The study revealed that employees in highly demanding jobs suffered from colds 20 percent more often than employees in less demanding positions. Also job insecurity, for example as a result of reorganisations, leads to an increase in flu and gastroenteritis in particular. Employees working shifts have a higher chance of developing infections than daytime employees. The risk is greatest among those who work in a three-shift system.
The research also demonstrated that fatigue, and in particular burnout, increased the risk of infections. For example, employees with burnout complaints suffered from gastroenteritis almost twice as often as employees without burnout.
Mohren also investigated which factors in the workplace played a role in absenteeism due to infection. Employees who were absent due to having a cold, often did this because they were not motivated. They exhibited little commitment in the work or little job satisfaction.
In 1998 the Maastricht research group started its investigation with a questionnaire sent to more than 27,000 employees. More than 12,000 people responded. Subsequently these persons received an extensive questionnaire once per year and a short questionnaire twice per year. Amongst other things these enquired about the occurrence of acute infections. The researchers also examined the working environment of the respondents.
The use of questionnaires in a large-scale study is almost unavoidable, but has the disadvantage that the research results can be an underestimation or overestimation of the effects found. Yet despite this, the study shows a clear link between working conditions and health.
Mohren's research is part of the Netherlands Organisation for Scientific Research Priority Programme 'Fatigue at work'.
For further information please contact Dr Danielle Mohren (Department of Epidemiology, Maastricht University), tel. 31-433-882-363, fax 31-433-884-128, e-mail: firstname.lastname@example.org. The doctoral thesis was defended on 31 January 2003. Ms Mohren's supervisors were Prof. C.P. van Schayck (Maastricht University) and Prof. J.M.D. Galama (University of Nijmegen).
The research was funded by the Netherlands Organisation for Scientific Research (NWO).