Importance of updating old cohorts for new findings

Mustard gas, or sulfur mustard, is a chemical with devastating acute toxic effects. The development, production, acquisition, stockpiling and transfer of all chemical weapons, including mustard gas, were banned by The Chemical Weapons Convention of 1997. However, mustard gas was used as a chemical warfare agent during many international political conflicts and wars of the twentieth century. A known, highly toxic, mutagenic carcinogen in animal models and an established carcinogen in humans,1 mustard gas has caused much human suffering, invalidating and even killing people. The acute toxic manifestations of exposure to mustard gas consist of epithelial detachment, necrosis in the respiratory system, skin and eyes and sometimes gastric complications. The long-term health consequences of such exposure include epithelial fibrosis and cancer and have been the subject of long-term follow-up studies, especially among military personnel and inhabitants of war-stricken areas in which chemical weapons were used.2 So, does the study by Mukaida et al 3 bring anything new to the existing knowledge on the consequences of long-term exposure to mustard gas? We are convinced that that answer is yes, and here we will dwell on the reasons why. First of all, the …