Editor,— A recent article1 in this journal has commented on the part played by working conditions, especially psychosocial risk factors, in causing sickness absence, and two editorials have encouraged the need for research calling for action to improve the work environment and to assess its impact upon sickness absence.2 3

While we entirely agree with these views, the paths through which working conditions will lead to sickness absence are not clear. Sickness absence episodes are often medically certified as attributable to “common diseases”; that is, not work related diseases. In Spain, for example, we found that approximately three of four sickness absence episodes were medically certified as attributable to common diseases.4 This issue is important because it might partly explain the associations found in a number of studies between working conditions and sickness absence.5 If so, the impact of workplace preventive measures on sickness absence could be lower than expected. Alternatively, it could be …