 5–14 years, 15–24 years, and ≥ 25 years.
Primary outcome measures
SRH was one of the main health outcomes we examined. In both the baseline and final survey, respondents were asked to rate their own general health on a five-point scale ranging from perfect to poor. SRH was generally assessed by a single survey question inviting participants to provide a subjective assessment of their health. Respondents answered “would you say that in general your health is perfect, very good, good, fair, or poor?” on a 5-piont scale ranging from perfect to poor . The difference between the baseline and final data was included in the analysis as a continuous dependent variable.
The other main health outcome, mental health, was measured by the Chinese version of the WHO-Five Well-Being Index. The WHO-5 has been found to be reliable and valid in previous studies [16, 17]. Respondents were asked to rate their status over the past 14 days. For example, how often have you felt quiet and relaxed ? Each item was rated on a six-point scale ranging from 0 (never) to 5 (all the time). The difference between the baseline and final scores was included in the analysis as a continuous dependent variable.
Potential influencing factors on intervention effectiveness
Implementation of intervention
We developed the Chinese Workplace Health Scorecard based on the CDC Workplace Health Scorecard , with adjustments based on the Chinese context. We organized 10 personal qualitative interviews to collect data about the implementation of intervention from the health promotion staff of each workplace. During the interviews, The Scorecard was filled out by the health promotion staff of each workplace to evaluate overall health promotion and specialized health promotion. Overall health promotion was assessed by 12 questions that focused on need assessment and health promotion programs. Each item was rated on a scale from 1 to 5, with a higher score indicating better overall health promotion. Specialized health promotion was divided into five parts: tobacco control, diet, physical activity, weight control, and stress management. Each part included several items rated on a scale from 1 to 5, with a higher score indicating better specialized health promotion. The average of the overall and specialized health promotion scores was calculated to obtain the intervention implementation score and included in the analysis as a continuous variable.
Workplace health culture
Based on the Chinese context, we developed the Workplace Health Culture Scale. The scale included 20 items divided into five dimensions: individual health culture, adverse health behaviors of direct leadership, adverse health effects of direct leadership, beneficial health effects of direct leadership, and overall health culture . More detailed information about the items can be found in another article . Each item was rated on a scale from 1 to 5, with a higher score indicating better workplace health culture. Each of the five domains was measured by the average of the ratings of the items. The scores on the five dimensions were averaged to obtain the overall score, which was included in the analysis as a continuous variable. The effects of workplace health culture were derived from the intervention effectiveness evaluation.
Workplace physical environment
The workplace physical environment varied among workplaces, but did not vary among individuals in the same workplace. Therefore, the workplace physical environment was assessed by direct observation. There were four trained observers who were responsible for visiting each workplace and using the Direct Observation Scoring Table to record their observations. During the field visit, the health promotion staff of each workplace guided the observers and answered the necessary questions. The assessment content of the Direct Observation Scoring Table was divided into four parts: overall environment, physical activity environment, tobacco control environment, and nutritional/dietary environment. Each part consisted of 3 items rated on a scale from 1 to 5, for a maximum total of 60 points. The mean of the total scores among the observers was computed as the physical environment score of each workplace. The average value of the process evaluation and effectiveness evaluation was included in the analysis as a continuous variable. Please refer to Additional file 2 for details of Direct Observation Scoring Table.
The questionnaires were self-filled by the respondents. Trained investigators were responsible for on-site quality control, including answering questions and asking respondents to complete any missing items on the questionnaires.
Using the Direct Observation Scoring Table, each trained observer rated the health environment of the workplace independently through field observation.
Descriptive analyses, t tests, and multiple regressions were conducted for the quantitative data using Epidata 3.1, Excel 2010, and Statistical Package for Social Sciences 20.0. To evaluate the effectiveness of an intervention, first, a paired t test was used; then, repeated measurement and analysis of variance were performed. Multiple regression analysis was conducted to determine whether health culture and physical environment could mediate the relationship between intervention implementation and intervention effectiveness.