Abstract and Introduction
The incidence of childhood type 1 diabetes increased worldwide in the closing decades of the 20th century, but the origins of this increase are poorly documented. A search through the early literature revealed a number of useful but neglected sources, particularly in Scandinavia. While these do not meet the exacting standards of more recent surveys, tentative conclusions can be drawn concerning long-term changes in the demography of the disease. Childhood type 1 diabetes was rare but well recognized before the introduction of insulin. Low incidence and prevalence rates were recorded in several countries over the period 1920-1950, and one carefully performed study showed no change in childhood incidence over the period 1925-1955. An almost simultaneous upturn was documented in several countries around the mid-century. The overall pattern since then is one of linear increase, with evidence of a plateau in some high-incidence populations and of a catch-up phenomenon in some low-incidence areas. Steep rises in the age-group under 5 years have been recorded recently. The disease process underlying type 1 diabetes has changed over time and continues to evolve. Understanding why and how this produced the pandemic of childhood diabetes would be an important step toward reversing it.
At the start of the 20th century, childhood diabetes was rare and rapidly fatal. By its end, some 3-4 children per 1,000 in Western countries would require insulin treatment by the age of 20 years, and a steady rise in incidence had been reported from many other parts of the world. This increase has been extensively documented over the past two decades, over which time standard means of data collection have been agreed, central registries have been established, and numerous epidemiological studies have been reported[1,2]. In contrast, relatively little is known about the frequency of the disease in the early part of the century. It is easy to forget that by 1980 only a handful of studies were available, the "hot spots" in Finland and Sardinia were unrecognized, and no adequate estimates were available for 90% of the world's population.
The changing demography of childhood diabetes has major implications for our understanding of the disease. A rapid change in incidence within a genetically stable population implies that nongenetic factors are active and that the influence of genes is relative to population, time, and place. It suggests that something has changed in the environment our children encounter or in the way they are reared. Understanding this historical change would open the way to rational forms of intervention, which could be introduced at the stage of development when they are most likely to prove effective. Seen from this perspective, the central task of diabetes prevention is to understand a historical trend, and to put it in reverse.
It is therefore important to reach a clear overview of the way the disease has changed over time. Did childhood diabetes really become more common in the 20th century? If so, when and where did the increase begin? Is there an overall pattern to the increase? What inferences can we draw concerning its environmental causes? These considerations prompted a reexamination of the older literature. For all its limitations, this contains all that we will ever know concerning the origins of childhood diabetes, and it seemed helpful to try and put this together. I will argue that a number of valuable and neglected sources exist, and that useful inferences can be drawn about the rise of childhood diabetes over the course of the 20th century.
Diabetes. 2002;51(12) © 2002 American Diabetes Association, Inc.
Cite this: The Rise of Childhood Type 1 Diabetes in the 20th Century - Medscape - Dec 01, 2002.