Chromosome aberrations in divers

The incidence of chromosome gain and loss and chromosomal aberrations has been measured in 48-h lymphocyte cultures of divers and control subjects as part of an overall research program to identify possible long-term health hazards associated with commercial diving. When the two diving groups, air divers (n = 77) and helium-oxygen divers (n = 76), are compared with two control groups, oil rig workers (n = 75) and nonoil industry controls (n = 52), 3.9% (6 out of 153) had an unusually high number of structural aberrations in a small portion of the dividing lymphocytes. Similar damage was not found in controls. The remaining 147 divers had a similar low incidence of chromosomal aberrations to the two control groups. The factors responsible for this phenomenon are not known, but several aspects of diving can effectively be ruled out. These are: direct effects of pressure, breathing mixture, radiographic exposure, and viral infection. The causative agent must be acting locally on lymphocytes after their last maturation division. Further studies are continuing on this topic in an effort to identify the causative factor or factors.