A four-year follow-up study of physical working conditions and perceived mental and physical strain among food industry workers

• Deteriorating physical working conditions increases physical and mental strain among food industry workers.
• The change in physical strain was associated with the change in mental strain.
• Younger employees were mostly affected due to poorer ergonomic factors at work.

This study hypothesized that in a longitudinal setting deteriorating physical working conditions increases the perceived physical and mental strain among food processing employees. The study was conducted in 2003 and 2007. It examined 248 blue-collar workers, all of whom were in the same occupation throughout the entire follow-up period. The data were obtained through a structural questionnaire distributed to the employees at the workplace. Mental strain had increased (7%) significantly among younger employees during the follow-up. The changes in mental strain for the younger employees were positively associated with the changes in physical strain. The changes in physical strain were also significantly associated with the changes in physical working conditions among both younger and the older workers. The results of this study partly support the study hypothesis, namely that deteriorating physical working condition increases physical strain and also increases mental strain, especially among younger employees.