Effect of a participatory ergonomics intervention on psychosocial factors at work in a randomized controlled trial
- Eira Viikari-Juntura (eira.viikari-juntura{at}ttl.fi)
- Merja Holtari-Leino (merja.holtari-leino{at}tsp.stm.fi)
- Sari Stenholm (sari.stenholm{at}ktl.fi)
Abstract
Objectives: To study the effect of a participatory ergonomics intervention on psychosocial factors at work among kitchen workers.
Design: A cluster randomized controlled trial.
Setting: Four cities in Finland in 2002-2005.
Participants: 504 workers of 119 municipal kitchens.
Intervention: Kitchens were randomized to intervention (n = 59) and control (n = 60) groups. The intervention lasted 11 to 14 months. It was based on the workers' active participation in work analysis, planning, and implementing the ergonomic changes aimed to decrease physical and mental workload.
Main outcome measures: Mental stress, mental strenuousness of work, hurry, job satisfaction, job control, skill discretion, co-worker relationships, supervisor support. Data were collected by questionnaire at baseline, at the end of the intervention, and at a 12- month follow-up (PI12).
Results: At the end of the intervention, the odds ratio (OR) of job dissatisfaction for the intervention group as compared with the control group was 3.0 (95% CI 1.1-8.5), of mental stress 2.3 (1.2-4.7) and of poor co-worker relationships 2.3 (1.0-5.2). At the PI12, the respective OR of job dissatisfaction was 3.0 (1.2-7.8). Analysis of the independent and joint effects of the intervention and extraneous organizational reforms showed that adverse changes were accentuated among those with exposure to both.
Conclusions: No favourable effects on psychosocial factors at work were found. The adverse changes were due to a joint effect of the intervention and the extraneous organizational reforms. The findings do not support the usefulness of this kind of intervention in changing unsatisfactory psychosocial working conditions.
