Reach and effectiveness of a worksite health promotion program combining a preventive medical examination with motivational interviewing; a quasi-experimental study among workers in low socioeconomic position

BACKGROUND: This study aimed to evaluate individual characteristics associated with participation and effectiveness of a worksite health promotion program with motivational interviewing targeting health and health behaviour among Dutch workers in low socioeconomic position. METHODS: In a production company and a hospital, 838 workers were invited for a Preventive Medical Examination and subsequent coaching with motivational interviewing up to 7 sessions within 6 months. Follow-up information was collected after 6 months. Characteristics associated with participation in coaching were assessed with logistic regression models. The effectiveness of coaching on body mass index (BMI), bodyweight, self-rated health, vigorous physical activity, smoking, alcohol intake, fruit- and vegetable consumption, work ability, and sickness absence was evaluated with linear regression models and on participation in health promotion activities with logistic regression analysis. The analyses on effectiveness were performed without and with propensity score adjustment. RESULTS: Of the 838 invited workers, 313 workers participated in the Preventive Medical Examination and follow-up data were available for 176 workers, of whom 100 workers with increased cardiovascular risk attended coaching. The majority of workers with obesity (73%), overweight (60%), and unhealthy behaviours (58%-69%) at baseline participated in motivational interviewing. Males, workers with overweight or obesity, workers at the production company, workers with insufficient vigorous physical activity, and workers with a low educational level were most likely to participate in coaching. Coaching with motivational interviewing after the Preventive Medical Examination was associated with a 4.74 times higher likelihood [95% confidence interval (CI): 1.99;11.32] to participate in health promotion activities and 10.9% (95%CI: 0.6;21.3) more persons who quit smoking compared to workers without coaching. No statistically significant effects were observed on BMI, bodyweight, health, health behaviour, work ability and sickness absence. CONCLUSIONS: The program combining a Preventive Medical Examination with follow-up coaching reached – as intended – workers with obesity or overweight, those with a low education and with unhealthy behaviours. Adding coaching with motivational interviewing to a Preventive Medical Examination contributed to higher participation in health promotion activities and an increase in smoking cessation after 6 months among workers with a lower socioeconomic position, but was not effective on other outcomes. TRIAL REGISTRATION: The study was registered retrospectively in the Netherlands Trial Register as NL8178 on 22/11/2019. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-023-16908-w.