Mental-health problems and 'medically-unexplained,' musculoskeletal problems (which can themselves be a symptom of mental distress) are the main reasons people are off sick from work. People's perception of their work environment has been linked to a tendency to take time off sick but objective measurement of the workplace does not show this link. In other words it is what people think about their work, rather than the work itself that makes them more or less likely to take time off work. A study of 7,183 people in Aberdeen looked at the links between people's temperament as children and how likely they were to be signed off work sick as adults. They found that the children whose teachers said they 'often complains of aches and pains,' or 'often appears miserable or unhappy,' were much more likely to be permanently sick or disabled as adults.
Henderson, Max, Hotopf, Matthew and Leon, David A. - Childhood temperament and long-term sickness absence in adult life British Journal of Psychiatry March 2009, 194(3), 220-223