Prevalence and Incidence
Reliable estimates for the number of people with type 1 diabetes (prevalence) are very hard to find. For this reason, only prevalences for a selected group of countries is shown in the table below. Except for Finland, which has an unexplained high prevalence, the number of people with type 1 diabetes generally is around 480 per 100,000 or 0.048% of the population. Based on a prevalence of 0.048%, the number of people with type 1 diabetes in EU is 2.1 million and Europe 3.6 million. JDRF estimates the global number of people with type 1 diabetes to be 18.2 million 
The number of new cases of type 1 diabetes (incidence) is increasing worldwide, but there is considerable variation by country with some regions of the world having much higher incidence than others. The reasons for this are unclear but the rapid increase over time makes it impossible to explain by genetic susceptibility alone. Other factors, perhaps lifestyle related changes, such as rapid weight gain and/or inappropriate feeding in infancy, must play a role as well. The decreasing incidence of infections in western countries (the ‘hygiene hypothesis’) has also been suggested as a risk factor for the condition.
Of particular concern is the sharp increase in incidence among children, due to an increasingly lower age of the disease start. Because of that, type 1 diabetes is today one of the most common chronic diseases in childhood, and more children than ever will have to live with type 1 diabetes for life. No explanation has been found for this shift, which seems to be especially pronounced in northern countries, see diagram below .