The epidemic of type 2 diabetes is a statistical artefact

Excerpt

In recent years it has been claimed, with increasing intensity, that the world is experiencing an ongoing epidemic of diabetes. Linked to the increasing prevalence of obesity, this repeated assertion has resulted in increased awareness of diabetes as a public health problem and has stimulated efforts to develop measures for the primary prevention of diabetes. However, it is important to emphasise that the apparent ‘epidemic’ reflects an increasing prevalence of diabetes, as documented in repeated surveys of the same source population and discussed by Colagiuri et al. in this issue of Diabetologia [1]. Before we can accept the notion of a diabetes epidemic there is good reason to take a closer look at the epidemiological mechanisms underlying the changing demography of the condition. The prevalence of a chronic disease, such as diabetes, at a given point in time is the net result of the accumulated number of new cases (incidence) minus the accumulated number of deaths in the patient population up to that point in time. When the incidence is equal to the mortality in a demographically stable population, this population is considered to be in epidemiological equilibrium. Any change in incidence and/or mortality will disturb this equilibrium, and the prevalence of diabetes will be affected by changes in both incidence and mortality. Støvring et al. have reported the epidemiological characteristics of drug-treated diabetes in a Danish community [2]. Further scrutiny of the data set offers us the opportunity to examine possible explanations for the increasing prevalence of diabetes, as currently experienced worldwide [3, 4]. …