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Effect of a participatory ergonomics intervention on psychosocial factors at work in a randomised controlled trial
  1. Eija Haukka1,
  2. Irmeli Pehkonen1,
  3. Päivi Leino-Arjas1,
  4. Eira Viikari-Juntura1,
  5. Esa-Pekka Takala1,
  6. Antti Malmivaara2,
  7. Leila Hopsu1,
  8. Pertti Mutanen1,
  9. Ritva Ketola1,
  10. Tuija Virtanen1,
  11. Merja Holtari-Leino3,
  12. Jaana Nykänen1,
  13. Sari Stenholm4,5,
  14. Anneli Ojajärvi1,
  15. Hilkka Riihimäki1
  1. 1Finnish Institute of Occupational Health, Helsinki, Finland
  2. 2National Institute for Health and Welfare, Helsinki, Finland
  3. 3Occupational Safety and Health Inspectorate of Turku and Pori, Turku, Finland
  4. 4National Institute for Health and Welfare, Helsinki, Finland
  5. 5National Institute on Aging, Baltimore, USA
  1. Correspondence to Eija Haukka, Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FI-00250, Helsinki, Finland; Eija.Haukka{at}


Objectives To study the effect of a participatory ergonomics intervention on psychosocial factors among kitchen workers.

Design A cluster randomised controlled trial.

Setting Four cities in Finland, 2002–2005.

Participants 504 workers in 119 municipal kitchens.

Intervention Kitchens were randomised to intervention (n=59) and control (n=60) groups. The intervention lasted 11–14 months and was based on the workers' active participation in work analysis, planning and implementing the ergonomic changes aimed at decreasing the physical and mental workload.

Main outcome measures Mental stress, mental strenuousness of work, hurry, job satisfaction, job control, skill discretion, co-worker relationships and 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 OR of job dissatisfaction for the intervention group as compared with the control group was 3.0 (95% CI 1.1 to 8.5), of mental stress 2.3 (1.2 to 4.7) and of poor co-worker relationships 2.3 (1.0 to 5.2). At the PI12, the OR of job dissatisfaction was 3.0 (1.2 to 7.8). Analysis of the independent and joint effects of the intervention and unconnected organisational 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 unconnected organisational reforms. The findings do not support the usefulness of this kind of intervention in changing unsatisfactory psychosocial working conditions.

  • Psychosocial factors
  • intervention
  • ergonomics
  • organisational reform
  • kitchen work
  • cluster randomised controlled trial

Statistics from


  • Funding The Academy of Finland (Health Promotion Research Programme), the Finnish Work Environment Fund, the Ministry of Labour and the Local Government Pensions Institution supported the study.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the Ethics Committee of the Finnish Institute of Occupational Health.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Policy-implications The findings of the present trial do not support the efficacy of this kind of participatory ergonomic intervention in changing unsatisfactory psychosocial working conditions. If organisational reforms occur simultaneously, it may be worthwhile to be cautious with the implementation of separate workplace interventions.

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