RESUMEN
The mortality caused by blood neoplasms in Argentina shows great irregularity. This was found to be caused in certain ways by (a) differences in the sexes and ages of the populations studied; (b) differences in available health services; and (c) environmental factors. Thus high rates and clusters of lymphomas and multiple mylomas were observed in zones with arsenical water, for example.In rural districts, the rates are lower, especially among old-aged people.Lower rates of leukemias were also observed among Spaniards compared to Italians (p=0.001) residing in Argentina. Turkish, Syrian, and Lebanese showed higher rates than Argentinians, Spaniards, or Italians.The results of a case-control study are given in which the following were observed: (a) Among the ancestors of cases HSN there are fewer Spaniards (not significant) and Latin-Americans (p=0.03) and more people who were born in Central or Eastern Europe (p=0.01). (b) In case group, there was more frequent contact with animals, especially dogs; and a greater exposure to petroleum and its products, and to insecticides.