International patterns in the occurrence of Hodgkin's disease in children and young adult males.

It was reported over 20 years ago that there were distinct age-specific patterns of Hodgkin's disease incidence in countries with different levels of economic development, and that there was an inverse relationship between the incidence of Hodgkin's disease in children and young adults within countries. Such observations were important, leading to hypotheses on the possibly infectious aetiology of the disease. Since the initial report, diverging trends in the incidence of Hodgkin's disease in children and young adults have been observed, and data from a much larger number of countries and cancer registries have become available. This led us to reassess international age-related incidence patterns of Hodgkin's disease occurrence. Recent data show distinct differences in age-specific Hodgkin's disease incidence patterns in different geographic regions. In general, the United States (US) and European countries had the pattern of low childhood rates and high young adulthood rates. However, countries which are not part of the European Union (EU), mainly Baltic states and countries of central and eastern Europe, showed a variant of this pattern: similarly high young adult rates, but rates in children higher than those in the US and EU. Incidence-rate patterns for Latin American countries differed from those previously observed, with a shift towards patterns observed in more economically developed countries. Analysis of incidence data from earlier sources dating back to 1963 confirmed the original finding of an inverse association in incidence rates (c. 1963-1967) using a selected group of cancer registries, but not when all data were considered. This association has become weaker over the past 20 years. Using current incidence rates (1983-1987), no association between Hodgkin's disease rates in children aged 5 to 14 years (as well as 0 to 9 years) and young adults (20 to 34 years) was found.