Age-related differences in the trends of fatal Hodgkin's disease as a consequence of immune experience.

It has been proposed by MacMahon, on the basis of the variations among populations in the age distribution of fatal Hodgkin's disease, that there are two etiological factors, one important in young adults and the other important in middle-aged and elderly people. Correa has extended this by suggesting that those who died of the disease as young adults in developed countries would have succumbed to the disease as children under less favorable circumstances. In England and Wales, the mortality rate from Hodgkin's disease doubled from 1911 to 1970. If there were two etiologies, it seems unlikely that they would remain in step with one another over such a long period, when it was clear that some factor of major etiological importance was changing. Examination of the trends with time of the age-specific rates confirmed the previously reported decline in children and rise in elderly people and revealed a rapid rise in the mortality of young adults of both sexes. These changes were not compatible with any reasonable variations in the diagnosis or classification of Hodgkin's disease. Our data are compatible with the hypotheses that the etiology of the disease in young adults in different from that in elderly people and that the rise in the mortality of young adults is due to a transfer of deaths from the disease in childhood.