It's official: hard work, stress makes you sick
The harder you work and the more stressed you are, the sicker you get, a large-scale Dutch study has confirmed. And if you're threatened with downsizing, you get sick even more often.
The research, part of the long-term Maastricht Cohort Study, involved 12,140 people - more than half of whom were followed over three years. Results were recently released by the Netherlands Organisation for Scientific Research, which financed the work.
"A large percentage of absenteeism is caused by infections," wrote Dr Danielle Mohren of Maastricht University, who led this particular part of the study. She classified representative infections to be the common cold, flu-like illnesses and gastroenteritis.
People who are working under the threat of restructure, those who are fatigued and people who have hit burn-out are at a much higher risk of having a common infection than other people, the study showed.
The biggest impact was noted in people who experience job insecurity: they suffered much from more cases of flu and gastroenteritis.
"Job insecurity due to downsizing and the closure of facilities has been connected to negative charges in self-rated health, increases in longstanding illness, adverse sleep patterns, minor psychiatric morbidity, increase in sickness absence and somatic symptoms," wrote Mohren.
She also found that stress at work also created fatigue, which enhanced the chances of infection. "Fatigue is a frequent symptom during infections," she said, and employees working shifts have a higher chance of developing infections than daytime employees, with the risk greatest for those working three shifts.
Burnout - defined by exhaustion, cynicism and professional efficacy - doubles an individual's chance of suffering from gastroenteritis.
Employees in highly demanding jobs suffer from colds 20 per cent more often than employees in less demanding positions. But employees who took time off because they had a cold, often did this because they were not motivated. They exhibited little commitment in the work or little job satisfaction.
The research looked at work-related factors and the occurrence of acute common infections, and the potential role of fatigue in this relationship.
The study relied on an initial questionnaire sent to 27,000 people in 1998, of which 12,140 responded. Participants then received another eight questionnaires at four-monthly intervals. Although some dropped out, more than 8,000 employees from various companies were followed over a three year period.
The participants were asked to self-evaluate their symptoms of common infections. To ensure the accuracy of the replies, Mohren compared the reports of acute common infections with weekly virology reports. The researchers also examined the working environment of respondents.
The study allowed for differences due to age, sex, asthma, smoking, alcohol use, having young children and holding a leadership position. Researchers assumed that if participants had a demanding job, they would probably have more common colds than people who take it easy at work.
While work is only one of the reasons behind common infections, wrote Mohren, "it should be considered an important risk factor."
The study was part of the "Fatigue at Work" research program financed by the Netherlands Organisation for Scientific Research, and some of the results have been published in the Journal of Psychosomatic Research.